There are two sources of arginine; arginine in the food chain and free-form arginine from supplements. Food-source arginine is found in abundance in turkey, chicken, and other meats. Non-food-source arginine is called L-arginine and is created through a fermentation process which separates arginine from all other proteins. In the presence of food and other amino acids, L-arginine will act like food-source arginine but when L-arginine is separated from its nutrient boundaries by the removal of all other amino acids, then L-arginine undertakes a different role, becoming capable of crossing the blood-brain barrier and stimulating growth hormone release secreted by the anterior pituitary.
Growth hormone serum levels peak during adolescence and begin to drop after age 23. Aging reduces natural growth hormone production, which results in added body fat, reduced muscle tissue, slowed healing, lack of elasticity in the skin, and reduced immune function.
Human pituitary growth hormone secretion is evidenced in human males, females, and children following intravenous administration of 30 grams of arginine (in 30 minutes) in adults and 0.5 grams/kilogram of bodyweight in children. Female response is somewhat higher than male response. Oral administration of L-arginine also results in the release of Human Growth Hormone. Oral ingestion of another amino acid, Ornithine, results in growth hormone release, but since arginine turns into ornithine, and ornithine does not replace arginine for growth, arginine is the superior growth hormone releasing agent.
Additionally, arginine has very low toxicity. Doses of 0.5 grams per kilogram up to 30 grams total given within 20 to 30 minutes has caused no untoward reactions and is considered safe. Patients diagnosed with renal or hepatic insufficiency and those with insulin-dependent diabetes should avoid large doses of arginine, or be medically monitored. Normal persons can tolerate 30 to 60 grams per day arginine. While food-source arginine is necessary for growth in children, free-form L-arginine is not recommended for anyone under the age of 23.
The body’s demand for dietary arginine is increased by physical trauma (of any type). Dietary supplementation of arginine:
- Increases collagen; the protein providing the main support for bone, cartilage, tendons, connective tissue, and skin.
- Increases wound breaking strength.
- Improves the rate of wound healing.
- Inhibits cellular replication of tumors.
- Increases sperm count and motility by over 100%.
- Detoxifies ammonia (The urea cycle is the metabolic detoxification process utilized by the body to eliminate toxic ammonia in which ammonia is turned into urea and excreted in the urine).
- Minimizes thymic involution that occurs with injury.
- Decreases nitrogen losses after trauma.
The demand for arginine in humans and animals occurs in response to:
- Physical trauma,
- Dorsal skin wounds,
- Physical pain registered by the skin,
- Blood transfusions (pinprick reactions as well as foreign substance reaction),
- Tumor burden and malignancies,
- Dental procedures (pinprick reaction, pain, and blood loss),
- Muscle and bone growth spurts.
Tumor suppression is evidenced in the presence of L-arginine. In the Barbul study, tumors recurred in 100% of the control animals. But in the arginine-supplemented group, only about 60% of the tumors recurred and the animals with tumors survived longer
Supplementation of arginine in the diet inhibits development and increase in size of cancerous tumors, both chemically induced and naturally occurring.
Insulin can block growth hormone release, so high serum insulin levels are counterproductive to GH release. Insulin itself is capable of stimulating muscle growth, but it also strongly stimulates fat storage. Muscle growth stimulation from insulin is minuscule compared to muscle growth stimulated by growth hormone.
Adults who choose to take L-arginine supplements for growth hormone release should observe the following guidelines. The product:
- Should not be in capsule form – you cannot fit enough L-arginine in capsules to elicit a GH response.
- Should not contain Lysine. L-arginine and Lysine should not be taken together as Lysine is a direct antagonist of arginine. L-arginine taken near food can interfere with Lysine metabolization thus causing potential reactivation of an already existing herpes virus.
- Should not contain competing proteins or amino acids.
- Should not contain insulin stimulating (high glycemic) ingredients.
- Should contain the correct synergists.
- Should include explicit directions in regard to timing and contraindications (ie diabetics)