Can arginine and lysine increase growth hormone levels?
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Growth hormone is linked to muscle protein production. Interest in possible athletic benefits from supplementing with individual amino acids was raised after researchers realized that when certain amino acids, such as arginine, are infused directly into the bloodstream of hospital patients suffering from burns, there was a corresponding rise in growth hormone levels in their blood. Some researchers have found that taking arginine and lysine supplements can increase growth hormone levels in healthy young men as well. However other research studies did not show this and some research has suggested that even if arginine does transiently increase growth hormone levels, the raise is not greater than what normally happen in response to resistance exercise. |
So from a practical standpoint arginine would need to be taken several hours before or after exercise. Because it takes several grams of these amino acids to produce a growth hormone response, some participants of the studies complained of intestinal discomfort. Researchers at this time are not really convinced that this happens or would happen in everyone.
Can arginine increase nitric oxide and enhance blood delivery to working muscle?
Nitric oxide (NO) is a powerful vasodilator. It is produced by cells lining blood vessels and arginine is used by the enzyme nitric oxide synthase (NOS) to make nitric oxide. The idea is that arginine supplementation is able to increase NO production and increase blood delivery and thus amino acids and other nutrients to muscle cells during and after exercise. These nutrients could in turn strengthen the processes that build muscle in response to resistance exercise. In addition to the positive benefits of arginine in this manner, researchers have also indicated that citrulline might be beneficial as well being that it can be used to make arginine. One reason is that a lot the arginine that is consumed is metabolized by arginase in the intestinal bacteria and the small intestine wall and liver and never makes it to the blood vessels of muscle. On the other hand, citrulline is not metabolized in such a manner. In addition, polyphenolic compounds in grape extract might serve to optimize NOS activity.
Can ornitine or OKG enhance muscle mass?
Ornithine and its derivative ornithine-α-ketoglutarate (OKG) have received considerable interest from weight-training athletes more son in the past. Ornithine is an amino acid not found in our proteins. However, it does exist independently in our body and is fundamentally involved in the formation of urea. Like arginine, supplemental ornithine was popularized after scientists reported that when ornithine was infused into blood there was a corresponding increase in growth hormone. Some researchers have also reported that oral supplementation of ornithine also increases circulating growth hormone in a respectable percentage of participants. However, the needed dose translates to as much as 170 mg of ornithine per kilogram body weight, which amounts to 14 grams of supplemental ornithine daily for a 180 lb male. Ornithine dosages of this size are usually associated with intestinal discomfort and diarrhea; again, it has not been determined whether the potentially induced increase in growth hormone leads to increased muscle gain. On the other hand, other researchers have not found that OKG raises growth hormone levels, and no one has found increases in muscle mass with supplementation.
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