The science of rHGH and its implications on the bodybuilder
Hello everyone, this is going to be an informational post on rHGH, we will be taking a look at several studies and perhaps shedding light on all of the information (or misinformation) out there currently.
My educational background: I have a bachelors of science in Kinesiology. I am now studying to become a clinical lab scientist.
1) Effects of GH supplementation on muscle.
There are several studies that show there is a positive correlation between GH and myofibrillar protein synthesis (that is protein synthesis in muscle cells). However these studies were done primarily on growth hormone deficient (GHD) children and adults, and studies of GHD animals as well animals not fully grown. All of these studies have shown that GH supplementation has a significant effect on muscle growth, strength and performance.
Some early studies looking at GH administration on local myofibrillar synthesis in health adult subjects had relatively few subjects and have been challenged by large placebo-controlled studies examining the effect of long term GH treatment.
One of these larger studies looked at 47 healthy elderly men and women, who received either placebo or rhGH for a 12 week period, the study showed no difference in muscle strength, muscle power and muscle hypertrophy.
The other large study looked at exercising young men, and found no effect of GH on muscle protein turn over, or muscle mass.
***So these may seem like discouraging results for the use of GH for the purposes of bodybuilding, but its not the end of the story.
2)Effect of GH on collagen synthesis in connective tissue
Studies performed in vitro (meaning in a controlled laboratory medium; test tube) has shown that IGF-1 plays a VERY important role in promoting collagen synthesis on the cellular level. IGF-1 in a dose-dependent relationship causes increase of DNA synthesis, which can not be accomplished with just mechanical loading (exercise).
In vivo studies (studies performed on a living organism) have supported the in-vitro findings. Studies of GH deficient dwarf rats showed a significant increase in collagen turn-over in knee tendon and ligaments following only 14 days of rhGH supplementation.
On humans, the exact same results have been replicated. In a large placebo-controlled study, rhGH administration increased whole-body soft-tissue collagen synthesis dose-dependently.
More-over, in a study of healthy active males, comparing the effect of exercise and rhGH supplementation vs exercise and placebo; it was shown that a significantly higher collagen synthesis was reported in rhGH supplementation group, compared to exercise and placebo.
***This is a profound finding because it shows that exercise isn't necessary for GH to cause an increase in collagen synthesis, although it is plausible that exercise acts synergistically. The importance of all of this collagen synthesis is that it will lead to tendons and muscle that are structurally stronger and less prone to injury.
Conclusions: Tendons and especially the myotendinous junction (connection point between muscle cells and collagen fibers) are often considered a "weak link in the chain" which is concerning for the bodybuilder with fast growing muscles (using AAS with heavy strength training). Thus the advantages of hGH are an indirect one for the bodybuilder. The athlete is able to train at a higher intensity and/or reduce necessary recovery time between exercise sessions, without running the risk of getting injured. There is also evidence showing that Anabolic steroids can have a weakening effect on tendons, but that is a topic for another time.
Anectodal reports of hGH increasing muscle size are not supported in the medical literature. It may very well be that GH causes fluid retention rather than actual increase in contractile protein concentration, thus creating an impression of a bigger muscle. Although more studies need to be done to look at intra-muscular myofibrillar protein synthesis to confirm this.
Thank you for reading.
References:
1. http://press.endocrine.org/doi/abs/10.1210/jcem.76.2.8432773
2. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2821728/
3. http://www.ncbi.nlm.nih.gov/pubmed/24235105
4. http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0838.2005.00455.x/abst...
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Ya, ive found that gh is pretty much worthless for muscle growth, it doesnt cause hyperplasia, theyve only found that to occur in animals but never humans. It does have a place though, the look it gives ones physique, the fat burning (its not that dramatic but its there) the collagen synthesis like you said, and when you combine it with some other compounds it does before a very powerful muscle builder. But without them it does nothing. If muscle gain is the goal then its better to just use the money for it on higher quality gear. Maybe when you reach a certain point in physique developement im talking freak status it can help push you further, but for most of us its the cost to benefit analysis for muscle growth is shitty. I like it for its other benefits though.
There are interesting studies showing the use of different types of anabolic steroids on tendon injury. Some studies have shown that high testosterone levels reduce collagen synthesis. While other studies have shown that anabolic steroids increase collagen synthesis, but the collagen being synthesized is primarily collagen type III versus collagen type I (Collagen type III being much weaker)
Overall there isn't enough evidence in the literature to draw any conclusions at this point about the use of anabolic steroids and tendon injuries.
It could be that the large gains in strength in the muscle are out pacing the tensile properties of the tendon.
But if you have the money, running HGH in your cycle makes sense to prevent injuries from occurring.