Amazon weight loss product reviews 'positively misleading' customers, say researchers

'We should be cautious about using reviews like these when deciding about health choices'

Customers aren't deliberately trying to misinform others, but those who had a positive experience were more likely to share their results than those who had a poor experience (Getty)

Customers should approach online reviews of health products with caution, say University of Aberdeen researchers.

An analysis of clinical trial data and user-generated online reviews has shown that customers are prone to exaggerating the effects of weight loss and cholesterol treatments, especially when they have positive results.

The researchers examined more than 1,600 Amazon.com reviews, and found that Benecol reviewers described an average drop in cholesterol over three times above what was found in carefully controlled trials.

Similarly, reviewers of Orlistat, a weight loss pill, claimed to have lost around twice as much weight as participants that took part in clinical trials.

“These treatments are not entirely ineffective,” said the University of Aberdeen’s Dr Micheal de Barra. “However, what we show is that the reputation as described in these reviews is much more positive than the clinical trial data show.”

He stressed that customers weren’t deliberately trying to misinform others.

Rather, users who had a positive experience were more likely to share their results than those who had an average or poor experience, skewing the reviews positively.

“Only some people who try a treatment will then go on to tell other people about their experience. However this subset of people are usually only those who have good outcomes," he added.

“The problem is that people with average or poor outcomes don’t tend to share their experiences. This means you get a positively skewed view of the treatment.

“We should be cautious about using reviews like these when deciding about health choices. These narratives have a powerful influence on our own future health behaviour because they provide simple and clear anecdotes, but this study shows that they can be very misleading.”