Supplements containing as much as 12.5 times the recommended safe upper limit of popular vitamins and minerals sold on online marketplaces, Which?

[Sly Saint]

Which? is calling for better regulation and oversight of supplements after the consumer champion found products containing potentially dangerous doses of popular vitamins and minerals for sale on online marketplaces.

Between September and October 2025, Which? looked at Vitamin D, Vitamin A, Vitamin B6 and Zinc supplements listed for sale on popular online marketplaces including AliExpress, Amazon, eBay, Superdrug, Temu and TikTok Shop to see whether they contained safe amounts of vitamins and minerals.

The vitamins and minerals were selected using recommendations for safe upper limits set by UK experts based on an assessment of the risk.

Worryingly, the consumer champion found supplements on sale containing as much as 12.5 times the safe upper limit for these popular vitamins and minerals - and in some cases without the warning statements that the supplements industry agreed with the government to provide.

Vitamin D

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.

Superdrug Marketplace, TikTok shop, and eBay all listed the Nuke Nutrition 10,000 IU (250µg) vitamin D3 supplements for sale - more than double the safe upper limit. When Which? contacted Nuke Nutrition about this product, they immediately withdrew it 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 safe upper limit.

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 this should only happen under a doctor’s supervision.

Even more concerningly, Which? found Vitamin D supplements for children for sale on these marketplaces which contained far more than the recommended dose. For children aged 1-10 the maximum dose of vitamin D recommended by the NHS is 2,000 IU or 50µg.

Temu had ‘Growth’ and ‘Height Growth Maximiser’ supplements from the brand Pslalae available to buy, described as ‘perfect for kids, teens and adults’. But, these vitamins contained 2,500 IU (62.5µg) of vitamin D3.

Vitamin A

Vitamin A is crucial for vision, supporting the immune system and maintaining healthy skin. The NHS advises consuming no more than 1500µg a day and in 2024, the European Food Safety Authority advised consuming no more than 3000µg. According to the NHS and Expert Group on Vitamins and Minerals (EVM), excessive amounts of vitamin A can increase weakness of bones and the risk of fracture, as well as damage the liver.

Vitamin B6

According to the NHS and EVM, Vitamin B6 helps the body use and store energy and to form haemoglobin, the substance in red blood cells that carries oxygen around the body. It's recommended to consume no more than 10mg.
Which? found a Vitamin B6 supplement at a dose of 100mg for sale at Temu as well as well-known health retailers Solgar and Holland & Barrett. Holland & Barrett withdrew the product from sale after being alerted by Which?.

According to the NHS, a dose of this size taken over time can increase the risk of suffering permanent peripheral neuropathy

Zinc

Zinc helps with making new cells and enzymes and wound healing but the NHS recommends taking no more than 25mg. If a product has more than 25mg, the voluntary guidance says that it should have a statement that long term usage can lead to anaemia. 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.

Some of the supplements found in Which?’s investigation did not have nutrition information detailing how much of the active ingredient is actually in the supplement - making it nearly impossible for consumers to know how much they are taking.

Supplements containing as much as 12.5 times the recommended safe upper limit of popular vitamins and minerals sold on online marketplaces, Which? warns - Which?

www.which.co.uk

eta: articles on the report in various publications

MSN

 

[RedFox]

High doses of vitamin D make more sense than the others, because your body stores it for a while. You can take a large dose weekly instead of a small dose daily. 10,000 IU a day is the lowest dose ever found to give someone a problem, but it's quite a reasonable dose if taken weekly.

 

[shak8]

On supplements that have much more than 3x the minimum daily recommended of a vitamin or mineral:

There are dangers to heed, imho.

On a personal level: my relative developed debilitating peripheral neuropathy after taking a melatonin product for months that had a huge amount of B6 in it. Could have been a co-incidence but likely not.

If she had asked her doctor beforehand....she might have avoided this hit to her quality of life.

The supplement industry relies of the public's (or their own) mistaken notion that more must be better.

(The poison is the dose someone dear said to me recently.)

 

[Creekside]

Are the active molecules cheaper than the filler? Seems silly for companies to overspend on inputs.

 

[hotblack]

The lesson seems to be, don’t buy anything like this from any online marketplaces. Regulations in the UK and EU are generally quite good for medicines, food, etc. but we seem to let some companies ignore them.

 

[rvallee]

I will never understand the resistance to regulating supplements. Sometimes it's almost said like it's something to be proud of, because supplements have little to no medical value for the most part, so it would be demeaning to bother. Except people do take them anyway, and in some cases they do have medical value.

Hell, cheese is far more regulated than supplements. As are been and wine. Humans are so freaking weird all the damn time.

 

[hotblack]

Humans are so freaking weird all the damn time.

I may get this printed on a badge or t-shirt