Growth hormones in athletes does not increase their performance, according to a new research at the Stanford University School of Medicine.

The researchers summarized the gathered data from 44 previous articles on the effect of growth hormones on athletic performance.

The study revealed that HGH does change body mass but does not gain strength in biceps and quadriceps.

Lead investigator Hau Liu, M.D. said that growth hormone as an athletic enhancer is not easy to detect despite the current controversy on professional athletes such as Andy Pettitte and others.

But in young and healthy volunteers, "we felt that the risks outweigh the benefits," he said. Further work is to be done to measure the impact on athletes, he added.

The study will be published in the March 17 online issue of the Annals of Internal Medicine.