Scientists have warned of the dangers of purchasing weight loss or workout supplements over the internet, amid increasing evidence such products are at risk of contamination from harmful and or illegal substances.

A group of researchers led by Dr Ornella Corazza from the University of Hertfordshire have found that more than 40 per cent of exercise enthusiasts buy supplements or performance and image enhancing drugs (PIEDs) online, with 43 per cent trusting internet blogs and forums for advice on what to buy.

The researchers say the online purchases are strongly linked to a high level of concern for body image, with 83 per cent of those surveyed claiming to care a lot about their physical appearances. This chimes with recent reports of gym goers suffering from ‘bigorexia’ – an anxiety disorder which can cause people to go to dangerous lengths to make themselves bigger and more muscular.

The most common products purchased to lose weight and achieve fitness goals are proteins (58 per cent) and herbal products (34 per cent) such as teas and infusions. More alarmingly, there are also notable numbers using amphetamines (17 per cent), thyroid hormones (17 per cent) and diuretics (15 per cent) bought online.

The researchers found that 28 per cent of the 433 exercise enthusiasts surveyed have experienced side-effects after buying such products online, with reports of skin problems, change in mood, headache, diarrhoea, digestion problems, fast heart rate, irritability and sweating. Meanwhile, another recent study found that men who take muscle-building pills and powders are more likely to develop testicular cancer.

Although the investigation is still in its preliminary stage, the initial findings have been presented to MPs. The authors make the point that it is important not to conflate protein powders with drugs such as amphetamines under a blanket term, but say they hope to raise awareness of the dangers of purchasing products online.

“It is important to note, that we do not think of supplements, PIEDs and new psychoactive substances (NPS) as one in the same,” Roisin Mooney, a researcher working on the project told Health Club Management.

“We don’t doubt that when used correctly supplements may be of use. However, there is an increased amount of evidence that they might be contaminated with undisclosed/harmful substances such as NPS, especially when sold online.”

The research is part of a wider project to provide original data on the availability, motivations, and possible risks associated with the diffusion of PIEDs in society. To view more about the project, click here.