Growth hormone-releasing products have been around for a long time, but the truth is they don't work quite as well as advertisers claim. Let me give you some background information, so you will have a better understanding of your body's growth hormone (GH) response and be able to make an educated choice about whether to try these supplements.
GH is a peptide hormone (many amino acids linked together). It's secreted by the anterior pituitary gland in pulsatile patterns throughout the day, but especially after intense exercise and during sleep. It is responsible for the growth and maintenance of almost all tissues in the body. Interestingly, GH lasts only a few minutes in the bloodstream. Upon release, it's rapidly taken up by the liver and metabolized into insulin like growth factor (IGF).
Growth hormone and growth factors haven't been studied with the same rigor and thoroughness as other hormones. Science has only begun to unravel the mystery of GH, including conditions that may alter its release.
• Arginine The intravenous infusion of the amino arginine produces a relatively consistent increase in GH secretion in normal healthy subjects. Arginine is therefore used by endocrinologists to test individuals for proper pituitary function.
If a patient is suspected of having a problem secreting GH, his or her doctor performs an amino acid infusion test. The doctor injects an arginine solution directly into the patient's circulatory system. The physician then takes blood samples at different time intervals to measure whether the pituitary is functioning normally.
This medical test has been the basis for claims made by marketers of GH-releasing supplements. Taking an intravenous infusion of amino acids, though, is a world away from taking these substances orally. It has never been consistently demonstrated that oral administration of arginine produces a similar rise in GH, or even that a small increase in GH would mediate an anabolic response in skeletal muscle.
One investigation conducted by researchers in Italy (A. Isidori et al., "A study of growth hormone release in man after oral administration of amino acids," Current Medical Research and Opinion, 7:475-81, 1981) may have set the stage for future research in this area. Arginine pyroglutamate (L-arginine2-pyrrolidone-5-carboxylate) was combined with L-lysine hydrochloride and given orally in doses of 1.5 grams (g) of each amino. Fifteen males between the ages of 15 and 20 were given the aminos, and then tested for increases in biologically active GH. Results showed elevations in GH approximately two to eight times above baseline values 30-90 minutes after the subjects swallowed the compound. Plasma insulin levels also increased. While this sounds promising, remember that the rise in GH was short-lived and relatively small compared to amounts athletes would require to produce increases in muscle mass.
• Ornithine The other amino acid used in these products is ornithine, which is very potent in stimulating GH release via intravenous infusion. Interestingly, it also appears to be effective when given orally. In one study using bodybuilders as subjects, Luke Bucci, PHD, examined various oral doses of ornithine and resultant GH release (L. Bucci et at., "Ornithine ingestion and growth hormone release in bodybuilders," Nutrition Research, 10:239, 1990). Doses up to 12 g were used, and they produced varying effects on GH. Only the 12-g dose, however, caused a significant, albeit transitory, rise in GH. Still, that increase, while statistically significant, isn't remotely comparable to the increase produced by an actual GH injection. In fact, the increase in GH observed in this study was less than that typically occurring in normal subjects during sleep. One more thought: High doses of ornithine administered orally can also cause stomach cramping and diarrhea.
Increasing GH levels might be tempting. Supplementing with ornithine does not appear to be a good choice to achieve higher levels, though, considering the amount of ornithine needed (12 g or more) to do so, and the possible side effects of stomach discomfort and bowel problems. If your stomach is upset and you get diarrhea, you're more than likely to miss meals and/or not absorb nutrients efficiently. Not getting enough food will surely limit your gains, even if you do increase your GH secretion.
Based on available research, the doses of this amino marketed to bodybuilders (two to three grams per day) would have no effect on GH levels and hence would not augment muscle mass or strength.
It's also important to understand a little about protein breakdown and absorption in your body. Studies have demonstrated that single amino acids are not absorbed well by the gastrointestinal tract; instead, the body seems to prefer dipeptides and tripeptides (two and three amino acids linked together). Thus, as far as uptake by the body goes, oral administration of single amino acids, like arginine and ornithine, appears to be inefficient.
Don't waste your hard-earned money on these types of over-the-counter secretagogues or "GH releasers." There are several other kinds of GH releasers on the market now that are pretty interesting.
For now, you would be better off spending your money on a good whey protein powder, glutamine and a qualitycreatine supplement, as well as filling your refrigerator with nutritious muscle-building foods like steak, chicken breasts, fish, eggs, oatmeal, rice and fresh vegetables. The real way to grow is not by taking GH enhancers, but by engaging in a solid training/nutrition program and getting plenty of rest.