Prescription-only sleep supplement melatonin is being sold illegally on social media and online marketplaces, warns consumer watchdog

A popular sleep medicine has been widely advertised online despite being illegal to buy without a prescription in the UK, according to a Which? investigation.

Melatonin is a hormone that occurs naturally in the body. At night, melatonin levels rise before returning to normal during the day. 

People with sleep problems such as insomnia can take a synthetic version of melatonin for short periods to help them fall asleep. It may also help with symptoms of jet lag. 

In the UK, melatonin is classified as a medicine and not a dietary supplement, meaning it requires a prescription from a doctor.

However, Which? found the medication being advertised on online marketplaces such as AliExpress, Amazon, eBay, Etsy, Superdrug Marketplace and Temu between October 2025 and January 2026.

Melatonin is mainly used to treat short-term sleep problems in people aged 55 and over. It can also sometimes be prescribed by specialists to help with longer-term sleep problems in some children and adults.

It comes as standard tablets, slow-release tablets, capsules and a liquid drink.  

In other countries, such as Spain, France, Italy, Greece, Germany and the US, melatonin is available over the counter.

According to the NHS, the usual dose is one 2mg tablet taken one to two hours before bedtime. 

But according to Which?, they consistently saw 10mg listed, which is the maximum dose usually recommended by the NHS for people suffering from long-term insomnia.

Which? found one supplement – ‘Balincer’s Melat Onin Nighttime Sleep Aid’ – advertised for sale on Temu, which claimed to contain 30mg of melatonin, which is 15 times the usual starting dose prescribed in the UK.

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

The consumer group also found eight supplements claiming to be ‘night time fat burners’ on eBay which 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.

Which? claims that some sellers disguised the fact that products contained melatonin in their listings to stop the platforms from detecting and removing the products.

For example, multiple listings on Temu sed 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. 

The consumer group 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. 

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, which contain 7mg melatonin, are not sold by the brand in the UK because of the tight regulations.

However, Which? claims that the patches 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 reportedly 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.

If shoppers choose to buy melatonin from illegal sellers, there is no way of 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.

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.’

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 penalised.

‘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.