Growth hormone does not improve physical performance

Anyone who injects growth hormone with the intention of gaining muscle mass and improving performance should think again.

The hormone improves neither muscle mass nor physical performance. This is shown in a new dissertation from the Sahlgrenska Academy at Göteborg University in Sweden.

Doping in sport using growth hormone has become more frequent since the middle of the 1980s. The substance does not cause the same aggressive behaviour as anabolic steroids cause, but it can cause problems that include damage to the heart and blood vessels.

“Many of those who abuse anabolic steroids regard growth hormone as the Rolls Royce of doping agents: it is significantly more expensive to use than anabolic steroids. There is, however, no scientific evidence that it increases performance when used alone as a doping agent”, says Dr. Christer Ehrnborg.

Christer Ehrnborg has studied 30 well-trained people living in Göteborg. Twenty of these injected large doses of growth hormone each day for a month, while the other 10 believed that they also were receiving growth hormone but received injections of harmless saline solution instead. Tests of the participants’ physical performance on an exercise cycle showed that the participants receiving growth hormone did not perform better than those receiving saline solution.

“It has been a matter of controversy whether growth hormone actually causes an effect or whether it is a matter involving mass psychology. Both our study and studies carried out by others suggest that taking growth hormone will not make you a better athlete”, says Christer Ehrnborg.

Measurement of the body compositions of the participants showed that injecting growth hormone reduced the fraction of body fat and increased the amount of water in the body.

“Athletes who inject growth hormone immediately notice an effect in the body, and they assume that the change must improve their performance. We cannot see, however, any effect of increased muscle mass from the hormone in our experiments”, says Christer Ehrnborg.

Doping with growth hormone is difficult to prove, since natural levels can vary widely from one person to another, and from one occasion to another in the same person. Christer Ehrnborg presents results in a second article in which elite athletes were studied for a full year in order to determine which factors affect the natural variation in growth hormone levels.

“We found several interesting biomarkers that can be used when analysing blood samples. A new doping test is in the process of being launched, based partially on our research results. The method must first be validated to show that it can be used in judicial proceedings”, says Christer Ehrnborg.