How to Take L-Arginine

Arginine is an amino acid that is typically sold in supplement form as L-arginine. According to the National Institutes of Health (NIH), most people do not need arginine supplements because is is found in many common foods. The NIH has found that arginine may be useful in treating heart disease and clogged arteries because it prompts the blood vessels to relax, although more research is needed to prove this connection. Additionally, arginine is often used in bodybuilding due to its role in protein creation in the body.

Things You’ll Need

  • Talk to your doctor before you start taking arginine supplements. The NIH has found that arginine can interact with many different medications, including Viagra, Zantac and even over-the-counter drugs like aspirin and ibuprofen. Your doctor can determine if arginine supplements are safe for your condition.
  • Do not use arginine if you are under 18, pregnant or breast-feeding. The effects of this supplement on these groups have not been studied extensively.
  • Take 2 to 3 grams of arginine up to three times per day, according to NIH guidelines. Arginine supplements typically come in capsule form and should be taken with a glass of water along with a meal. Since the size of arginine supplements may vary based on the manufacturer, follow individual product instructions or the advice of your doctor.
  • Stop taking arginine supplements if you develop any troubling side effects. Common side effects include upset stomach, cramping and increased frequency of bowel movements. Arginine may also increase potassium levels and cause low blood pressure.
  • Do not take arginine supplements if you also take ginkgo biloba supplements. Arginine may increase your risk of bleeding and it appears that risk is increased when taken along with ginkgo biloba.
  • Try to get arginine from whole foods if you can. Many types of nuts are good sources of arginine, especially walnuts, pecans and hazelnuts. Brown rice, barley, raisins and oats are also good dietary sources of this amino acid.

When to Take L-Arginine?

Arginine and ornithine are amino acids that are generally used by weightlifters to help repair and strengthen muscle tissue after weight lifting. The popular muscle building supplement creatine is a product of arginine; a deficiency of either amino acid can unsurprisingly result in muscle weakness. In order to use arginine and ornithine to their fullest potential as muscle builders, it’s important to know how much to take and when.

For a two-hour period following an intense workout, the body experiences increased testosterone and growth hormone production. In that two-hour period, supplemental arginine and ornithine dosages can help increase the production of protein synthesis and muscle growth.

The best way to utilize arginine and ornithine as growth hormone stimulants is to take a dose immediately following a period of strenuous exercise, and another dose at bedtime on an empty stomach. Additionally, nutritionist Dr. Michael Colgan recommends taking arginine and ornithine regularly for two months while engaged in a steady workout regimen, then stopping the dosages for two months, before starting the dosage cycle again.

Colgan delineates appropriate levels of arginine and ornithine dosages in “Optimum Sports Nutrition: Your Competitive Edge.” According to Colgan, a week of strength training totaling between four and 10 hours, for a person weighing between 170 and 220 lbs., would require approximately 9 grams of a combined arginine/ornithine supplement. For a total strength training week of 11 to 17 hours, the dosage should be increased to 12 grams of arginine/ornithine. Last, for a strength-training week falling between 18 and 24 hours, the proper dosage would be 15 grams.

The pituitary gland supplies the growth hormone that facilitates the formation of tissue and bone matter, which are made from amino acids. Without enough ornithine, the pituitary gland couldn’t produce the growth hormone necessary to repair the muscle tissue that’s injured during exercise. While ornithine is twice as effective in this regard than arginine, the two amino acids are most effective in stimulating muscle tissue repair when working in tandem.

According to a study referenced by the U.S. National Library of Medicine, adult males who participated in a five-week strength-training program, and who were given 1-2 gram dosages of arginine and ornithine during that time, showed noticeably improved levels of total strength and lean body mass. The study also determined that arginine and ornithine helped suppress the tissue breakdown that accompanies chronic stress.

L-Arginine Treatments

L-arginine, a dietary supplement available over the counter, is an amino acid used by the body as a chemical building block to produce nitric oxide. Nitric oxide opens blood vessels wider, enhancing circulation, and stimulates the release of insulin, growth hormone and other substances in the body. Many scientific studies of the effects of L-arginine have been done and are continuing. Evidence of L-arginine’s effectiveness in treating different conditions has varied.

Cardiovascular Disease

Adding L-arginine to conventional treatment for congestive heart failure seems to boost elimination of the extra fluids that cause the problem in CHF, but it doesn’t always improve quality of life or toleration of exercise for these patients. L-arginine seems to improve quality of life, exercise tolerance and effectiveness of nitroglycerin therapy as well as decrease symptoms for patients with angina, but doesn’t seem to decrease the actual disease. In a 2006 study in the Journal of the American Medical Association, L-arginine supplements did not improve vascular stiffness after myocardial infarction, and the study was discontinued after 8.6 percent of patients given L-arginine died while none in the control group died. Researchers concluded L-arginine should not be given to patients who have had acute myocardial infarction.

Sexual Dysfunction

A dose of five grams per day might be effective in treating male erectile dysfunction because the erectile process requires nitric oxide synthesized by L-arginine, but a 1999 clinical trial testing a lower dose in humans showed no difference between L-arginine and a placebo. There is insufficient evidence that L-arginine might improve female sexual dysfunction.


A 2001 study showed that lean patients with Type 2 diabetes had improved insulin sensitivity and decreased systolic blood pressure when taking 9 grams of L-arginine daily for a month. No changes were shown in hemoglobin, weight, diastolic blood pressure, serum potassium or heart rate. A study published in the June 13, 2006 American Journal of Physiology showed that the addition of 8.3 g L-arginine per day increased the effectiveness of a low calorie diet and exercise program for obese Type 2 diabetics. Topical application of L-arginine to the feet seems to improve circulation in diabetics, which might help prevent foot ulcers. But injecting L-arginine under the skin near an ulcer doesn’t seem to shorten healing time or reduce the chance of later amputation.


Taking L-arginine with eicosapentaenoic acid (EPA) and ribonucleic acid (RNA) before or after surgery seems to help shorten recovery time, ward off infections and improve wound healing. HIV-negative tuberculosis patients showed higher sputum conversion rates, increased weight gain and faster reduction of symptoms such as cough in a 2002 study, but HIV-positive patients in the same study showed no such results. L-arginine seems to help with healing of bone, burns, tendons, wounds and the gastrointestinal tract.


A 2000 study published in the Journal of Parenteral and Enteral Nutrition showed that L-arginine combined with hydroxymethylbutyrate (HMB) and glutamine and given orally as a dietary supplement slowed muscle wasting and improved lean body mass and immunity in HIV and AIDS patients.

Premature Infants

Studies have shown L-arginine reduces the risk of severe and damaging inflammation of the digestive tracts of premature infants. Nitric oxide is produced in the intestines to protect the digestive system from inflammation, but very low birth weight and preterm babies who develop the inflammation are reported to have low concentrations of arginine.

Interactions and Adverse Effects

L-arginine interacts with prescriptions to reduce blood pressure and increase blood flow to the heart. Since L-arginine and Sildenafil (Viagra) can both reduce blood pressure, caution should be used in combining them. Oral use of L-arginine has sometimes resulted in nausea and diarrhea. Although solid evidence is lacking, it is believed L-arginine can worsen sickle cell crisis and induce the outbreak of herpes symptoms. Intravenous administration of high dosage L-arginine has caused metabolic acidosis. Nitric oxide in high concentration is considered toxic to brain tissue.

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