Potentially dangerous diet pills sold on eBay, Wish and AliExpress, Which? finds

A Which? investigation has found dozens of weight loss supplements containing potentially dangerous ingredients being sold on eBay, Wish and AliExpress, as the consumer champion continues to call for online marketplaces to be given greater legal responsibility for the safety of products sold on their sites.

Which? uncovered listings for the substances despite their potential side-effects including increased blood pressure and heart rate. High doses of the drugs could lead to strokes, heart attacks and kidney damage. 

Often marketed to body-conscious people as weight loss supplements and workout enhancers, the two substances – yohimbine and synephrine – are ingredients that the Medicines and Healthcare products Regulatory Agency (MHRA) has said have “considerable potential to cause harm if used without medical supervision or advice.”

However despite these warnings and the fact that yohimbine and synephrine are not meant to be routinely available for sale without medical supervision, Which? was able to purchase and have delivered a sample of three items each from eBay, Wish and AliExpress respectively. Each online marketplace had at least a dozen products listed on their websites that contained yohimbine or synephrine at the time of Which?’s investigation.

Of the nine products Which? purchased, two carried no health warnings or dosage information at all. One had the name of the ingredient – in this case yohimbine – clearly visible on the outer packaging, though it still made its way into the UK and to the address of the recipient. 

In response to Which?’s investigation, eBay and AliExpress said they had removed the product listings found by Which?. Wish said it was in the process of removing them, though at the time of writing yohimbine and synephrine products were still available on the site.

Sites have told Which? they will take down listings when they are reported, but it does not appear as though measures to prevent listings appearing in the first place are working, or that the marketplaces are adequately monitoring for those listings to take them down – relying on Which? and others to spot them and report them instead.

Prices on the supplements varied considerably. Some items were priced from as little as £2.39 plus postage, though some capsules were priced at more than £80.

They were available to be shipped from countries including India, the USA, Ukraine and Poland, with many offering free postage.

Discussing the effects of yohimbine and synephrine generally, toxicology expert Dr James Coulson, a member of the UK’s Committee on Toxicology, told Which? that common symptoms could include agitation, aggression, nausea, and increased heart rate and blood pressure. He said: “When it comes to these drugs the critical effects we are concerned about is their effect on the sympathetic nervous system and particularly their effect on blood pressure” and “if you’d taken a lot of it you’d then start to see the effects of secondary organ damage.”

Which? also submitted a Freedom of Information request to the MHRA’s Yellow Card scheme, which tracks reports of adverse drug reactions from healthcare professionals and members of the public. The MHRA confirmed that, in the last decade, it had received six reports of “suspected adverse drug reactions” to yohimbine, and two reports of “suspected adverse drug reactions” to synephrine. 

In its response the MHRA said that a report of a reaction “does not necessarily mean that it has been caused by the drug in question” but it also flagged that not every suspected adverse reaction is flagged via the scheme.

Both supplements are popular among some bodybuilders and gym goers but there have been a number of studies that have warned of potential side effects, while some consumers have reported unverified concerns about them on social media and forums.

On one forum, one person claimed to have taken up to 300mg of yohimbine before a workout and said the side effects were so concerning they considered going to hospital. The person said they experienced excessive sweating and “sky high” pulse and blood pressure. One of the yohimbe products Which? purchased recommended a dose of two 300mg capsules per day.

The consumer champion’s latest investigation once again raises serious concerns over the lack of checks and monitoring carried out by online marketplaces and highlights the need for them to have legal responsibility for unsafe products on their sites. 

Currently responsibility sits with the third-party sellers on these sites but there does not appear to be adequate enforcement action taken to stop potentially unsafe supplements and medicines being sold to UK consumers. This could leave people worryingly exposed to products that can cause harm.

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

“It is concerning that our investigation has revealed these slimming supplements containing potentially dangerous ingredients are readily available on online marketplaces. The limited regulation of these sites is not working – and that’s leaving people exposed to substances that can be harmful. 

“Online marketplaces must be given greater legal responsibility for the safety of products sold on their sites, so that shoppers are far better protected.

“Regulators also need to be more proactive in policing potentially dangerous products that are offered for sale on these sites, which are becoming increasingly popular places to shop.”

Notes to editors

  • Which? found dozens of items containing yohimbine and synephrine on eBay, AliExpress and Wish between June and August 2021.

What are Yohimbine and Synephrine?

Both yohimbine and synephrine are substances that are extracted from certain herbs. They are used as ingredients in weight loss pills and pre workout supplements.

Yohimbine is derived from the bark of a tree found in parts of Africa and is traditionally used as a male aphrodisiac, as well as being marketed as a weight loss supplement. Synephrine is a pharmacologically active substance derived from bitter orange extract. 

Yohimbine is banned for sale in the UK, except when sold by a pharmacist. However, Which? understands it is not routinely available on prescription. https://www.gov.uk/government/publications/list-of-banned-or-restricted-herbal-ingredients-for-medicinal-use/banned-and-restricted-herbal-ingredients

Regulation of synephrine is more complicated than that of yohimbine. The MHRA assesses individual products containing the ingredient on a case by case basis. 

Because it can cause physiological effects, synephrine would also normally be regarded as a prescription-only medicine, according to the MHRA, making it subject to strict quality, safety and efficacy controls.

These ingredients are not always restricted in other countries. 

Are yohimbine and synephrine dangerous?

Both substances can cause serious harm, Dr James Coulson, a toxicology expert, told Which?. Asked if they can be dangerous, he said: “The answer is yes, to both.”

Coulson, who is a Reader at Cardiff university and a practicing consultant physician at the Cardiff and Vale NHS Trust, is a member of the UK’s Committee on Toxicology and a consultant to the UK National Poisons Information Service. 

He has treated patients who have had complications arising from taking yohimbine, and has dealt with reports of complications arising from synephrine use via the National Poisons Information Service.

Common symptoms of having taken either yohimbine or synephrine can include agitation, aggression, nausea, and increased heart rate and blood pressure, Coulson said. 

But taken in high doses there can be more “dramatic presentations [of symptoms],” that can damage the heart and kidneys, sometimes permanently, and can lead to stroke and heart attack.

“When it comes to these drugs the critical effects we are concerned about is their effect on the sympathetic nervous system and particularly their effect on blood pressure,” he said.

“If you’d taken a lot of it you’d then start to see the effects of secondary organ damage because of the rise in blood pressure [and] you’d expect to see potentially damage to the cardiovascular system. A lot of this will depend on individual susceptibility. If you’ve got underlying cardiac disease it can certainly be manifested in one of these episodes.”

One other concern among healthcare professionals is that people who take diet supplements often take more than one ingredient at the same time, unknowingly increasing their risk of experiencing worrying side effects. 

One reason for this is the perception that, if something is herbal, it is therefore harmless. “Some of the most effective poisons we have occur naturally,” Coulson said. “The ecosystem has been trying to kill us for years.

Rights of reply


an eBay spokesperson:

“We take the safety of our users extremely seriously and work closely with authorities like the Medicines and Healthcare Products Regulatory Agency (MHRA) to help ensure sellers and listings on eBay comply with laws and regulations.

“These items are banned from eBay’s platform and have been removed. eBay sellers must comply with the law. eBay sellers are prohibited from listing prescription drugs, in line with rules set by MHRA.

“In addition to our own prevention teams and technology, eBay works closely with the MHRA and other regulators across the globe who directly report and remove listings of concern. Sometimes opportunistic sellers attempt to circumvent our filters, but when they do our policy teams remove the listings quickly.”


A Wish spokesperson:

“Per our Merchant Policies and Terms of Service, we generally restrict the sale of products that require a prescription or a medical professional’s supervision. The sale of vitamins and supplements is limited to a finite number of pre-approved merchants within specific regions. Each of those merchants are required to provide relevant safety certifications and legitimate proof of authorization.

“The listings highlighted by Which? are being removed from our platform, and we will continue to investigate ways in which we can actively prevent such products from re-listing.”


An AliExpress spokesperson said:

“AliExpress takes very seriously the safety of all our customers and we work hard to ensure a safe shopping environment. The items identified by Which? as part of its investigation have been removed from the AliExpress platform. Sellers who have these products listed will be penalized according to our policies.”

Medicines and Healthcare products Regulatory Agency (MHRA)

An MHRA spokesperson said:

“Yohimbine and Synephrine are substances that are extracted from certain herbs. Each is capable of causing significant physiological effects, especially to blood pressure and heart rate. They have considerable potential to cause harm if used without medical supervision or advice.

“It is highly likely that finished products containing either yohimbe or synephrine would satisfy the definition of a medicinal product and we have previously determined many such products to be medicines.

“However, as we are required to take a case-by-case approach when classifying products taking into account all available product information, it would not be appropriate to state that all products containing yohimbe or synephrine would automatically be medicines.

“If a product is determined to be a medicine, it cannot be legally sold or supplied in the UK. The Marketing Authorisation provides a guarantee that the medicine has met set standards of quality, safety and efficacy in the UK and the MHRA will have records of what the medicine contains.

“MHRA takes public health seriously. There are robust regulatory requirements on medicines – including their manufacture, distribution, retail sale/supply and advertisement. Breaches of the legal requirements are investigated and appropriate action taken.

“MHRA has developed an excellent relationship with eBay and other platforms and we have arrangements in place to request the withdrawal of unauthorised medicines.

“As a result of the information provided, our Borderline team will review and make determinations of the products being offered. Where we find products deemed as medicines and not holding an appropriate authorisation, we take action.”

About Which?

Which? is the UK’s consumer champion, here to make life simpler, fairer and safer for everyone. Our research gets to the heart of consumer issues, our advice is impartial, and our rigorous product tests lead to expert recommendations. We’re the independent consumer voice that influences politicians and lawmakers, investigates, holds businesses to account and makes change happen. As an organisation we’re not for profit and all for making consumers more powerful.

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