Low-self esteem, poor body image and a perception of not meeting the modern ideal of masculinity are driving more men to consume over-the-counter body-building supplements, constituting what researchers believe is an emerging eating disorder.
Supplements such as whey protein, creatine and L-cartinine are used to improve athletic performance and physique and are sold in grocery stores, vitamin shops and online.
The products are popular among gym members to increase energy and build lean tissue mass. But researchers at Alliant International University in Los Angeles said overuse is increasing and dangerous.
"Men are using the supplements in a way that is risky both to their physical health and their health in terms of relationships and their own emotional wellbeing," said Richard Achiro, of the California School of Professional Psychology at the university. "It is an expression, or variance, of eating disorder behaviour in these men."
Unlike anorexia or bulimia in women, which result from a desire to be thin, men are aspiring for a physique that is both lean and muscular, and are using supplements to achieve it.
Achiro said overuse of the products, which are not regulated by the US Food and Drug Administration, can cause diarrhoea, kidney disease and renal failure.
"Taken together low self-esteem and gender role conflict, which is an underlying sense of insecurity about one's masculinity, contribute more to the overuse of these products than body dissatisfaction alone," he explained.
Achiro, who presented his research at the American Psychological Association convention in Toronto on Thursday, found in a study of nearly 200 men who took supplements in the past month that 29 per cent expressed concern about using them.
Eight per cent admitted their doctors told them to cut back or stop and 40 per cent said their use had increased over time.
Achiro said he and his co-author, Peter Theodore, showed statistically that the excessive use of the supplements was a form of eating disorder.
"The way in which men's bodies are being objectified by the media is catching up rapidly to what has been done to women's bodies for decades," he said.
"It makes sense to believe that as that occurs men's mental health and emotional issues are going to be expressed more and more in eating disorder behaviour."