What Is L-arginine and Are Supplements Necessary?

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L-arginine, also known as arginine, is an amino acid that is necessary to make proteins in the body. It is classified as a semi-essential nutrient because the body normally makes enough to meet daily requirements, and it is abundant in a variety of foods, but supplementation may be necessary for some people, especially for those who eat poorly or suffer from a physical condition.

Arginine has many functions, including healing wounds, removing waste products and maintaining hormone and immune function. Hair loss, skin rash, poor wound healing, constipation and fatty liver are symptoms of a deficiency.

Foods high in arginine include dairy products, beef, pork, poultry, seafood, wheat germ, oatmeal, chick peas, walnuts, cashews, almonds, hazelnuts, pumpkin seeds, sunflower seeds and cooked soybeans.

Health Benefits

Supplementation may benefit the following health problems (more research is needed):


L-arginine is needed to make nitric oxide. Nitric oxide increases blood flow, keeps the walls of vessels from becoming too thick and stiff, prevents narrowing of the arteries and stops fatty deposits from adhering to the walls of blood vessels.

Conditions l-arginine may benefit include:

  • High blood pressure - It has been shown to slightly lower blood pressure in healthy people and in type 2 diabetics with mild high blood pressure.
  • Coronary artery disease (CAD) - Several studies suggest it may improve blood flow in arteries of the heart.
  • Chest pain associated with CAD (angina pectoris) - It appears to decrease symptoms, as well as improve quality of life, but it does not appear to improve the disease itself.
  • Congestive heart failure - It appears to help eliminate extra fluids, but does not always improve quality of life.

Individuals should not take l-arginine supplements after having a heart attack. In one study, not only did the supplement not show any significant improvements, six participants died and the study was terminated after six months. No participants taking the placebo died.

Erectile Dysfunction

Nitric oxide is also said to help treat erectile dysfunction by increasing blood flow in the male genitalia, similar to Viagra. Unlike arginine that makes nitric oxide, Viagra improves blood flow by blocking an enzyme that destroys nitric oxide.

Male Infertility

L-arginine is needed for the replication of cells, making it essential in sperm formation. According to one study involving 178 men with low sperm counts, 74 percent had significant improvement in sperm counts and motility. Supplementation is less likely to help if sperm counts are less than 20 million/ml.

Diabetes and Diabetic Complications

Some human studies suggest that arginine may decrease the severity of diabetes. It is also believed that supplementation may help in the prevention of long-term complications of diabetes, such as heart disease and nerve damage.

HIV Complications

When used with l-glutamine and beta-hydroxy-beta-methylbutyrate, arginine appears to increase body weight, mostly lean body mass. According to one study involving people with HIV who had lost at least 5 percent of their weight in a three month period, those who received the three supplements gained significantly more weight than those who took a placebo after eight weeks.

The three supplements also appear to improve the immune system in people infected with HIV.


Supplementation has also been used to prevent the common cold, treat migraines, promote wound healing and improve senile dementia.

Side Effects

In studies, supplementation was well tolerated by most people when taken for up to six months. Possible side effects include headaches, indigestion, nausea, bloating, diarrhea, low blood pressure, swelling in the legs, breathing problems and chest pain.


Children under the age of 18, women who are pregnant and women who are breastfeeding should not take arginine supplements.

Individuals with a history of genital herpes should not take because it may aggravate symptoms. In vitro studies have shown that HSV replication is dependent on adequate levels of arginine. Foods high in this nutrient should also be avoided, or greatly limited.

People with a bleeding disorder or who are taking anticoagulant or antiplatelet drugs should avoid use or be monitored closely by their health care provider because this supplement may increase the risk of bleeding.

People with a medical condition or who are taking medications should consult with a health care provider before taking supplements.


There is no well-established dose, but 2 to 3 grams three times a day is a common dose for adults (18 years and older).


Mayo Clinic: Arginine (L-arginine) - https://www.mayoclinic.com/health/l-arginine/NS_patient-arginine

Web MD: L-arginine - https://www.webmd.com/vitamins-supplements/ingredientmono-875-L-ARGININE.aspx?activeIngredientId=875&activeIngredientName=L-ARGININE

Drugs: L-arginine - https://www.drugs.com/npp/l-arginine.html

Michael Murray, N.D. and Joseph Pizzorno, N.D. “Encyclopedia of Natural Medicine” Prima Publishing 1998


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