Does L-Arginine Work? may earn compensation through affiliate links in this story.
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L-arginine is an amino acid that your body converts to nitric oxide, which boosts circulation and blood flow by dilating your blood vessels. L-arginine also participates in urea formation, which eliminates ammonia from the body. The amino acid also stimulates the release of hormones, such as insulin and growth hormone. Studies suggest L-arginine therapy may be effective for problems you may have that are related to poor circulation and blocked blood vessels.


L-arginine, which was first isolated in 1886, is usually classified as a nonessential amino acid in adults because your body can make it. Children and adults who are weakened by illness, trauma or infection may not produce sufficient amounts for their needs. In these individuals, L-arginine becomes semi-essential because dietary sources become more important. Dietary sources include protein-containing foods, such as meat, fish, poultry, dairy products, soy, eggs, walnuts and peanuts.

Possible Benefits

Besides showing promise in the treatment of heart, blood vessel and blood pressure conditions, there is data suggesting that taking L-arginine may decrease the risk of respiratory infections, improve poor wound healing and recovery from surgery. There also are indications that the amino acid's ability to stimulate insulin may help decrease diabetic complications. Also, its role in urea formation from ammonia may help treat kidney disease and metabolic acidosis.

Known Efficacy

L-arginine is known to be an effective treatment for deficiencies in growth hormone, for which the FDA has approved its use. Indications include conditions such as panhypopituitarism, gigantism, acromegaly, or pituitary adenoma. L-arginine is usually administered for these conditions in the form of injections. Milder symptoms of deficiency include hair loss, fatty liver, skin rash and constipation. Healthy adults usually do not need L-arginine supplements.


Doses vary widely, depending on the conditions being treated, most of which lack established therapeutic dose ranges. Studies have involved doses ranging from 700 milligrams to 20 grams given from one to four times a day. Individuals who self-treat with L-arginine supplements may combine it with other supplements. L-arginine is available in stores and online in pills and cream. Possible side effects when taken orally include diarrhea, bloating, abdominal pain, gout, low blood pressure and allergies. Check with your physician before including L-arginine in your health regimen.

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