Health Benefits of L-Arginine

L-arginine is one form of arginine, an amino acid that is one of the building blocks of protein. Arginine is a non-essential amino acid because most humans can make it in their bodies. Infants and children may not be able to synthesize enough of it, but it is present in many protein-rich foods. 

L-arginine is present in most human tissues and bodily fluids. It plays a role in ridding the body of waste. It may also combat fatigue and boost the immune system.

One of the most important roles that L-arginine plays in the body is the production of nitric oxide. Because nitric oxide relaxes blood vessels, researchers hoped L-arginine supplements might help people with heart and circulatory problems. They have done many studies with arginine, but results have been mixed. 

Health Benefits

Although L-arginine may benefit the heart, it is not beneficial in all circumstances. One clinical trial tested whether L-arginine would help people recover from a heart attack. It was called off after several test subjects died.

Arginine does not seem to improve athletic performance. It also does not improve the function of healthy blood vessels.

Still, L-arginine may be beneficial in certain circumstances, including these: 

Erectile Function

Because L-arginine relaxes blood vessels, it may help men whose erectile dysfunction (ED) is due to poor blood flow. It may increase the effectiveness of medications like sildenafil (Viagra). Taking L-arginine with medication for ED could cause blood pressure to go too low. Talk to your doctor before using arginine for ED.

Blood Pressure

L-arginine supplements may lower blood pressure. An analysis of 11 studies showed that arginine lowered both systolic and diastolic blood pressure.

Healthy Endothelium

The endothelium is the membrane that lines blood vessels. A smooth, healthy endothelium means less chance of heart attack or stroke. L-arginine may improve endothelial health and lessen chest pain caused by poor circulation. It may also improve blood flow to the extremities.

Health Risks

L-arginine has the possibility of interacting with a long list of medications, mostly drugs for heart or circulation problems. If you take medications for diabetes and use L-arginine, your doctor may need to adjust the dosage of your diabetes drugs. L-arginine may also interact with herbs and other supplements.

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L-arginine is generally safe for most uses. If you take other medications for your heart, talk to your doctor before taking L-arginine. You should also stop taking L-arginine two weeks before having surgery. L-arginine may not be safe for children. Women who are pregnant or breast-feeding should check with a health care provider before taking L-arginine. 

In addition, L-arginine should not be used by those with certain conditions, including these: 

Asthma or Allergies

Taking L-arginine could result in an allergic reaction. It might also cause a narrowing of the airways, resulting in difficulty breathing.

Herpes  

Arginine could trigger an outbreak of the virus that causes genital herpes or cold sores. The virus needs arginine to multiply.

Amounts and Dosage

The appropriate dosage of L-arginine depends upon the reason you are taking it. Dosage can vary from a few grams daily up to 24 grams. Ask your doctor what dosage is right for you. 

Arginine is abundant in many foods, including red meat, fish, poultry, soy, whole grains, nuts, beans, and dairy products. 

WebMD Medical Reference Reviewed by Dan Brennan, MD on November 07, 2020

Sources

SOURCES:

American Heart Journal: "Effect of oral L-arginine supplementation on blood pressure: a meta-analysis of randomized, double-blind, placebo-controlled trials."

Circulation: "Long-term l-Arginine Supplementation Improves Small-Vessel Coronary Endothelial Function in Humans."

Clinical Science: "Dose-related effect of intravenous L-arginine on muscular blood flow of the calf in patients with peripheral vascular disease: a H215O positron emission tomography study."

Journal of the American Medical Association: "L-Arginine Therapy in Acute Myocardial Infarction: The Vascular Interaction With Age in Myocardial Infarction (VINTAGE MI) Randomized Clinical Trial."

Journal of Cardiovascular Pharmacology: "Effects of in vivo and in vitro L-arginine supplementation on healthy human vessels."

Mayo Clinic: "L-arginine."

NIH: "Dietary Supplements for Exercise and Athletic Performance."

NIH MedlinePlus: "L-arginine."

NIH PubChem: "Arginine."

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