A new investigation has prompted retailers to pull a number of products over health fears
Supplements containing as much as 12.5 times the recommended safe upper limit of popular vitamins and minerals are being sold on online marketplaces, Which? has warned. Which? looked at Vitamin D, Vitamin A, Vitamin B6 and Zinc supplements listed for sale on popular marketplaces including AliExpress, Amazon, eBay, Superdrug, Temu and TikTok Shop.
The NHS recommends a daily intake of Vitamin D is 10 micrograms (µg) each day but adults can safely take up to 100µg, including from food sources. However, Superdrug Marketplace, TikTok shop and eBay all listed the Nuke Nutrition 10,000 IU (250µg) vitamin D3 supplements for sale.
Nuke Nutrition immediately withdrew the product from sale while they investigated. On AliExpress, Which? found two different vitamin D3 supplements in 50,000 IU, or 1,250µg doses – 12.5 times the recommended daily dose.
According to the NHS, a dose as high as 10,000 IU can put users at greater risk of hypercalcaemia – too much calcium in the blood – which can potentially have wide-ranging consequences from vomiting and confusion, to weakening bones and kidney failure. This type of dose might be used to treat a deficiency of vitamin D and taken once a week, for a short period of time – for example six weeks – but should only happen under a doctor’s supervision.
Which? also found Vitamin D supplements for children for sale on these marketplaces which contained far more than the recommended dose of 2,000 IU or 50µg for those aged between one and 10. Temu had “Growth” and “Height Growth Maximiser” supplements from the brand Pslalae available to buy, described as “perfect for kids, teens and adults”, containing 2,500 IU (62.5µg) of vitamin D3.
Vitamin A is crucial for vision, supporting the immune system and maintaining healthy skin. The NHS advises consuming no more than 1500µg of Vitamin A a day, and in 2024 the European Food Safety Authority advised consuming no more than 3000µg, to support vision, the immune system and healthy skin.
Etsy, TikTok shop and eBay all sold 25,000 IU or 7,500µg vitamin A supplements from the brand Mother Nature. Consumers are recommended to consume no more than 10mg of Vitamin B6, but Which? found the supplement at a dose of 100mg on Temu as well as Solgar and Holland & Barrett.
Holland & Barrett withdrew the product from sale after being alerted by Which?. Amazon’s most popular zinc supplement – which the NHS recommends should be taken at no more than 25mg – was from the brand WeightWorld and contained 50mg.
The 50mg Now Foods zinc supplement, also for sale on eBay and TikTok shop, was even labelled as “Amazon’s Choice”. Both Amazon and Superdrug Marketplace also offered a 50mg zinc supplement from the brand New Leaf. The NHS warns that having more than 25mg of zinc a day is more likely to lead to a copper deficiency, which can cause fatigue and anaemia.
Which? head of food policy Sue Davies said: “It’s shocking that supplements containing potentially dangerous doses of popular vitamins and minerals are so readily available online. Taking more than the recommended dose of these vitamins and minerals has been linked to some really harmful side effects such as liver damage and weakened bones.
“Better regulation and oversight of the supplements industry is desperately needed so that consumers are not put at risk by regularly consuming products which contain more than the advised safe upper levels.”
AliExpress said: “The platform has effective prevention and control strategies in place, and we noticed that this non-compliance product had already been taken down by corresponding monitoring rule early this month before receiving this enquiry.”
Amazon said: “We require all products offered in our store to comply with applicable laws and regulations, and the products flagged by Which? meet the current government mandated regulatory guidance in relation to upper levels for vitamins and minerals. However, we are aware there is continued debate around what the right guidance should be and we look forward to continuing to work with industry experts and government agencies in this area.”
Ebay said: “The limits published by the NHS and the Food Standards Agency’s Expert Group on Vitamins and Minerals are advisory levels only. We continue to review our policies in line with evolving guidance from health authorities to help ensure Ebay remains a safe and trusted marketplace.”
Holland & Barrett said: “As a responsible retailer, we regularly carry our detailed reviews led by our science and regulatory teams and we took the proactive decision earlier this year to bring our vitamin B6 range in line with the EFSA advisory limit. As a result, newly reformulated products will be available to customers this month.
“H&B products not in line with the EFSA guidelines are already being withdrawn, with this process due to be complete by end of October 2025.”
Mother Nature said: “Our product is not marketed for long-term daily use, and we actively encourage customers to consult with their doctor before starting high-dose supplementation especially in cases of pregnancy or pre-existing medical conditions.”
The brand said a “cautionary statement” had now been added directly to its product labels. New Leaf said: “Our zinc supplement provides 50mg per serving to offer flexibility in dosage, as many customers prefer to take one tablet (25 mg) rather than the full serving.
“The higher dosage accommodates individuals who choose to consume 40-50 mg daily to help reduce the duration or severity of colds and flu, and to support skin health (acne, eczema, wound healing) as well as athletic performance and recovery, levels comparable to typical ZMA formulations.”
Superdrug said: “Our customers’ health and wellbeing are always our priority. Our marketplace platform sellers must follow the guidance provided and we have therefore removed all the products that have been highlighted by Which?”
Nestle Health Science, on behalf of Solgar, said its supplement levels fell within recommended guidance, adding: “The levels of vitamin B6 found within our products are consistent with other B vitamin supplements found on the UK market.”
Temu said: “Temu complies with all applicable UK laws and regulations governing the sale of food supplements. We expect all sellers to follow local laws and regulations, and listings found to contravene these are subject to prompt review and removal.”
TikTok shop said: “We have removed all of the flagged listings from our platform and we consistently align our policies with regulatory and national guidance, including from the NHS.”