Overview
L-arginine is an amino acid naturally found in red meat, poultry, fish, and dairy. It is necessary for making proteins and is commonly used for circulation.
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. It can be made in a lab and used in supplements.
People use L-arginine for chest pain and various blow flow issues, erectile dysfunction, high blood pressure during pregnancy, and a serious disease in premature infants called necrotizing enterocolitis (NEC). It’s also used for many other conditions, but there is no good scientific evidence to support these other uses.
Uses
Effective for:
Chest pain (angina). Taking L-arginine by mouth seems to decrease symptoms and improve exercise tolerance and quality of life in people with angina. But it doesn’t seem to help widen blood vessels that are narrowed in angina.
Erectile dysfunction (ED). Taking 2.5-5 grams of L-arginine by mouth daily seems to improve sexual function in people with ED. Taking L-arginine with medications such as sildenafil and tadalafil might work better than taking either L-arginine or the medication alone.
High blood pressure. 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.
A serious intestinal disease in premature infants (necrotizing enterocolitis or NEC). Adding L-arginine to formula seems to reduce the risk for this condition in premature infants.
Narrowing of blood vessels that causes poor blood flow to the limbs (peripheral arterial disease). Taking L-arginine by mouth or by IV for up to 8 weeks increases blood flow in people with this condition. But using it for up to 6 months does not help to improve walking speed or distance. IV products can only be given by a healthcare provider.
A pregnancy complication marked by high blood pressure and protein in the urine (pre-eclampsia). Taking L-arginine by IV can reduce blood pressure in pregnant people with pre-eclampsia. L-arginine might also reduce the risk of pre-eclampsia in people who are at high risk for this condition. IV products can only be given by a healthcare provider. It’s not clear if taking L-arginine by mouth helps.
High blood pressure during pregnancy. Taking L-arginine by IV can reduce blood pressure in pregnancy. It’s unclear if taking L-arginine by mouth lowers blood pressure during pregnancy, but it might decrease the need to take blood pressure lowering drugs. IV products can only be given by a healthcare provider.
Possibly Ineffective for:
Long-term kidney disease (chronic kidney disease or CKD). Taking L-arginine by mouth or by IV doesn’t improve kidney function in most people with CKD.
High cholesterol. Taking L-arginine by mouth doesn’t help to lower cholesterol levels.
Heart attack. Taking L-arginine by mouth doesn’t seem to help prevent a heart attack. It also doesn’t seem to help treat a heart attack after it occurs. In fact, there is concern that L-arginine might be harmful for people after a recent heart attack. Do not take L-arginine if you have had a recent heart attack.
Tuberculosis. Taking L-arginine by mouth along with standard treatment for tuberculosis does not seem to help improve symptoms or clear the infection.
Wound healing. Taking L-arginine by mouth does not seem to improve wound healing.
There is interest in using L-arginine for a number of other purposes, but there isn’t enough reliable information to say whether it might be helpful.
Side Effects
When taken by mouth: L-arginine is possibly safe for most people when taken short-term. It can cause some side effects such as stomach pain, bloating, diarrhea, and low blood pressure.
When applied to the skin: L-arginine is possibly safe for most people when used short-term. It’s also possibly safe when used in a toothpaste short-term.
When inhaled: L-arginine is possibly safe for most people when used short-term.
