Testosterone was recently found to be effective for fat loss in young men even in small doses. One recent study showed that men given only 100 milligrams per week of testosterone enanthate lost an average of six percent of their bodyfat after eight weeks.(6) 100 mg per week is generally considered a very low dose by bodybuilding standards. Most impressive about this study was that the result was obtained in young, normal healthy men (aged 18 to 45), not obese or testosterone deficient. Most of the studies showing positive effects with hormone replacement therapy are on subjects who are obese or hormone deficient – i.e. the very subjects most likely to respond. While the amount of muscle gain reported in this study was not reported (it is still just in abstract form), another study showed 100 mg per week of testosterone enanthate was not anabolic.(7) It appears that testosterone has a strong mechanism for fat loss other than increased metabolic rate from increased muscle. Considering how much cheaper testosterone is than growth hormone, it may well be the cost-effective choice for burning fat even if it is slightly less effective overall.
Safety of Growth Hormone and Testosterone
Testosterone is widely believed to be far more dangerous than growth hormone. However, recent research is rapidly showing that much of these dangers have been exaggerated. For instance, the hypothesis that testosterone causes prostate cancer has never been established. In fact, one study even showed a slight negative correlation between testosterone levels and prostate cancer! A study on young men given supraphysiologic doses of testosterone showed no change is prostate specific antigen (PSA), which is one measure of prostate cancer risk.(Cool
Growth hormone may also be less dangerous to the prostate than previously believed. One study showed strong positive correlation with prostate cancer and IGF-1 levels.(9) Since growth hormone stimulates IGF-1 synthesis in the liver, this study and others bring up the possibility of a link of growth hormone and prostate and breast cancer. Keep in mind that statistical correlations do not necessarily prove causality, i.e. IGF-1 has not yet been proven to be a cancer-causing villain. Actually IGF-11 may be one of the culprits in the cancer story, and not IGF-1. At the Serano sponsored Symposia on the Endocrinology of Aging in October, 1999 and at the Endocrine Society Meeting in June, 1999 there was an informal consensus that patients on growth hormone did not increase their risk of breast or prostate cancer. Several other recent studies have also cast doubt on the role of growth hormone as a cancer-causing villain.
Testosterone may have also gotten a bad rap for its effects on blood lipids. Since testosterone and other anabolic steroids have been shown in some studies to lower HDL cholesterol levels, it was believed that testosterone may increase the risk for heart disease. This was refuted in one recent study on testosterone that showed some positive results. A study on 21 hypogonadal men (aged 36 to 57) showed a replacement dose of testosterone using the Androderm transdermal patch to reduce blood clotting.(9) While HDL levels did drop slightly, blood coagulability is believed to be the more important marker of heart disease risk. Another study showed a very strong negative correlation with testosterone levels and heart disease.
Growth hormone has shown mixed results on its effects on heart disease risk. One study on elderly men and women (aged 65-8Cool showed that growth hormone administration to lower LDL levels, but raised triglyceride levels.(10) Since high LDL and triglyceride levels are considered measures of heart disease risk, growth hormone’s effects on heart disease risk are ambiguous. However, long-term use of growth hormone as been shown to decrease the thickness of the carotid artery lining – i.e. increased room for blood flow.
While much more research needs to be done, I am convinced right now that testosterone replacement therapy in hypogonadal men may be safer than excessively large doses of growth hormone. The long-term studies have not yet been done to test the true long-term effects of these hormones, but the research seems quite clear at the moment. Michael Mooney has reported similar results on safety and side effects of these hormones:
While none of the studies on testosterone or anabolic steroids used for HIV have documented any significant health problems associated with their proper therapeutic use, Dr. Gabe Torres' data on his patients who experienced a reduction in symptoms of HIV-related lipodystrophy with Serostim growth hormone showed that at the standard 5 and 6 mg doses, 80 percent of his HIV patients experienced significant side effects, that included elevated glucose, elevated pancreatic enzymes, or carpal tunnel syndrome. (1)
Conclusion
Don’t get me wrong – I still use both growth hormone and testosterone as part of overall anti-aging programs in my patients. This article is not meant to say one hormone is "good" and another is "bad". It is just my opinion at the moment that the overall benefit/cost ratio for improving body composition is higher with testosterone than growth hormone. By cost, I mean both the monetary price – testosterone is far cheaper than growth hormone, and the side effect/safety profile – testosterone is safer than high-dose growth hormone use.
Since growth hormone is extremely expensive and perhaps riskier than testosterone, I screen patients very carefully and only recommend it to those who either have very low IGF-1 levels and fail growth hormone stimulation tests, or those who have failed to respond to testosterone or other therapies. The new research has also made me confident in encouraging more and more patients to go on testosterone. However, we must keep constant track of the new research to better refine both anti-aging and bodybuilding programs. The science of hormone supplementation is still in its infancy, and there is still a lot more questions that need to be answered.
References
1. Mooney, Michael, HIV Study Shows No Muscle Growth From Serostim Growth Hormone, Medibolics, July, 1999
2. Yarasheski KE; Campbell JA; Smith K; Rennie MJ; Holloszy JO; Bier DM. Am J Physiol Effect of growth hormone and resistance exercise on muscle growth in young men. Am J Physiol, 262(3 Pt 1):E261-7 1992 Mar
3. Crist DM, et al. Body composition response to exogenous GH during training in highly conditioned adults. J Appl Physiol. 1988 Aug;65(2):579-84.
4. Blackman, MR, et al. Effects of growth hormone and/or sex steroid administration on body composition in healthy elderly women and men, Presented at 1999 Endrocrine Society conference, San Diego, California
5. Tagliaferri M, et al. Metabolic effects of biosynthetic growth hormone treatment in severely energy-restricted obese women. Int J Obes Relat Metab Disord. 1998 Sep;22(9):836-41.
6. Anawalt, BD, et al. Testosterone administration to normal men decreases truncal and total body fat . Presented at 1999 Endrocrine Society conference, San Diego, California
7. Friedl KE, et al. Comparison of the effects of high dose testosterone and 19-nortestosterone to a replacement dose of testosterone on strength and body composition in normal men. J Steroid Biochem Mol Biol. 1991;40(4-6):607-12
8. Cooper, C.S., MacIndoe, J.H., Perry, P.J., Yates, W.R. and Williams, R.D.: The effect of exogenous testosterone on total and free prostate specific antigen levels in healthy young men. J Urol, 156:438, 1996.
9. Wallace, J., et. al (1998) Growth Hormone and IGF Res (abstract) 8(4): 329, 348
10. Christmas, C. et al, Effects of growth hormone and/or sex steroid administration on serum lipid profiles in healthy elderly women and men, Presented at 1999 Endrocrine Society conference, San Diego, California
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