The medication has been found on Amazon, eBay and Superdrug despite is being illegal to sell in the UK.
Multiple online marketplaces have been found to be illegally selling a prescription-only drug.(Image: Getty Images)
Consumer watchdog Which? has uncovered multiple online marketplaces selling medication illegally in the UK despite it being prescription-only. This could be putting a variety of Brits’ health at risk as they are freely able to buy the banned products.
The drug in question is melatonin, which is a hormone that helps regulate sleep and treat certain sleep issues such as insomnia. While this drug is available over the counter in some countries like the US, it is only given on a prescription basis in the UK.
Melatonin naturally occurs in your body, with your levels rising at night before returning to normal during the day. This helps control how and when you sleep. However, if you have probelms with sleeping you can take a synthetic version of melatonin which will add to your bodies natural supply and help your fall asleep quicker and for longer.
According to the Medicines and Healthcare products Regulatory Agency (MHRA), this difference is due to the drug being a risk to patient safety. They explained: “Melatonin is considered to pose an identifiable risk to public/patient safety due to its ability to exert significant modification to human physiology.”
However, Which? has discovered multiple melatonin supplements, patches and more being advertised between October 2025 and January 2026. This includes retailers such as Amazon, Etsy, eBay, Superdrug Marketplace, Temu and AliExpress.
Even more worrying is that some of these advertised products claim to contain higher doses than the maximum dose prescribed by the NHS. The healthcare service states that the usual dose is 2mg but this can go up to a maximum of 10mg for longer-term sleep problems.
Melatonin is prescribed to help patients who struggle with sleep issues such as insomnia.(Image: Getty Images)
Professor Azeem Majeed, head of primary care and public health at the Imperial College London, added: “Melatonin has a direct effect on the sleep–wake cycle and broader physiological processes, and its use can lead to side effects such as headaches, dizziness and mood changes. It can also interact with a number of commonly used medicines.
“Medical oversight helps ensure that it is used appropriately, that underlying sleep problems (that are often better addressed through non-drug approaches) are not overlooked, and that its use in vulnerable groups – such as children or during pregnancy – is carefully managed.”
However, despite regulation being in place to protect users, some suppliers have slipped through the cracks and have advertised their own products. Most of the melatonin products found were in capsule, tablet, or gummy form.
Many of the medicines were also claimed to be “100 per cent drug free”, despite the fact that melatonin is classed as a medicinal drug in the UK.
The watchdog in the past few months also found many products being advertised at the maximum dose of 10mg, while one product from the brand Balincer on Temu was as high as 30mg.
Professor Majeed warned: “30mg daily is well above the recommended dose and could lead to an increased risk of side effects including drowsiness, headaches, low blood pressure, dizziness and disruption to the hormonal system.”
With the drugs being shipped from within the UK and abroad, some instances even saw melatonin not being mentioned in the image or product name. Instead it was only mentioned in the list of ingredients, so many shoppers wouldn’t have even known what they were buying.
While melatonin can be bought over the counter in other countries, it is only given through a prescription in the UK.(Image: James Leynse/Getty Images)
Some of the marketplaces responsible for selling melatonin and other misleading products have responded to the investigation conducted by Which?
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 also added: “Safety is our top priority, and we require all products offered in our store to comply with applicable laws, regulations and Amazon policies.
“We take action to maintain a safe selection for our customers, including removing non compliant products, and outreach to sellers, manufacturers, and government agencies for additional information, when appropriate. The highlighted items have been removed.”
Superdrug, who sold melatonin patches, argued: “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 has also since guaranteed: “Temu prohibits the sale of products containing melatonin and removes any such listings once detected, with penalties applied to sellers for violations.”