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Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "

11.05.2010

Study shows effect of six months on testosterone enanthate and growth hormone

In 2002 the results of a trial were published in JAMA, which brought an end to doctors' dreams of maintaining vitality in the elderly through testosterone and growth hormone therapy. 'Growth hormones are not yet ready for mass use', concluded first author Marc Blackman of the National Institutes of Health at the time. On a sunny Saturday afternoon we re-read Blackman's study. See for yourself whether you agree with him.

Blackman gave hormones to 130 healthy American men and women aged between 65 and 88. In this article we concentrate on the men and leave the women out. The men got substances that are more interesting for athletes and bodybuilders than the hormones given to the women.

The men in the placebo group got nothing. A second group of men got a 100 mg injection of testosterone twice a week. The researchers used Delatestryl, produced by Bio-Technology General. A third group of men injected themselves three times a week with Genentech's growth hormone preparation Nutropin. The starting dose was 30 mcg/kg bodyweight. The men's average weight was 72 kg, so they got 7.4 IE/day.

Life extenders use up to 4 IE per day. There are stories in the world of chemical sport of athletes who inject 24 IE growth hormone per day, but more usual schemes indicate 8 IE per day. The researchers reduced the dose halfway through the trial to 20 mcg/kg/injection because too many test subjects were suffering from side effects.

The men did no training.

Let's start with the small successes the researchers report. The test subjects' body composition improved. The group that used testosterone and growth hormone showed most improvement. This group lost 4 kg fat and gained 4 kg muscle mass.

The researchers assessed the men's muscle strength by measuring their maximal power for six exercises: bench-press, upright-row, biceps-curl, triceps-extension, leg-press and leg-curl. The table below shows the effect on body strength in kg. The effect is disappointing if you look at the changes in body composition. That's not so strange: in many trials where subjects are given steroids but don't train, performance hardly improves.

The same is the case for maximal oxygen uptake. VO2 max improves as a result of the hormones, especially for the growth hormonen/testosterone combination, but the effect is disappointing.

And then we come to the side effects. Growth hormone, testosterone and growth hormone plus testosterone users report oedema, gynecomastia and arthralgia [joint pain]. A bigger problem is carpal tunnel syndrome [pain, numbness and loss of strength in your hands through restriction of the nerve channels]. One third of testosterone plus growth hormone users suffer from this.

The effect that the researchers are most concerned about is shown below. Insulin resistance increases as a result of growth hormone use. Some men even became diabetic during the experiment.

"Our findings suggest that growth hormone and sex steroid supplementation in a selected group of healthy aged women and men can exert potentially beneficial effects on body composition, and possibly improve muscle strength and cardiovascular endurance capacity in men", the researchers conclude. "The beneficial effects of growth hormone appeared to be augmented by coadministration of testosterone."

Nevertheless, the researchers warn against the elderly taking growth hormone. "However, at this time, growth hormone interventions in elderly individuals should be confined to controlled research studies."

Source:
JAMA. 2002 Nov 13; 288(18): 2282-92.