Supplements A–Z
One page per supplement: which form to choose, the dose that matters, what the label may legally claim in the UK and EU, the NHS and EFSA upper limits, and the products whose labels we have checked.
Unsure what NRV, elemental magnesium or "claims on hold" mean? See the glossary →
By goal
Start from what you want to improve.
Sleep Melatonin, magnesium, ashwagandha, valerian and other sleep supplements ranked by evidence, with UK and EU rules, doses, limits and label-checked products. Gut & digestion Psyllium, probiotics, lactase and other digestion supplements ranked by evidence, with authorised claims, doses, red flags and checked products. Immune support Vitamin D, zinc, vitamin C, probiotics and echinacea ranked by evidence, with the UK and EU immune claims, safe doses and the products we have checked.
Vitamins
Vitamin D Vitamin D3 compared: NHS advice and daily dose in µg and IU, UK and EU limits, D3 vs D2, whether you need K2 and label-checked products. Vitamin B12 Vitamin B12 compared: why labels show 1,000 µg, cyanocobalamin vs methylcobalamin, who needs it (vegans, over-50s), NHS advice and products. Biotin Biotin compared: why products give 100 times the reference intake, what helps hair, the NHS 0.9 mg figure, lab test interference and how to choose. Multivitamins Multivitamins compared by %NRV: when iron, vitamin D, B6, vitamin A and beta-carotene matter, NHS advice, what the evidence says and how to choose. Vitamin C Vitamin C compared: ascorbic acid, buffered, Ester-C or liposomal, why 1,000 mg is more than you absorb, NHS limits, colds evidence and checked products.
Minerals
Magnesium Magnesium compared by form and dose: elemental magnesium per daily dose, NHS and EFSA supplement limits, authorised claims and label-checked products. Zinc Zinc compared: bisglycinate, picolinate, citrate or gluconate, the NHS 25 mg limit vs German advice, colds evidence, claims and checked products. Iron Iron compared: test first, ferrous salts vs bisglycinate, alternate-day dosing, NHS and EU limits, authorised claims and label-checked products.
Omega-3 & CoQ10
Omega-3 Omega-3 compared by mg of EPA + DHA per daily dose: fish, krill or algae oil, TG vs ethyl ester, authorised claims, safe limits and label-checked products. Coenzyme Q10 CoQ10 compared: ubiquinone or ubiquinol, typical doses, what the evidence shows for statins, heart and blood pressure, interactions and authorised claims.
Sports nutrition
Skin & joints
Collagen Collagen compared by grams per daily dose: peptides, marine, type II, what the evidence shows for skin and joints, claims and label-checked products. Hyaluronic acid Oral hyaluronic acid compared: alone or with collagen, what the 2025 meta-analysis found for skin, authorised claims, molecular weight and how to choose. Joints Glucosamine, chondroitin, MSM and collagen for joints compared: trial doses, what the evidence and NICE say, claims, interactions and how to choose.
Plants & botanicals
Turmeric & curcumin Turmeric compared by curcuminoids per daily dose: piperine and high-absorption forms, safety limits, liver warnings and what the label may say. Ashwagandha Ashwagandha compared: root vs leaf extracts (KSM-66, Sensoril), trial doses, legal status in the UK and EU, who should avoid it and label-checked products.