Overview:
L-arginine is a chemical building block called "an amino acid." It is obtained from the diet and is necessary for the body to make proteins. L-arginine is found in red meat, poultry, fish, and dairy products. It can also be made in a laboratory and used as medicine.
L-arginine is used for heart and blood vessel conditions including congestive heart failure (CHF), chest pain, high blood pressure, and coronary artery disease. L-arginine is also used for recurrent pain in the legs due to blocked arteries (intermittent claudication), decreased mental capacity in the elderly (senile dementia), erectile dysfunction (ED), and male infertility.
Some people use L-arginine for preventing the common cold, improving kidney function after a kidney transplant, high blood pressure during pregnancy (pre-eclampsia), improving athletic performance, boosting the immune system, and preventing inflammation of the digestive tract in premature infants.
L-arginine is used in combination with a number of over-the-counter and prescription medications for various conditions. For example, L-arginine is used along with ibuprofen for migraine headaches; with conventional chemotherapy drugs for treating breast cancer; with other amino acids for treating weight loss in people with AIDS; and with fish oil and other supplements for reducing infections, improving wound healing, and shortening recovery time after surgery.
Some people apply L-arginine to the skin to speed wound healing and for increasing blood flow to cold hands and feet, especially in people with diabetes. It is also used as a cream for sexual problems in both men and women.
How does it work?
L-arginine is converted in the body into a chemical called nitric oxide. Nitric oxide causes blood vessels to open wider for improved blood flow. L-arginine also stimulates the release of growth hormone, insulin, and other substances in the body.
L-arginine is POSSIBLY SAFE for most people when taken appropriately by mouth, administered as a shot, or applied to the skin, short-term. It can cause some side effects such as abdominal pain, bloating, diarrhea, gout, blood abnormalities, allergies, airway inflammation, worsening of asthma, and low blood pressure.
Special Precautions & Warnings:
Pregnancy and breast-feeding: L-arginine is POSSIBLY SAFE when taken by mouth appropriately for a short-term during pregnancy. Not enough is known about using L-arginine long-term in pregnancy or during breast-feeding. Stay on the safe side and avoid use.
Side effects:
Children: L-arginine is POSSIBLY SAFE when used by mouth in premature infants in appropriate doses. However, L-arginine is POSSIBLY UNSAFE when used in high doses. Doses that are too high can cause serious side effects including death in children.
Allergies or asthma: L-arginine can cause an allergic response or make swelling in the airways worse. If you are prone to allergies or asthma and decide to take L-arginine, use it with caution.
Cirrhosis: L-arginine should be used with caution in people with cirrhosis.
Guanidinoacetate methyltransferase deficiency: People with this inherited condition are unable to convert arginine and other similar chemicals into creatine. To prevent complications associated with this condition, these people should should not take arginine.
Herpes: There is a concern that L-arginine might make herpes worse. There is some evidence that L-arginine is needed for the herpes virus to multiply.
Low blood pressure: L-arginine might lower blood pressure. This could be a problem if you already have low blood pressure.
Recent heart attack: There is a concern that L-arginine might increase the risk of death after a heart attack, especially in older people. If you have had a heart attack recently, don't take L-arginine.
Kidney disease: L-arginine has caused high potassium levels when used by people with kidney disease. In some cases, this has resulted in a potentially life-threatening irregular heartbeat.
Surgery: L-arginine might affect blood pressure. There is a concern that it might interfere with blood pressure control during and after surgery. Stop taking L-arginine at least 2 weeks before a scheduled surgery.
Possibly Effective for:
Chest pain (angina). Taking L-arginine seems to decrease symptoms and improve exercise tolerance and quality of life in people with angina. However, L-arginine does not seem to improve the disease itself.
Erectile dysfunction (ED). Taking 5 grams of L-arginine by mouth daily seems to improve sexual function in men with ED. Taking lower doses might not be effective. However, there is some early evidence that adding 40 mg of Pycnogenol three times daily might improve the effectiveness of low-dose L-arginine for ED.
High blood pressure. There is early evidence that taking L-arginine by mouth can reduce blood pressure in healthy people, people with high blood pressure, and people with slightly high blood pressure with or without diabetes.
Inflammation of the digestive tract in premature infants. Adding L-arginine to formula seems to prevent inflammation of the digestive tract in premature infants.
Nitrate tolerance. Taking 700 mg of L-arginine four times daily seems to prevent nitrate tolerance in people taking nitroglycerin for chest pain (angina pectoris).
Leg pain associated with poor blood flow (peripheral arterial disease). Research suggests that taking L-arginine by mouth or intravenously (by IV) for up to 8 weeks increases blood flow in people with peripheral arterial disease. However, long-term use (up to 6 months) does not improve walking speed or distance in people with peripheral arterial disease.
Improving recovery after surgery. Taking L-arginine with ribonucleic acid (RNA) and eicosapentaenoic acid (EPA) before surgery or afterwards seems to help reduce the recovery time, reduce the number of infections, and improve wound healing after surgery.
High blood pressure during pregnancy (pre-eclampsia). Although there are inconsistent results about the effects of L-arginine on pre-eclampsia, most research suggests that it can reduce blood pressure in women with this condition.