Dozens of weight loss supplements sold on eBay and Wish contain 'dangerous' stimulants that can lead to strokes and heart attacks, UK watchdog warns

Dozens of weight loss supplements with potentially dangerous ingredients are being sold on popular websites, an investigation has found.

The products contain yohimbine and synephrine that are said to have ‘considerable potential to cause harm if used without medical supervision or advice’. 

Experts at the consumer group Which? were able to buy nine potentially harmful products from eBay, Wish and AliExpress. 

They were among dozens of listings for products with the suspect ingredients. Prices varied considerably with some costing as little as £2.39 and others more than £80.

The suppliers were based in countries including India, the United States, Ukraine and Poland.

Drugs containing the ingredients are only supposed to be available in the UK through a prescription. 

Yohimbine and synephrine are popular among bodybuilders and gym enthusiasts, because they are thought to be powerful fat burners that suppress hunger. 

The Medicine & Healthcare Regulatory Agency said products containing the two substances, which are extracted from certain herbs, are likely to be considered medicines and, as a result, it would be illegal to sell and supply them.

The websites removed the products from sale after they were alerted by Which?.

Yohimbine is derived from the bark of a tree found in parts of Africa, while, synephrine is a substance derived from bitter orange extract. Both drugs block adrenergic receptors that are found in fat cells. It is thought this process increases metabolism and reduces hunger

eBay, Wish and AliExpress each sold dozens of diet pills containing 'potentially dangerous' ingredients called yohimbine and synephrine that can increase heart rate and blood pressure. Pictured: the diet pills bough from the sites by Which?

Dr James Coulson, a member of the UK Committee on Toxicology, said said: ‘The critical effects we are concerned about is their effect on the sympathetic nervous system and particularly their effect on blood pressure. If you’d taken a lot of it you’d then start to see the effects of secondary organ damage.’

Sue Davies of Which? 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 ned to be more proactive in policing potentially dangerous products.’ 

An eBay spokesman insisted it took the safety of users ‘extremely seriously’. Wish said it would work to prevent such products from re-listing. AliExpress said it would penalise the sellers.

What are yohimbine and synephrine?

Both yohimbe and synephrine are extracted from herbs.

Yohimbine is derived from the bark of a tree found in parts of Africa.

It can act as a sexual stimulant, so was traditionally used to treat erectile dysfunction. 

But it is also touted as a weight loss pill.

Meanwhile, synephrine is a substance derived from bitter orange extract. 

Both drugs block adrenergic receptors that are found in fat cells.

It is thought this process increases metabolism and reduces hunger.

But studies have reported mixed results on its effectiveness, with scientist spotting flaws in the methodology of studies that say the drugs works. 

In the UK, products containing the drugs are only available on prescription and are not allowed to be sold, supplied or advertised as retail products.

The Medicines and Healthcare products Regulatory Agency, the UK's medicines regulator, warned the substances have 'considerable potential to cause harm if used without medical supervision or advice'.

Which? bought three products from eBay, Wish and AliExpress that contained yohimbine and synephrine and spotted dozens more.

Two of the products did not include any health warnings on their packaging and had no information on the dose included in each pill.

And one product clearly named yohimbine on the packaging, but Which? was still able to buy it in the UK.

Which? did not name the weight loss supplements sold online that contain the drugs, but said eBay and AliExpress removed the items once it was informed about them.

But Wish is still in the process of removing them, so they are still available on its website, Which? said. 

The MHRA said it had received six reports of suspected adverse reactions to yohimbine and two reports of reactions to synephrine in the last 10 years.

The cases were reported through its Yellow Card scheme, which tracks reactions to medicines. 

Yohimbine and synephrine are 'often marketed to body-conscious people as weight loss supplements and workout enhancers', Which? said. 

But the MHRA said the drugs have 'considerable potential to cause harm if used without medical supervision or advice'. 

Dr James Coulson, a member of the UK's Committee on Toxicology, scientific advisers to the Government, said common side effects from taking the weight loss pills include agitation, aggression, nausea and an increased heart rate and blood pressure. 

He told Which?: '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.

'If you'd taken a lot of it you'd then start to see the effects of secondary organ damage.'

Sue Davies, Which? head of consumer protection policy, said it is 'concerning' that the supplements are 'readily available' on online marketplaces.

This signals the 'limited regulation' of these websites is 'not working' and is 'leaving people exposed to substances that can be harmful', she said.

She added: '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.'

A spokesperson for the MHRA 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.'