Nobody takes just one supplement.

Also printed as: acesulfame potassium, acesulfame k, ace-k, E950, INS 950

Often blended with other sweeteners to round out the taste.

What the research says Not an active ingredient

Approved within set limits.

• Sweetener Approved within set limits. Present for taste, not for any benefit.

Worth knowing: Considered safe within approved limits.

Source: EFSA sweetener assessments

Aloe barbadensis

Also printed as: aloe barbadensis, aloe vera gel, aloe latex, lidah buaya, aloe

The inner gel and the outer latex are very different. Gel is used on skin and in drinks; latex is a strong laxative.

What the research says Limited human evidence

Some support for topical use on minor burns. Oral use has little good evidence and real safety concerns.

• Reports of liver injury Uncommon but documented cases of liver damage. Stop and seek advice if you notice yellowing of the eyes, dark urine, pale stools or unusual tiredness.
• Not suitable in pregnancy Avoid while pregnant or breastfeeding, or while trying to conceive, unless a doctor has said otherwise.
• Commonly upsets digestion Bloating, wind or loose stools are the usual complaints, especially at first.

Worth knowing: Oral aloe latex is not considered safe for regular use and has been linked to liver injury. Avoid in pregnancy.

Source: NIH NCCIH, Aloe Vera

Also printed as: alpha lipoic acid, ALA, thioctic acid, R-lipoic acid, alpha-lipoic

Sold for nerve symptoms and blood sugar.

What the research says Limited human evidence

Some trial support for diabetic neuropathy symptoms, mostly from intravenous studies. Oral evidence is weaker.

• Affects blood sugar Can lower blood sugar. If you take diabetes medication, this can stack with it.

Worth knowing: Can lower blood sugar, which matters if you take diabetes medication.

Source: NCBI literature overview

Phyllanthus emblica

Also printed as: phyllanthus emblica, emblica officinalis, indian gooseberry, amalaki, amla

A fruit high in vitamin C and polyphenols, used in Ayurvedic preparations.

What the research says Limited human evidence

Small trials, mostly from India, report effects on lipid markers. Evidence is limited and largely from one region.

• May increase bleeding Worth knowing before surgery or dental work, and if you take aspirin or a blood thinner.
• Affects blood sugar Can lower blood sugar. If you take diabetes medication, this can stack with it.

Worth knowing: May increase bleeding risk. Check first if you take blood thinners or diabetes medication.

Source: NCBI literature overview

Withania somnifera

Also printed as: withania somnifera, indian ginseng, winter cherry, KSM-66, Sensoril, withanolides, ashwaganda, asgandh

Traditional Ayurvedic plant. Trials almost always use a specific standardised root extract, and different preparations are not interchangeable.

What the research says Some human evidence

Several small trials report improvements in self-reported stress and sleep quality. Trials were short, mostly industry-funded, and used particular branded extracts.

• Not suitable in pregnancy Avoid while pregnant or breastfeeding, or while trying to conceive, unless a doctor has said otherwise.
• Affects the thyroid Relevant if you have a thyroid condition or take thyroid medication.
• Reports of liver injury Uncommon but documented cases of liver damage. Stop and seek advice if you notice yellowing of the eyes, dark urine, pale stools or unusual tiredness.

Worth knowing: Not suitable in pregnancy or breastfeeding. Check first if you have a thyroid condition or take thyroid medication, sedatives or immunosuppressants. Rare reports of liver injury exist.

Source: NIH NCCIH, Ashwagandha

Also printed as: aspartame, E951, INS 951, phenylalanine

A sweetener made of two amino acids.

What the research says Not an active ingredient

Reviewed repeatedly and kept within approved limits. In 2023 IARC classified it as possibly carcinogenic, while the joint WHO and FAO committee left the acceptable daily intake unchanged.

• Sweetener Approved within set limits. Present for taste, not for any benefit.
• Not for phenylketonuria Contains or releases phenylalanine.

Worth knowing: Must be avoided by people with phenylketonuria, which is why labels carry a phenylalanine warning.

Source: WHO, aspartame assessments

Haematococcus pluvialis

Also printed as: astaxanthin, haematococcus pluvialis, astaxantin

A red pigment from algae, sold for skin and as an antioxidant.

What the research says Limited human evidence

Small trials with limited quality. Not well established.

Worth knowing: Generally well tolerated.

Source: NCBI literature overview

Also printed as: tartrazine, sunset yellow, ponceau 4R, carmoisine, allura red, quinoline yellow, E102, E104, E110

Synthetic colours used to make a product look appealing. They contribute nothing else.

What the research says Not an active ingredient

Six of these carry a mandatory warning in the EU that they "may have an adverse effect on activity and attention in children", following the Southampton study.

• Caution in children Carries a warning about effects on activity and attention in children in some countries.
• Known allergen Has caused allergic reactions in some people.

Worth knowing: Tartrazine in particular can trigger reactions in people sensitive to it, including some with asthma. In a product aimed at children this is worth a second look.

Source: EFSA, food colours and hyperactivity

Bacopa monnieri

Also printed as: bacopa monnieri, brahmi, water hyssop, bacosides, BacoMind, bacopa

Traditional Ayurvedic herb sold for memory. Note that "brahmi" is used in India for both this and gotu kola, which are different plants.

What the research says Limited human evidence

Several small trials report modest improvements on memory tests, generally only after twelve weeks or more of continuous use.

• Commonly upsets digestion Bloating, wind or loose stools are the usual complaints, especially at first.

Worth knowing: Commonly causes stomach upset, especially taken without food.

Source: NCBI literature overview

Vaccinium myrtillus

Also printed as: vaccinium myrtillus, european blueberry, anthocyanosides, bilberry

Sold for eye health, a claim that traces back to a wartime story about pilots rather than to trial data.

What the research says Limited human evidence

Trials for night vision did not confirm the traditional claim. Evidence for eye health generally is weak.

• May increase bleeding Worth knowing before surgery or dental work, and if you take aspirin or a blood thinner.

Worth knowing: May increase bleeding risk at high doses.

Source: NIH NCCIH, Bilberry

Vitamin B7

Also printed as: biotin, vitamin b7, vitamin h, d-biotin, b7

Sold heavily for hair, skin and nails. Deficiency is rare in people eating normally.

What the research says Limited human evidence

Clearly helps the rare genuine deficiency. For hair and nail growth in people who are not deficient, the evidence is thin and mostly from small uncontrolled studies.

• Interferes with blood tests Can produce wrong results on common laboratory tests. Tell any doctor ordering blood work that you take it.

Worth knowing: Important: high-dose biotin interferes with many laboratory blood tests, including thyroid and troponin, and has caused both missed heart attacks and wrong thyroid diagnoses. Tell any doctor ordering blood tests that you take it.

Source: NIH ODS, Biotin

Aerodramus spp.

Also printed as: birds nest, edible birds nest, sarang burung, cubilose, swiftlet nest

A traditional Chinese delicacy, widely produced in Malaysia, sold as a drink or concentrate.

What the research says Limited human evidence

Nutritionally it is mostly protein and carbohydrate. Specific health claims have little clinical support.

• Known allergen Has caused allergic reactions in some people.
• Often mostly sugar Ready-to-drink versions frequently carry more sugar than active ingredient.

Worth knowing: Allergic reactions have been reported. Ready-to-drink versions are often mostly sugar water, so check the sugar figure.

Source: NCBI literature overview

Actaea racemosa

Also printed as: actaea racemosa, cimicifuga racemosa, black cohosh

Sold for menopausal symptoms.

What the research says Limited human evidence

Trial results are mixed; reviews do not find consistent benefit over placebo for hot flushes.

• Reports of liver injury Uncommon but documented cases of liver damage. Stop and seek advice if you notice yellowing of the eyes, dark urine, pale stools or unusual tiredness.

Worth knowing: Reports of liver injury exist, uncommon but serious. Stop and seek advice if you notice yellowing of the eyes or dark urine.

Source: NIH NCCIH, Black Cohosh

Also printed as: caffeine, caffeine anhydrous, guarana, paullinia cupana, green coffee bean extract, kafein

The most used stimulant in the world. Guarana and green coffee extract are caffeine sources and count toward your total.

What the research says Well established

Clearly improves alertness and physical performance in the short term. Tolerance develops.

• Stimulant Adds to caffeine from coffee, tea and energy drinks. Easy to overshoot without noticing.
• Lower limit in pregnancy Allowed, but the recommended ceiling is lower while pregnant.
• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.

Worth knowing: Stacks across coffee, tea, energy drinks and supplements without you noticing. Pure caffeine powder has caused deaths. Avoid combining high doses with other stimulants.

Source: EFSA, caffeine safety

Also printed as: calcium carbonate, calcium citrate, calcium lactate, calcium gluconate, coral calcium, E170, kalsium

The form matters for absorption and for how it sits on the stomach. Carbonate needs stomach acid and is best with food; citrate does not.

What the research says Well established

Supports bone health together with vitamin D, most clearly in people whose intake is low. Supplementing well beyond requirement has not shown added benefit.

• Blocks absorption of other things Reduces how much your body takes up of certain minerals and medicines. Space them a couple of hours apart.

Worth knowing: Reduces absorption of iron, zinc and several antibiotics, so space them apart. Discuss with a doctor if you have had kidney stones.

Source: NIH ODS, Calcium

Elettaria cardamomum

Also printed as: elettaria cardamomum, buah pelaga, green cardamom, cardamom

Usually present for flavour.

What the research says Not an active ingredient

No meaningful health claim at flavouring amounts.

Worth knowing: Not a concern at the amounts used for flavour.

Source: General food composition references

Chondrus crispus

Also printed as: carrageenan, E407, INS 407, irish moss, red seaweed extract, chondrus crispus

Extracted from red seaweed, used to set jellies and thicken drinks.

What the research says Not an active ingredient

Food-grade carrageenan is approved. A degraded form called poligeenan, which is not permitted in food, causes gut inflammation in animals, and the two are frequently confused in online articles.

• Commonly upsets digestion Bloating, wind or loose stools are the usual complaints, especially at first.

Worth knowing: Some people with inflammatory bowel conditions choose to avoid it. Food-grade carrageenan remains approved by food safety authorities.

Source: EFSA, carrageenan re-evaluation

Also printed as: chondroitin sulphate, chondroitin sulfate, chondroitin

Usually extracted from cow or shark cartilage, commonly paired with glucosamine.

What the research says Limited human evidence

Results across trials are inconsistent. Independent trials generally found little benefit.

• Animal derived Comes from an animal source, which matters for halal, vegetarian and vegan diets.
• Affects blood thinners Can change how warfarin and similar medicines work, in either direction. If you take a blood thinner, do not start or stop this without telling your doctor.

Worth knowing: May affect warfarin control. Animal-derived, which matters for halal and vegetarian diets.

Source: NIH NCCIH, Glucosamine and Chondroitin

Also printed as: chromium picolinate, chromium polynicotinate, chromium chloride, chromium

Sold for blood sugar and weight loss.

What the research says Limited human evidence

Reviews of trials for weight loss and glucose control find effects that are either absent or too small to matter clinically.

Worth knowing: Generally well tolerated at usual supplement doses. Check with a doctor if you take diabetes medication.

Source: NIH ODS, Chromium

Also printed as: citric acid, E330, INS 330, sodium citrate, asid sitrik

Provides tartness and helps preserve. Made by fermentation rather than squeezed from fruit.

What the research says Not an active ingredient

Not an active ingredient.

Worth knowing: Not generally a concern.

Source: EFSA additive assessments

Citrus spp.

Also printed as: citrus bioflavonoids, hesperidin, naringin, polymethoxylated flavones, citrus peel, bitter orange, citrus aurantium, synephrine

A source of flavonoids. Note that bitter orange, sold for weight loss, contains synephrine and is a different proposition from ordinary citrus bioflavonoids.

What the research says Limited human evidence

Flavonoid evidence is limited. Synephrine-containing bitter orange has been associated with cardiovascular adverse events.

• Stimulant Adds to caffeine from coffee, tea and energy drinks. Easy to overshoot without noticing.

Worth knowing: Avoid bitter orange or synephrine if you have heart problems or high blood pressure, and do not combine it with caffeine for weight loss.

Source: NIH NCCIH, Bitter Orange

Ubiquinone

Also printed as: coq10, co-q10, ubiquinone, ubiquinol, coenzyme q10

Made by the body. Ubiquinol is the reduced form and is absorbed somewhat better.

What the research says Limited human evidence

Studied most for statin-related muscle symptoms, where results have been mixed and largely unconvincing. Some evidence in heart failure.

• Affects blood thinners Can change how warfarin and similar medicines work, in either direction. If you take a blood thinner, do not start or stop this without telling your doctor.

Worth knowing: May reduce the effect of warfarin.

Source: NIH NCCIH, Coenzyme Q10

Also printed as: hydrolysed collagen, hydrolyzed collagen, collagen peptides, marine collagen, bovine collagen, type i collagen, type ii collagen, type iii collagen, kolagen

Protein broken into peptides. Once swallowed it is digested into amino acids like any other protein; the idea that it travels to your skin as collagen is not how digestion works.

What the research says Limited human evidence

Some small trials report modest changes in skin elasticity and joint comfort. Many are industry-funded, and the mechanism is still debated.

• Animal derived Comes from an animal source, which matters for halal, vegetarian and vegan diets.

Worth knowing: Marine collagen is a fish product and is a concern if you have a fish allergy. Bovine and porcine sources matter for halal and for dietary choice.

Source: NCBI literature overview

Vaccinium macrocarpon

Also printed as: vaccinium macrocarpon, proanthocyanidins, PAC, cranberry extract, cranberry

Sold to prevent urinary tract infections. The compounds credited are proanthocyanidins.

What the research says Some human evidence

Reviews find a modest reduction in recurrent UTIs in women prone to them. It is prevention, not treatment: it does not treat an infection you already have.

• Affects blood thinners Can change how warfarin and similar medicines work, in either direction. If you take a blood thinner, do not start or stop this without telling your doctor.

Worth knowing: May interact with warfarin. Juice versions often carry a lot of sugar.

Source: NIH NCCIH, Cranberry

Also printed as: creatine monohydrate, creatine HCl, kre-alkalyn, creatine

One of the best-evidenced sports supplements there is. Monohydrate is the form nearly all research used.

What the research says Well established

Consistently improves strength and power output in training. The evidence here is genuinely strong, unusually so for this aisle.

Worth knowing: Causes some water retention. People with kidney disease should check with a doctor first.

Source: NCBI literature overview

Echinacea purpurea

Also printed as: echinacea purpurea, echinacea angustifolia, coneflower, echinacea

Sold for colds. Preparations vary enormously between species, plant part and extraction method.

What the research says Limited human evidence

Reviews find inconsistent results. Any effect on preventing or shortening colds appears small and unreliable.

• Check if immune-suppressed Worth asking about if you have an autoimmune condition or take immunosuppressants.
• Known allergen Has caused allergic reactions in some people.

Worth knowing: People allergic to daisies, ragweed or marigolds may react. Check first if you have an autoimmune condition.

Source: NIH NCCIH, Echinacea

Sambucus nigra

Also printed as: sambucus nigra, black elder, sambucol, elderberry, elder

Sold for colds and flu, usually as a syrup or lozenge.

What the research says Limited human evidence

A few small trials report shorter symptoms. Studies are small and several were industry-funded, so the evidence is weak.

Worth knowing: Raw or unripe elderberries are toxic and must be cooked. Commercial preparations are processed.

Source: NIH NCCIH, Elderberry

Oenothera biennis

Also printed as: oenothera biennis, EPO, gamma-linolenic acid, GLA, evening primrose

A source of gamma-linolenic acid, sold for eczema and premenstrual symptoms.

What the research says Limited human evidence

Reviews of eczema trials found no meaningful benefit. Evidence for other uses is weak.

• May increase bleeding Worth knowing before surgery or dental work, and if you take aspirin or a blood thinner.

Worth knowing: May increase bleeding risk. Check first if you have a seizure disorder or take blood thinners.

Source: NIH NCCIH, Evening Primrose Oil

Vitamin B9

Also printed as: folic acid, folate, vitamin b9, b9, methylfolate, 5-MTHF, L-methylfolate, folacin

Folate is the form in food, folic acid the synthetic form in supplements and fortified flour.

What the research says Well established

One of the strongest cases in all of supplementation: folic acid before and during early pregnancy clearly reduces neural tube defects.

• Can hide a B12 deficiency High intakes can mask a vitamin B12 deficiency while nerve damage quietly continues.

Worth knowing: High folic acid intake can mask a vitamin B12 deficiency while nerve damage continues. Relevant if you are over 50, vegan, or take metformin long-term.

Source: NIH ODS, Folate

Allium sativum

Also printed as: allium sativum, aged garlic extract, allicin, garlic oil, bawang putih, garlic

Sold for cholesterol and blood pressure. Allicin, the compound usually credited, is unstable and varies greatly between preparations.

What the research says Limited human evidence

Trials show small reductions in blood pressure. Effects on cholesterol have been inconsistent.

• May increase bleeding Worth knowing before surgery or dental work, and if you take aspirin or a blood thinner.

Worth knowing: Can increase bleeding risk, relevant with blood thinners or before surgery.

Source: NIH NCCIH, Garlic

Also printed as: gelatin, gelatine, bovine gelatin, porcine gelatin, fish gelatin, E441, gelatin capsule

Made from animal collagen. Most capsule shells are gelatin unless stated otherwise.

What the research says Not an active ingredient

Not an active ingredient.

• Animal derived Comes from an animal source, which matters for halal, vegetarian and vegan diets.
• Check the halal status Source varies by manufacturer and is easy to miss, particularly in a capsule shell.

Worth knowing: Source matters. Porcine gelatin is not halal, and a capsule shell is easy to overlook when checking a product. Vegetarian capsules use HPMC instead.

Source: General food composition references

Zingiber officinale

Also printed as: zingiber officinale, gingerol, halia, ginger root, ginger

Used both as food and as an extract, most credibly for nausea.

What the research says Some human evidence

Reasonable trial evidence for nausea in pregnancy and after surgery. Evidence for joint pain is weaker.

• May increase bleeding Worth knowing before surgery or dental work, and if you take aspirin or a blood thinner.

Worth knowing: May increase bleeding risk at high doses. Generally considered safe in pregnancy at food-like amounts, but check with a midwife or doctor.

Source: NIH NCCIH, Ginger

Ginkgo biloba

Also printed as: ginkgo biloba, ginko, EGb 761, ginkgo flavone glycosides, maidenhair tree, ginkgo

Leaf extract sold for memory and circulation. Research overwhelmingly uses one standardised extract, EGb 761.

What the research says Some human evidence

A very large trial found it did not prevent dementia in older adults. Some evidence exists for symptoms in people already diagnosed, and the picture is mixed.

• May increase bleeding Worth knowing before surgery or dental work, and if you take aspirin or a blood thinner.
• Affects blood thinners Can change how warfarin and similar medicines work, in either direction. If you take a blood thinner, do not start or stop this without telling your doctor.

Worth knowing: Increases bleeding risk, which matters with warfarin, aspirin or before surgery. Raw ginkgo seeds are toxic and are not the same as leaf extract.

Source: NIH NCCIH, Ginkgo

Panax ginseng

Also printed as: panax ginseng, korean ginseng, red ginseng, asian ginseng, panax quinquefolius, american ginseng, ginsenosides, ginseng

Panax ginseng is the plant most research refers to. Siberian ginseng and Indian ginseng are entirely different plants despite the shared word.

What the research says Some human evidence

Trials for fatigue and general wellbeing report small effects, with inconsistent results and variable extract quality across studies.

• Affects blood thinners Can change how warfarin and similar medicines work, in either direction. If you take a blood thinner, do not start or stop this without telling your doctor.
• Affects blood sugar Can lower blood sugar. If you take diabetes medication, this can stack with it.

Worth knowing: Can affect blood sugar and may interact with warfarin and with diabetes medication. May cause difficulty sleeping.

Source: NIH NCCIH, Asian Ginseng

Also printed as: glucosamine sulphate, glucosamine sulfate, glucosamine hydrochloride, glucosamine HCl, N-acetylglucosamine, glucosamine

Usually made from shellfish shells. Sulphate and hydrochloride forms have been studied differently.

What the research says Limited human evidence

Large independent trials mostly found it no better than placebo for knee osteoarthritis pain. Some industry-funded trials of the sulphate form were more positive.

• Shellfish derived Usually made from shellfish, so relevant if you have a shellfish allergy.
• Affects blood thinners Can change how warfarin and similar medicines work, in either direction. If you take a blood thinner, do not start or stop this without telling your doctor.

Worth knowing: Usually derived from shellfish, so it matters if you have a shellfish allergy. May affect warfarin control.

Source: NIH NCCIH, Glucosamine and Chondroitin

Centella asiatica

Also printed as: centella asiatica, pegaga, gotu kola, asiaticoside, madecassoside, indian pennywort

Eaten as a vegetable across Southeast Asia and sold as an extract for circulation and skin.

What the research says Limited human evidence

Some trial support for chronic venous insufficiency. Evidence for memory and skin claims is thin.

• Reports of liver injury Uncommon but documented cases of liver damage. Stop and seek advice if you notice yellowing of the eyes, dark urine, pale stools or unusual tiredness.
• Not suitable in pregnancy Avoid while pregnant or breastfeeding, or while trying to conceive, unless a doctor has said otherwise.

Worth knowing: Rare reports of liver problems with prolonged use. Avoid in pregnancy.

Source: NIH NCCIH, Gotu Kola

Vitis vinifera

Also printed as: vitis vinifera, OPC, oligomeric proanthocyanidins, grape seed, grapeseed

A source of proanthocyanidins, sold for circulation and as an antioxidant.

What the research says Limited human evidence

Some small trials suggest modest blood pressure effects. Evidence overall is limited.

• May increase bleeding Worth knowing before surgery or dental work, and if you take aspirin or a blood thinner.

Worth knowing: May increase bleeding risk with blood thinners.

Source: NIH NCCIH, Grape Seed Extract

Camellia sinensis

Also printed as: camellia sinensis, EGCG, epigallocatechin gallate, green tea catechins, green tea extract, teh hijau

Concentrated catechins, mostly EGCG. Drinking green tea and taking a concentrated extract are not the same exposure.

What the research says Limited human evidence

Weight loss trials show effects too small to matter in practice. Drinking the tea has a better safety record than the concentrated extract.

• Reports of liver injury Uncommon but documented cases of liver damage. Stop and seek advice if you notice yellowing of the eyes, dark urine, pale stools or unusual tiredness.

Worth knowing: Concentrated extracts have caused liver injury, particularly taken on an empty stomach. Stop and seek advice if you notice dark urine, pale stools or yellowing of the eyes.

Source: NIH LiverTox, Green Tea

Also printed as: sodium hyaluronate, hyaluronan, HA, hyaluronic acid

Naturally present in skin and joints. Sold both as a cream and as something to swallow.

What the research says Limited human evidence

Topical and injected uses have better support than oral. Oral trials are small.

Worth knowing: Generally well tolerated.

Source: NCBI literature overview

Also printed as: inulin, fructooligosaccharides, FOS, chicory root fibre, oligofructose, prebiotic fibre

A fibre that feeds gut bacteria. Also used to add bulk and a little sweetness.

What the research says Limited human evidence

Genuinely a fibre and does change gut bacteria. Specific health outcomes are less well established.

Worth knowing: Commonly causes bloating and wind, particularly when you first start or if you have IBS.

Source: NCBI literature overview

Also printed as: potassium iodide, potassium iodate, sodium iodide, kelp, iodine, iodin

Needed to make thyroid hormone. Most Malaysian table salt is iodised, which is why deficiency became uncommon.

What the research says Well established

Correcting deficiency prevents goitre and, in pregnancy, protects infant brain development. Supplementing beyond requirement does not help the thyroid and can harm it.

• Affects the thyroid Relevant if you have a thyroid condition or take thyroid medication.
• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.

Worth knowing: Both too little and too much cause thyroid problems. If you have a thyroid condition, do not take iodine or kelp without medical advice.

Source: NIH ODS, Iodine

Also printed as: ferrous fumarate, ferrous sulphate, ferrous sulfate, ferrous gluconate, ferric pyrophosphate, iron bisglycinate, carbonyl iron, zat besi, iron

The figure that matters is elemental iron, which is a fraction of the compound weight: 325mg of ferrous sulphate is about 65mg of iron.

What the research says Well established

Treating iron deficiency anaemia clearly works. Taking iron without a deficiency has no benefit and real downsides.

• Dangerous to children A serious poisoning risk for young children at adult doses. Keep well out of reach.
• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.
• Blocks absorption of other things Reduces how much your body takes up of certain minerals and medicines. Space them a couple of hours apart.

Worth knowing: Do not supplement iron without knowing you are deficient. Iron overload damages organs, and iron tablets are a leading cause of poisoning in young children. Keep out of reach.

Source: NIH ODS, Iron

Labisia pumila

Also printed as: labisia pumila, selusoh fatimah, rumput fatimah, kacip fatimah

A Malaysian plant traditionally used by women, often marketed as a counterpart to tongkat ali.

What the research says Limited human evidence

Research is mostly laboratory and animal work, with a small number of human trials. There is not enough clinical evidence to say what it does in people.

• Not suitable in pregnancy Avoid while pregnant or breastfeeding, or while trying to conceive, unless a doctor has said otherwise.

Worth knowing: Avoid in pregnancy. Because it has been studied for oestrogen-related effects, check with a doctor if you have a hormone-sensitive condition.

Source: NCBI literature overview

Also printed as: theanine, l-theanine, suntheanine

An amino acid found in tea, sold for calm focus, often paired with caffeine.

What the research says Limited human evidence

Small trials suggest modest effects on stress and attention. Evidence is limited.

Worth knowing: Generally well tolerated.

Source: NCBI literature overview

Also printed as: lutein, zeaxanthin, marigold extract, tagetes erecta, lutein esters

Concentrates in the retina. Usually extracted from marigold.

What the research says Some human evidence

Part of the AREDS2 formula, which showed benefit specifically for slowing advanced age-related macular degeneration in people who already have intermediate disease.

Worth knowing: Generally well tolerated.

Source: NIH NEI, AREDS2

Lepidium meyenii

Also printed as: lepidium meyenii, peruvian ginseng, maca root, maca

A Peruvian root sold for energy and libido.

What the research says Limited human evidence

A small number of small trials. Reviews conclude the evidence is insufficient to draw conclusions.

• Affects the thyroid Relevant if you have a thyroid condition or take thyroid medication.

Worth knowing: Generally well tolerated. Check first if you have a thyroid condition, as it contains goitrogens.

Source: NCBI literature overview

Also printed as: magnesium oxide, magnesium citrate, magnesium glycinate, magnesium bisglycinate, magnesium malate, magnesium threonate, magnesium chloride, magnesium sulphate, E530

Forms differ substantially. Oxide is cheap and poorly absorbed and acts largely as a laxative; citrate and glycinate are absorbed better.

What the research says Some human evidence

Corrects deficiency. Evidence for sleep and muscle cramps in people who are not deficient is weak and inconsistent, despite how it is marketed.

• Commonly upsets digestion Bloating, wind or loose stools are the usual complaints, especially at first.
• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.

Worth knowing: The common side effect is loose stools, particularly with oxide and citrate. People with reduced kidney function should check first.

Source: NIH ODS, Magnesium

Also printed as: magnesium stearate, stearic acid, vegetable stearate, E470b

Stops tablet ingredients sticking to manufacturing equipment. Present in very small amounts.

What the research says Not an active ingredient

Not an active ingredient. The online claims that it suppresses the immune system trace back to a single cell study and do not reflect how it behaves in people.

Worth knowing: Not a concern at the amounts used. May be animal or plant derived, which matters for halal and vegetarian diets.

Source: General pharmaceutical excipient references

Also printed as: maltodextrin, corn syrup solids, glucose polymer, tapioca maltodextrin

A processed starch used as a carrier and bulking agent. It is often the largest ingredient by weight in a powder.

What the research says Not an active ingredient

Not an active ingredient. Worth noticing because it raises blood sugar quickly, more so than table sugar by some measures.

• Raises blood sugar Worth noticing if you are managing blood sugar.

Worth knowing: Relevant if you are managing blood sugar. If it appears first on the list, most of what you are buying is this.

Source: General food composition references

Also printed as: melatonin, N-acetyl-5-methoxytryptamine

A hormone, not a herb, despite being sold alongside them. In Malaysia it is a controlled medicine, not a general supplement.

What the research says Some human evidence

Reasonable evidence for jet lag and for shifting sleep timing. Less convincing as a general sleeping aid.

• Prescription-only in Malaysia Controlled here, whatever the rules are in the country it was bought from. Products brought in from abroad are not approved for sale in Malaysia.
• Causes drowsiness Do not drive or operate machinery until you know how it affects you.
• Not suitable in pregnancy Avoid while pregnant or breastfeeding, or while trying to conceive, unless a doctor has said otherwise.

Worth knowing: In Malaysia melatonin is a scheduled poison and requires a prescription. Products bought online from abroad are not approved for sale here. Causes drowsiness; do not drive after taking it.

Source: NIH NCCIH, Melatonin

Silybum marianum

Also printed as: silybum marianum, silymarin, silibinin, silybin, milk thistle

Sold for liver support. Silymarin is the active fraction.

What the research says Limited human evidence

Despite long use, trials in liver disease have been inconsistent and largely have not shown clear benefit on meaningful outcomes.

• Known allergen Has caused allergic reactions in some people.

Worth knowing: Generally well tolerated. People allergic to ragweed, daisies or chrysanthemums may react.

Source: NIH NCCIH, Milk Thistle

Orthosiphon stamineus

Also printed as: orthosiphon stamineus, orthosiphon aristatus, java tea, cats whiskers, misai kucing, kumis kucing

A Malaysian and Indonesian plant drunk as a tea, traditionally used for the kidneys and urinary tract.

What the research says Limited human evidence

Mostly laboratory and animal research. Human trials are few and small, so clinical effects are not established.

• Not safe with reduced kidney function Can build to dangerous levels if the kidneys are not clearing it normally, or alongside certain blood pressure medicines.

Worth knowing: It has a diuretic effect. Check with a doctor if you take diuretics or have kidney disease.

Source: NCBI literature overview

Various

Also printed as: acai, maqui, chokeberry, aronia, elderberry blend, mixed berries, berry blend, blackcurrant, blueberry extract

A blend, often present partly for colour and flavour. Blends rarely state how much of each berry is included.

What the research says Limited human evidence

Berries contain polyphenols, but a blend at an unstated dose cannot be compared to any trial.

Worth knowing: Not generally a concern. If the amount of each component is not stated, no claim about it can be checked.

Source: General food composition references

Moringa oleifera

Also printed as: moringa oleifera, drumstick tree, kelor, merunggai, moringa

Leaf powder used as both food and supplement, sold with a very wide range of claims.

What the research says Limited human evidence

Mostly laboratory and animal work. Human trials are few and small, so clinical effects are not established.

• Not suitable in pregnancy Avoid while pregnant or breastfeeding, or while trying to conceive, unless a doctor has said otherwise.

Worth knowing: Avoid root and root bark, which contain more hazardous compounds than the leaf. Avoid in pregnancy.

Source: NCBI literature overview

Methylsulfonylmethane

Also printed as: methylsulfonylmethane, dimethyl sulfone, MSM

Sold for joint pain, often alongside glucosamine.

What the research says Limited human evidence

A small number of small trials suggest possible benefit. Evidence is limited.

Worth knowing: Generally well tolerated; may cause stomach upset.

Source: NCBI literature overview

N-acetylcysteine

Also printed as: n-acetylcysteine, n-acetyl cysteine, acetylcysteine, NAC

Used medically for paracetamol overdose and to thin mucus. Also sold as a general supplement.

What the research says Some human evidence

Strong evidence in its medical uses. Evidence for general supplement claims is much weaker.

• Also used as a medicine This is a medicine in some countries and a supplement in others. Treat it with the same care as a medicine.

Worth knowing: This is a medicine in several countries. Check with a pharmacist, particularly if you take nitroglycerin or blood thinners.

Source: NCBI literature overview

Also printed as: natural flavour, natural flavor, artificial flavour, artificial flavor, flavouring, perisa, nature identical flavour

A catch-all term. A single entry can cover dozens of compounds, and manufacturers are not required to break it down.

What the research says Not an active ingredient

Not an active ingredient. "Natural" here is a regulatory category about origin, not a statement about health.

Worth knowing: Not usually a concern, but it is genuinely opaque, which is worth knowing when a label otherwise looks very clean.

Source: General food labelling references

EPA and DHA

Also printed as: fish oil, EPA, DHA, eicosapentaenoic acid, docosahexaenoic acid, omega 3, omega-3, cod liver oil, algal oil

The figure that matters is combined EPA and DHA, not the weight of the fish oil capsule. A 1000mg capsule often contains only about 300mg of EPA plus DHA.

What the research says Well established

High-dose prescription forms reduce triglycerides. General supplementation for heart disease prevention has produced mixed results in large trials.

• May increase bleeding Worth knowing before surgery or dental work, and if you take aspirin or a blood thinner.
• Fish derived A fish product, so relevant if you have a fish allergy.

Worth knowing: High doses can increase bleeding risk. Cod liver oil also contains vitamin A, which has its own upper limit, so do not treat it as interchangeable with fish oil.

Source: NIH ODS, Omega-3

Also printed as: pectin, E440, INS 440, apple pectin, citrus pectin

A fibre from fruit used to set jellies. A plant-based alternative to gelatin.

What the research says Not an active ingredient

Not an active ingredient at the amounts used for setting.

Worth knowing: Not generally a concern.

Source: EFSA additive assessments

Pinus pinaster

Also printed as: pinus pinaster, pycnogenol, maritime pine, french maritime pine, pine bark

Usually sold as the branded extract Pycnogenol.

What the research says Limited human evidence

Reviews of trials across several conditions conclude the evidence is insufficient, with small and poorly designed studies.

• Check if immune-suppressed Worth asking about if you have an autoimmune condition or take immunosuppressants.

Worth knowing: Check first if you have an autoimmune condition or take immunosuppressants.

Source: NCBI literature overview

Piper nigrum

Also printed as: piper nigrum, black pepper extract, BioPerine, bioperine, piperine

Added to increase absorption of other ingredients, most commonly curcumin.

What the research says Some human evidence

It does measurably raise blood levels of several compounds taken alongside it. That is the claim, and it holds up.

• Interacts with many medicines This one is known to change how a long list of prescription medicines work. Check with a pharmacist before taking it with anything else.

Worth knowing: The same mechanism raises blood levels of some prescription medicines, which can be a problem rather than a benefit. Worth a pharmacist check if you take regular medication.

Source: NCBI literature overview

Punica granatum

Also printed as: punica granatum, delima, punicalagin, ellagic acid, pomegranate

Fruit and peel extract, a source of polyphenols.

What the research says Limited human evidence

Small trials report modest effects on blood pressure markers. Broader claims are not well supported.

• Affects blood thinners Can change how warfarin and similar medicines work, in either direction. If you take a blood thinner, do not start or stop this without telling your doctor.

Worth knowing: May interact with blood pressure medication and with some drugs processed by the liver.

Source: NIH NCCIH, Pomegranate

Also printed as: potassium chloride, potassium citrate, potassium gluconate, E508, potassium, kalium

Most people get far less than recommended because it comes mainly from fruit and vegetables.

What the research says Some human evidence

Higher dietary potassium is associated with lower blood pressure. Supplements are capped at low doses in most countries for safety reasons.

• Not safe with reduced kidney function Can build to dangerous levels if the kidneys are not clearing it normally, or alongside certain blood pressure medicines.

Worth knowing: Dangerous in people with reduced kidney function or on ACE inhibitors, ARBs or potassium-sparing diuretics. Do not supplement without medical advice.

Source: NIH ODS, Potassium

Also printed as: potassium sorbate, sorbic acid, E202, E200, INS 202

A common preservative against mould and yeast.

What the research says Not an active ingredient

Approved within limits and generally regarded as one of the better tolerated preservatives.

Worth knowing: Not generally a concern at the amounts used.

Source: EFSA additive assessments

Also printed as: lactobacillus, bifidobacterium, saccharomyces boulardii, L. rhamnosus, L. acidophilus, B. lactis, CFU, probiotic, live cultures

Effects are strain-specific. "Contains lactobacillus" tells you almost nothing, because different strains do different things.

What the research says Some human evidence

Good evidence for specific strains in specific situations, notably antibiotic-associated diarrhoea. Generic claims about gut health are not well supported.

• Check if immune-suppressed Worth asking about if you have an autoimmune condition or take immunosuppressants.

Worth knowing: People who are seriously ill or immunocompromised should check with a doctor, as infections have occurred in rare cases.

Source: NIH NCCIH, Probiotics

Plantago ovata

Also printed as: plantago ovata, ispaghula, psyllium husk, isabgol, psyllium

A bulk-forming fibre.

What the research says Some human evidence

Good evidence for constipation and modest reductions in LDL cholesterol.

Worth knowing: Must be taken with plenty of water or it can cause obstruction. Space it apart from medication, as it can reduce absorption.

Source: NCBI literature overview

Also printed as: resveratrol, trans-resveratrol, polygonum cuspidatum, japanese knotweed

The compound behind the red wine headlines.

What the research says Limited human evidence

Laboratory results have not translated. Human trials have largely failed to show the effects suggested by cell and animal work.

• May increase bleeding Worth knowing before surgery or dental work, and if you take aspirin or a blood thinner.

Worth knowing: May increase bleeding risk and interact with drugs processed by the liver.

Source: NCBI literature overview

Rhodiola rosea

Also printed as: rhodiola rosea, golden root, arctic root, rosavin, salidroside, rhodiola

Sold for fatigue and stress resilience.

What the research says Limited human evidence

Small trials suggest possible benefit for fatigue, but studies are few, small and of variable quality.

Worth knowing: May be stimulating; some people find it disturbs sleep. Check first if you have bipolar disorder.

Source: NIH NCCIH, Rhodiola

Salvia rosmarinus

Also printed as: rosmarinus officinalis, salvia rosmarinus, rosemary extract, rosmarinic acid, E392, rosemary

Usually present as a natural antioxidant to stop oils in a product going rancid, rather than as an active ingredient.

What the research says Not an active ingredient

Effective at its actual job, which is preserving the product. Health claims at the amounts used are not supported.

Worth knowing: Not a concern at the amounts used for preservation.

Source: EFSA, rosemary extracts as antioxidant

Also printed as: royal jelly, 10-HDA, jeli diraja, propolis, bee pollen

Bee products sold with broad wellness claims.

What the research says Limited human evidence

Limited human trial evidence for the claims made.

• Bee product Bee products have caused severe reactions, including in people with asthma.
• Not suitable in pregnancy Avoid while pregnant or breastfeeding, or while trying to conceive, unless a doctor has said otherwise.

Worth knowing: Has caused severe allergic reactions, including asthma attacks and anaphylaxis, particularly in people with existing allergies or asthma.

Source: NCBI literature overview

Crocus sativus

Also printed as: crocus sativus, kesar, zafaran, safranal, crocin, affron, saffron

The spice, as a standardised extract. Expensive, and adulteration is common.

What the research says Limited human evidence

Several small trials report improvements in mood scores. Studies are small, often industry-funded, and mostly from one or two research groups.

• Not suitable in pregnancy Avoid while pregnant or breastfeeding, or while trying to conceive, unless a doctor has said otherwise.

Worth knowing: Avoid high doses in pregnancy. Check first if you take antidepressants.

Source: NCBI literature overview

Sodium chloride

Also printed as: sea salt, sodium chloride, garam laut, himalayan salt, rock salt, salt

Used for taste and sometimes as an electrolyte. Sea salt and table salt are nutritionally almost identical.

What the research says Not an active ingredient

Not an active ingredient at the amounts used for flavour.

• Adds sodium Worth noticing if you are watching salt for blood pressure.

Worth knowing: Relevant if you are watching sodium for blood pressure, particularly in electrolyte drinks.

Source: General food composition references

Serenoa repens

Also printed as: serenoa repens, sabal, saw palmetto

Sold for prostate symptoms and, more recently, hair loss.

What the research says Limited human evidence

The largest and best-conducted trials found it worked no better than placebo for prostate symptoms, despite earlier promising smaller studies.

• Interferes with blood tests Can produce wrong results on common laboratory tests. Tell any doctor ordering blood work that you take it.

Worth knowing: Can interfere with PSA test results, which matters for prostate cancer screening. Tell your doctor if you take it.

Source: NIH NCCIH, Saw Palmetto

Also printed as: selenomethionine, sodium selenite, sodium selenate, selenium yeast, selenium

Needed in very small amounts. The gap between enough and too much is narrower than for most nutrients.

What the research says Some human evidence

Corrects deficiency. Large trials of supplementation in well-nourished people, including for cancer prevention, did not show the hoped-for benefit.

• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.

Worth knowing: Chronic excess causes hair loss, nail changes and a garlic odour on the breath. Stay well below the upper limit.

Source: NIH ODS, Selenium

Also printed as: silicon dioxide, silica, E551, INS 551, colloidal silicon dioxide

Stops powder clumping so it flows through machinery.

What the research says Not an active ingredient

Not an active ingredient. Approved as an additive.

Worth knowing: Not generally a concern at the amounts used.

Source: EFSA additive assessments

Also printed as: sodium benzoate, benzoic acid, E211, E210, INS 211

Stops mould and bacteria growing, used mostly in acidic products.

What the research says Not an active ingredient

Approved within limits. In the presence of vitamin C it can form small amounts of benzene, which is why drink formulations are watched.

• Watch alongside vitamin C Can form trace benzene in the presence of vitamin C, which is why drink formulations are monitored.

Worth knowing: Worth noticing when a product contains both this and vitamin C.

Source: EFSA additive assessments

Also printed as: sorbitol, maltitol, xylitol, erythritol, isomalt, mannitol, E420, E965, E967

Sweeteners that provide some calories and are used for bulk as well as sweetness.

What the research says Not an active ingredient

Well established as sweeteners. Erythritol has recently attracted research attention regarding cardiovascular markers, which is ongoing.

• Commonly upsets digestion Bloating, wind or loose stools are the usual complaints, especially at first.

Worth knowing: Commonly cause bloating, wind and a laxative effect in quantity. Xylitol is highly toxic to dogs.

Source: EFSA additive assessments

Arthrospira platensis

Also printed as: arthrospira platensis, arthrospira maxima, blue-green algae, spirulina

A blue-green algae sold as a protein and nutrient source.

What the research says Limited human evidence

Nutritionally it does contain protein and micronutrients. Specific health claims are not well supported by trials.

• Contamination risk if poorly sourced Has been found carrying heavy metals or toxins when sourced badly. Buy registered products.
• Not for phenylketonuria Contains or releases phenylalanine.
• Check if immune-suppressed Worth asking about if you have an autoimmune condition or take immunosuppressants.

Worth knowing: Can be contaminated with microcystins or heavy metals if poorly sourced. Avoid if you have phenylketonuria or an autoimmune condition.

Source: NIH NCCIH, Blue-Green Algae

Hypericum perforatum

Also printed as: hypericum perforatum, hypericin, hyperforin, st johns wort, st. johns wort, saint johns wort

Sold for low mood. One of the few botanicals with genuinely substantial trial evidence, and also one of the most dangerous for drug interactions.

What the research says Some human evidence

Trials in mild to moderate depression found it better than placebo and broadly comparable to standard antidepressants, with fewer side effects.

• Interacts with many medicines This one is known to change how a long list of prescription medicines work. Check with a pharmacist before taking it with anything else.
• Not suitable in pregnancy Avoid while pregnant or breastfeeding, or while trying to conceive, unless a doctor has said otherwise.

Worth knowing: Interacts with a very large number of medicines, including the contraceptive pill, warfarin, HIV medication, transplant drugs and antidepressants. Combining it with an SSRI can cause serotonin syndrome. Do not take it without telling your doctor or pharmacist.

Source: NIH NCCIH, St. John’s Wort

Stevia rebaudiana

Also printed as: stevia, steviol glycosides, rebaudioside A, reb a, E960, INS 960, stevia rebaudiana

Extracted from a leaf, though the purified glycoside is a long way from the plant.

What the research says Not an active ingredient

Approved within set limits.

• Sweetener Approved within set limits. Present for taste, not for any benefit.

Worth knowing: Considered safe within approved limits. Some find it has a bitter aftertaste.

Source: EFSA sweetener assessments

Also printed as: sucralose, E955, splenda, INS 955

A sweetener about 600 times sweeter than sugar, used in tiny amounts.

What the research says Not an active ingredient

Approved by food safety authorities worldwide. Research on long-term effects on gut bacteria continues and is not settled.

• Sweetener Approved within set limits. Present for taste, not for any benefit.

Worth knowing: Within approved limits it is considered safe. Some people report digestive upset.

Source: EFSA / FDA sweetener assessments

Also printed as: titanium dioxide, E171, INS 171, CI 77891

Used to make tablets and coatings opaque white.

What the research says Not an active ingredient

The European Food Safety Authority concluded in 2021 that it could no longer be considered safe as a food additive, citing genotoxicity concerns, and the EU banned it in food in 2022. Other authorities, including the UK and US, reviewed the same evidence and kept it permitted.

• Regulators disagree Permitted in some countries and banned in others, which is worth knowing even where it is legal.

Worth knowing: Regulators disagree about this one. It is banned in food across the EU and still permitted elsewhere. Worth knowing it is there, since it does nothing except make the product look white.

Source: EFSA, titanium dioxide 2021 opinion

Eurycoma longifolia

Also printed as: eurycoma longifolia, longjack, pasak bumi, malaysian ginseng, tongkat ali, physta, eurycomanone

A Malaysian plant sold widely for energy, testosterone and male fertility. Water-soluble standardised extracts are what most research uses.

What the research says Limited human evidence

Small trials, several conducted in Malaysia, report modest changes in testosterone and self-reported stress in specific groups. Studies are small and often industry-linked; the evidence is suggestive rather than settled.

• Not suitable in pregnancy Avoid while pregnant or breastfeeding, or while trying to conceive, unless a doctor has said otherwise.
• Commonly adulterated Products in this category have repeatedly been found containing undeclared pharmaceutical drugs. Buy only registered products and check the MAL number.

Worth knowing: Avoid in pregnancy. Some products have been found adulterated with pharmaceutical erectile dysfunction drugs, so buy from registered sources. Check with a pharmacist if you take blood pressure or diabetes medication.

Source: NIH NCCIH, Eurycoma longifolia

Curcuma longa

Also printed as: curcuma longa, curcumin, curcuminoids, kunyit, Meriva, BCM-95, Theracurmin, longvida, E100

Curcumin is the compound studied; turmeric powder is only about 3% curcumin. Curcumin on its own is poorly absorbed, which is why formulations add piperine or use special carriers.

What the research says Some human evidence

Trials in knee osteoarthritis report pain improvements against placebo, though many are small. Broader claims across other conditions are not well supported.

• May increase bleeding Worth knowing before surgery or dental work, and if you take aspirin or a blood thinner.
• Reports of liver injury Uncommon but documented cases of liver damage. Stop and seek advice if you notice yellowing of the eyes, dark urine, pale stools or unusual tiredness.
• Affects blood thinners Can change how warfarin and similar medicines work, in either direction. If you take a blood thinner, do not start or stop this without telling your doctor.

Worth knowing: Can increase bleeding risk and may worsen gallbladder problems. Rare but real reports of liver injury, more often with high-absorption formulations. Check if you take blood thinners.

Source: NIH NCCIH, Turmeric

Valeriana officinalis

Also printed as: valeriana officinalis, valerian root, valerian

Sold for sleep and anxiety.

What the research says Limited human evidence

Trial results are mixed and many studies are of poor quality. Reviews conclude the evidence does not clearly support it.

• Causes drowsiness Do not drive or operate machinery until you know how it affects you.

Worth knowing: Can add to the effect of alcohol and sedatives. Do not drive if it makes you drowsy.

Source: NIH NCCIH, Valerian

Retinol

Also printed as: retinol, retinyl palmitate, retinyl acetate, beta-carotene, betacarotene, provitamin a, E160a, vitamin a

Comes as preformed vitamin A (retinol, from animal sources) or as beta-carotene, which the body converts as needed. The two behave quite differently at high intakes.

What the research says Well established

Essential for vision and immune function, and correcting deficiency matters a great deal. Beta-carotene supplements were found to increase lung cancer risk in smokers in two large trials.

• Not suitable in pregnancy Avoid while pregnant or breastfeeding, or while trying to conceive, unless a doctor has said otherwise.
• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.

Worth knowing: High-dose preformed vitamin A causes birth defects. Not to be taken in pregnancy without medical advice. Smokers should avoid beta-carotene supplements.

Source: NIH ODS, Vitamin A

Thiamine

Also printed as: thiamine, thiamin, thiamine hydrochloride, thiamine mononitrate, benfotiamine, vitamin b1, b1

Needed to turn carbohydrate into energy. Water-soluble, so it is not stored in any quantity.

What the research says Well established

Treats and prevents deficiency, which still occurs with heavy alcohol use and after some surgeries. No reliable benefit shown for supplementing beyond requirement.

Worth knowing: Generally well tolerated.

Source: NIH ODS, Thiamin

Cobalamin

Also printed as: cobalamin, cyanocobalamin, methylcobalamin, hydroxocobalamin, adenosylcobalamin, vitamin b12, b12

Found almost entirely in animal foods. Absorption needs intrinsic factor from the stomach, which declines with age.

What the research says Well established

Treating deficiency works and matters, because untreated deficiency causes nerve damage that can become permanent. No established benefit for people with normal levels.

Worth knowing: Vegans, people over 50 and long-term metformin or proton pump inhibitor users are the groups who actually need it. Excess is not known to be harmful.

Source: NIH ODS, Vitamin B12

Riboflavin

Also printed as: riboflavin, riboflavine, vitamin b2, b2, E101

Involved in energy metabolism. It is the reason a B-complex tablet turns urine bright yellow, which is harmless.

What the research says Some human evidence

Corrects deficiency. Higher doses, around 400mg daily, have some trial support for reducing migraine frequency.

Worth knowing: Generally well tolerated.

Source: NIH ODS, Riboflavin

Niacin

Also printed as: niacin, nicotinic acid, niacinamide, nicotinamide, inositol hexanicotinate, vitamin b3, b3

Two forms behave differently. Nicotinic acid causes flushing and affects blood lipids; niacinamide does neither.

What the research says Some human evidence

Corrects deficiency. High-dose nicotinic acid does change cholesterol numbers, but large outcome trials did not find it reduced heart attacks when added to a statin.

• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.
• Causes flushing Harmless but startling: skin reddening and tingling, usually within an hour.

Worth knowing: Doses above about 50mg of nicotinic acid commonly cause flushing. High doses can affect the liver and blood sugar, and should be medically supervised.

Source: NIH ODS, Niacin

Pantothenic acid

Also printed as: pantothenic acid, calcium pantothenate, d-panthenol, dexpanthenol, vitamin b5, b5

Widely present in food, which is where the name comes from: pantothen is Greek for "from everywhere". Deficiency is very rare.

What the research says Some human evidence

Little reason to supplement in people eating a normal diet, and little trial evidence of benefit from doing so.

Worth knowing: Generally well tolerated.

Source: NIH ODS, Pantothenic Acid

Pyridoxine

Also printed as: pyridoxine, pyridoxine hydrochloride, pyridoxine HCl, pyridoxal-5-phosphate, P5P, PLP, vitamin b6, b6

Involved in protein metabolism and in making neurotransmitters.

What the research says Well established

Corrects deficiency. Has reasonable evidence for nausea in pregnancy, where it is used under medical guidance.

• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.

Worth knowing: Sustained high doses cause peripheral neuropathy, which may not fully reverse. EFSA cut its upper limit to 12.5mg a day in 2023, down from 30mg; the US limit remains 100mg. Worth checking B-complex, energy drink and nerve-support labels, which often carry 50mg or more in a single tablet.

Source: EFSA, upper intake level for vitamin B6 (2023)

Ascorbic acid

Also printed as: ascorbic acid, L-ascorbic acid, sodium ascorbate, calcium ascorbate, magnesium ascorbate, ascorbate, E300, vitamin c, asid askorbik

An essential vitamin. The body cannot store much of it, so anything beyond what it needs that day is largely passed in urine.

What the research says Well established

Deficiency causes scurvy, and correcting a deficiency clearly works. For colds, reviews find regular supplementation shortens them slightly on average; starting it once you already feel ill has not reliably helped.

• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.
• Commonly upsets digestion Bloating, wind or loose stools are the usual complaints, especially at first.

Worth knowing: Large doses can cause diarrhoea and stomach upset, and may matter if you have a history of kidney stones.

Source: NIH ODS, Vitamin C

Cholecalciferol

Also printed as: vitamin d3, cholecalciferol, d3, vitamin d2, ergocalciferol, calciferol, vitamin d

Made in skin exposed to sunlight and taken in from food. Stored in the body, which is why excess matters more here than with vitamin C.

What the research says Well established

Supplementing clearly corrects deficiency and supports bone health alongside calcium. Trials of high doses in people who are not deficient have generally not shown the broader benefits once hoped for.

• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.

Worth knowing: Fat-soluble and stored, so sustained high doses can build up. Check with a pharmacist before taking more than 4000 IU daily.

Source: NIH ODS, Vitamin D

Tocopherol

Also printed as: tocopherol, alpha-tocopherol, d-alpha-tocopherol, dl-alpha-tocopherol, tocopheryl acetate, mixed tocopherols, tocotrienol, E307, vitamin e

A family of related compounds. Natural form (d-alpha) is absorbed better than synthetic (dl-alpha), so the same milligram figure is not equivalent between products.

What the research says Some human evidence

Deficiency is rare in people eating normally. Large trials of supplementation in well-nourished people have mostly not found the protective effects expected.

• May increase bleeding Worth knowing before surgery or dental work, and if you take aspirin or a blood thinner.
• Affects blood thinners Can change how warfarin and similar medicines work, in either direction. If you take a blood thinner, do not start or stop this without telling your doctor.
• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.

Worth knowing: High doses can increase bleeding risk, which matters if you take warfarin or other blood thinners, or have surgery coming up.

Source: NIH ODS, Vitamin E

Phylloquinone / menaquinone

Also printed as: vitamin k1, vitamin k2, phylloquinone, phytonadione, menaquinone, MK-7, MK-4, vitamin k

K1 comes mostly from green vegetables, K2 from fermented foods and some animal products. Involved in blood clotting and in how the body handles calcium.

What the research says Some human evidence

Clearly needed for normal clotting. K2 supplements for bone density have promising but still limited trial evidence, mostly at MK-7 doses of 100-200mcg.

• Affects blood thinners Can change how warfarin and similar medicines work, in either direction. If you take a blood thinner, do not start or stop this without telling your doctor.

Worth knowing: Interferes directly with warfarin. If you take warfarin, do not start or stop a vitamin K supplement without telling your doctor.

Source: NIH ODS, Vitamin K

Also printed as: whey protein, whey concentrate, whey isolate, whey hydrolysate, casein, milk protein

A milk protein. Isolate has less lactose than concentrate.

What the research says Well established

Protein supports muscle building alongside training. It is food, and works as food does.

• Dairy derived A milk product, so relevant for milk allergy and lactose intolerance.

Worth knowing: A dairy product, so relevant for milk allergy and lactose intolerance.

Source: General nutrition references

Also printed as: xanthan gum, E415, INS 415

A fermentation-produced thickener.

What the research says Not an active ingredient

Not an active ingredient. Approved.

• Commonly upsets digestion Bloating, wind or loose stools are the usual complaints, especially at first.

Worth knowing: Large amounts can cause wind and loose stools.

Source: EFSA additive assessments

Also printed as: zinc gluconate, zinc picolinate, zinc citrate, zinc sulphate, zinc sulfate, zinc oxide, zinc acetate, zink

Involved in immune function, wound healing and taste. The amount of actual zinc differs from the amount of the compound on the label.

What the research says Well established

Zinc lozenges started within a day of symptoms have modest trial evidence for shortening a cold. Correcting deficiency matters; routine high-dose use in well-nourished people does not have good support.

• Has a real ceiling Unlike most of this aisle, more is genuinely worse here. Check the total across everything you take, since the same nutrient appears in several products.
• Blocks absorption of other things Reduces how much your body takes up of certain minerals and medicines. Space them a couple of hours apart.

Worth knowing: Sustained intake above 40mg daily causes copper deficiency. Can reduce absorption of some antibiotics.

Source: NIH ODS, Zinc