Doctors suggest that teenagers who use muscle-building supplements should be referred to a psychologist to check if they have an eating disorder.

Teenagers who admit to using muscle-building supplements should be referred to a psychologist to check whether they have an eating disorder, according to new guidance for GPs.

Mental health experts have urged GPs to be wary of young adults consuming protein or creatine powders to boost their workouts and quickly build muscle mass.

They fear the habit could be an early sign of body dysmorphia, a disorder that causes sufferers to feel distressed by perceived flaws in their appearance.

This mental health problem, which usually begins in early adolescence, can lead to anorexia and even suicidal thoughts.

Powders such as whey protein and creatine monohydrate have become increasingly popular as dietary supplements for those looking to improve their athletic performance and strength.

They are mixed into smoothies after workouts to help build and repair tired muscles.

The guidelines, published by researchers at the University of Toronto, advise physicians to refer adolescent patients who report using supplements for a full psychological evaluation.

Eating disorder expert and researcher Kyle T. Ganson says primary care physicians should ask patients about the supplements they use and why they are motivated to use them.

Psychologists have also warned that extreme dietary habits associated with muscle building could be causing physical harm to young men.

Excessive protein consumption can damage organs, including the kidneys and intestines.

By looking at the possibility that a fitness obsession could turn into an eating disorder, Ganson says, GPs can better understand their patients’ motivations and educate them about the risks of their behavior.

“The goal is to provide strategies to reduce the negative effects… although we recognize that abstinence (from sex) may not be a realistic goal for all clients,” she added.