Illegal melatonin supplements widely advertised on popular online marketplaces and health retailers, Which? warns

Which? has found melatonin being illegally marketed on popular online marketplaces - including AliExpress, Amazon, eBay, Superdrug and others - some at excessively high doses, as the consumer champion calls on the government to regulate the supplements industry more effectively. 

Melatonin, a hormone that plays a role in regulating sleep, is only available with a prescription in the UK. 

However, Which? saw scores of supplements being illegally advertised on AliExpress, Amazon, eBay, Etsy, Superdrug Marketplace, and Temu between October 2025 and January 2026.

According to the NHS, the usual starting dose of melatonin doctors would prescribe is 2mg but Which? consistently saw 10mg listed - the maximum dose usually recommended by the NHS for people suffering with long-term insomnia. 

The consumer champion even saw one supplement - Balincer's Melat Onin Nighttime Sleep Aid - advertised for sale on Temu, which claimed to contain 30mg of melatonin. That is 15 times the usual starting dose prescribed in the UK. 

Worryingly, in many of the listings Which? found, melatonin was not mentioned in the image or product name but was only visible on the list of ingredients.

For example, the consumer champion saw eight supplements claiming to be ‘night time fat burners' on eBay that listed melatonin among their ingredients. One example, 'Live Nature's Night Time Fat Burner' supplements did not specify how much melatonin was in the product at all.

Sellers also hid that products contained melatonin in their listings to stop the platforms detecting and removing the products. 

For example, several products listed on Temu used spaces to get around automatic detection by naming the product ‘melat onin' or only listing it as an ingredient. Eight ‘melat onin' products were advertised on Temu in November, but all had been removed by January. While it is good to see action being taken to remove these products, they should never have been listed for sale in the first place.

Sellers seem to be constantly finding new ways to avoid detection. Which? found several supplements marketed on eBay and Temu that hid melatonin from the product listing, instead only mentioning it in the less prominent product description. 

For example, the ‘Sleep 10mg' capsules from the brand Xemenry did not mention melatonin in the listing but in the description, it said ‘our melatonin helps you fall asleep faster'. The product actively listed 10mg of ‘sleep' in the list of ingredients. Making up ingredients in a food supplement is against the law and, since it is not possible to portion out 10mg of sleep and put it in a supplement, that is exactly what these brands are doing.

Which? also saw listings for melatonin skin patches and teas, which seemed to avoid detection by online platforms and health retailers. For example, Snooze sleep patches from the Friendly Patch Co (7mg melatonin) - which the brand itself does not sell in the UK because of UK's melatonin regulations - were available on Amazon, Etsy, and Superdrug Marketplace through third-party sellers. 

The consumer champion also found a third-party seller which had been advertising Celestial Seasoning melatonin tea - which the brand itself does not sell in the UK - on Amazon since November 2024. Amazon took it down when Which? shared the listing with them.

It is illegal to market melatonin without a prescription in the UK. This is because without proper medical supervision, it can interfere with common medications like anti-depressants and contraception and cause unpleasant side effects like headaches, dizziness and mood changes.

Even more worryingly, if shoppers choose to buy melatonin from illegal sellers, there is no knowing what they will end up with as the sellers are operating outside legal channels. Products could contain too much melatonin - or none at all - alongside a host of other ingredients and fillers, which could have unpleasant side effects. 

This is especially risky for vulnerable groups like children, who should not be given melatonin without medical supervision and certainly not unknown products bought from online marketplaces. 

Over the last six months, Which? has repeatedly found examples of misleading and unsafe supplements being listed on some online marketplaces and popular health retailers. In these instances, it is difficult for consumers to distinguish between sleep supplements and illegal medicines when shopping online as it is not always clear up front exactly what products contain. 

Better oversight of the supplement industry is desperately needed to make sure unsafe and illegal products are taken off the market. The government must ensure there is strong enforcement in place so that any companies breaking the rules know they will be held to account. 

Sue Davies, Which? Head of Consumer Policy, said: 

“It's really worrying that melatonin is being illegally marketed on popular online marketplaces without a prescription - putting consumers' health at risk. 

“If shoppers buy from sellers illegally advertising melatonin, there is no telling what the products will contain - they could contain too much melatonin or other potentially harmful substances, which could lead to dangerous side effects. 

“Better oversight of the industry is desperately needed so the government and regulators can crack down on illegal listings and ensure that any sellers who break the rules are held to account.”

-ENDS- 

Notes to editors

About the research

In October 2025 - January 2026, Which? looked at online product listings of melatonin supplements across a range of online marketplaces. 

Right of replies

AliExpress said: “AliExpress takes product safety very seriously and maintains strict policies to ensure a safe and compliant online shopping experience. Among these policies is a clear prohibition on the cross-border sale of medications and dietary supplements through our platform. All third-party sellers on AliExpress are required to comply with applicable laws and adhere to our platform rules. 

“We have promptly removed the flagged listings flagged by Which?. We are also taking appropriate enforcement actions against the sellers found to be in violation of our policies.”

Amazon said: “Safety is our top priority, and we require all products offered in our store to comply with applicable laws, regulations and Amazon policies.

“We develop innovative tools to prevent unsafe products from being listed and if we discover a product was undetected by our automated checks, we address the issue immediately and refine our controls.

“We take action to maintain a safe selection for our customers, including removing noncompliant products, and outreach to sellers, manufacturers, and government agencies for additional information, when appropriate.

“The highlighted items have been removed.”

eBay said: “Consumer safety is a top priority for eBay. These items violate eBay policy and have been removed. We work diligently to prevent and remove unsafe product listings through seller compliance audits, block filter algorithms, AI-supported monitoring by in-house specialists, and close partnerships with regulators. Together, these measures help to prevent millions of potentially unsafe items from being listed each year.

“We are reviewing the wider marketplace to remove any identical listings. We are continually updating filters to prevent bad actors from circumventing our policies. Notably, a number of the listings highlighted by Which? were unavailable for purchase even prior to the investigation being shared with eBay.”

Superdrug said: “Topically applied products that contain melatonin as one of their ingredients are widely available for general sale across the UK. 

“We have contacted the Medicines and Healthcare products Regulatory Agency (MHRA) for clarification on the guidelines for including melatonin as an ingredient within topically-applied products.”

Temu said: “Thank you for bringing this to our attention. Temu prohibits the sale of products containing melatonin and removes any such listings once detected, with penalties applied to sellers for violations.

“Our monitoring systems continuously screen the platform for non-compliant products. As you noted, many of the melatonin products you identified had already been detected and removed before your inquiry. The remaining products were removed on the same day you flagged them, and the sellers penalized.

“Bad actors will attempt to circumvent controls by deliberately misspelling ingredients or mislabelling products to evade text and image recognition. We have invested heavily in compliance systems combining proprietary technology with expert human review to identify these bad actors and ban them from our platform.

“We welcome reports of potential non-compliant listings so we can take prompt action.”

Balincer, Etsy, Live Nature and Xemenry did not respond to Which?'s requests for comment.