Last week, TA from New York sent me a question about a supplement designed to boost growth hormone (GH) levels.
“Have you heard about a growth hormone stimulator named SeroVital?” she wrote. “Is it any good or the usual hype?”
According to the website, SeroVital is “an affordable oral formula that encourages the pituitary gland to increase growth hormone production at a more youthful rate, naturally, without dangerous drugs or synthetic hormone injections.”
What sort of results can you expect from injectable GH? And do growth hormone stimulators like SeroVital deliver the same benefits at a fraction of the cost?
In 1990, a huge amount of excitement was generated from research published in the New England Journal of Medicine describing the dramatic effects of growth hormone treatment in a small group of men.
The men (aged between 61 and 81) were treated with injections of human growth hormone three times a week for six months. The injections were sufficient to increase the men’s growth hormone levels to those of a normal person aged 20 to 40 years.
The volunteers gained around 10 pounds of lean body mass, and lost almost eight pounds of fat. Bone mineral density also increased. Growth hormone treatment also produced thicker, less wrinkled, younger-looking skin. In fact, skin thickness was restored to a level typically seen in a 50-year-old.
Even younger men and women appear to benefit. In one study, growth hormone led to a 12% decrease in body fat and a 4% increase in lean mass in a group of exercising men and women aged 22 to 33 years.
GH injections have also been shown to increase collagen (connective tissue) synthesis in muscle and tendon. This ties in with the experience of some athletes, who report that GH seems to help their injuries heal more quickly.
As I mentioned earlier, some trials also show an increase in skin thickness, which might explain why the guy I was speaking to at the gym the other day told me that using GH got rid of some of the lines on his face.
All of this talk about GH increasing lean mass might sound very exciting. But it’s only half the story.
Firstly, an increase in lean body mass doesn’t automatically mean more muscle.
In one study, a group of 16 men (aged 21-34) was assigned to a strength training + GH group or a strength training + placebo group. While GH injections led to an increase in fat-free mass, they had no effect on musclemass. To quote the researchers directly:
Fat-free mass (FFM) and total body water increased in both groups but more in the GH recipients. In the young men studied, resistance exercise with or without GH resulted in similar increments in muscle size, strength, and muscle protein synthesis, indicating that 1) the larger increase in FFM with GH treatment was probably due to an increase in lean tissue other than skeletal muscle and 2) resistance training supplemented with GH did not further enhance muscle anabolism and function.”