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Natural Health Products

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Common Name(s)


Scientific Name(s)

(s)-2-Amino-5-[(aminoiminomethyl)amino]pentanoic acid, L-arginine

General Information

L-arginine was first isolatedisolatedto separate, strain, or extract in 1886, reportedly from a plant in the legume family. It is an amino acid (a chemical building block). The body usually makes enough L-arginine, but occasionally supplementation is needed. L-arginine can found in red meat, poultry, fish, and dairy products.

L-arginine is converted in the body into a chemical called nitric oxide. Nitric oxide helps blood flow by relaxing and widening blood vessels. L-arginine also stimulates the release of other substances in the body, such as growth hormones and insulin.

How is this product usually used?

L-arginine can be extractextractto get, separate, or isolate a desired active ingrediented from natural sources or made in the laboratory.

It is made into supplements of different forms such as chewable tablets, caplets, capsules, lozenges, powders, and liquids.

The dose for L-arginine ranges from 6 g to 21 g per day, with no more than 8 grams in a single dose. For protein synthesis, smaller doses may be recommended.

Your health care provider may have recommended using this product in other ways. Contact a health care provider if you have questions.

What is this product used for?

L-arginine may help people with stable cardiovascular (heart) disease to be able to exercise more. It is also a non-essential amino acid that is involved in protein synthesis in the body.

Research suggests that L-arginine may be helpful for those with heart conditions such as coronary artery disease, angina, or atherosclerosis (hardening of arteries). It is effective as a protein synthesis supplement.

People have also used L-arginine to prevent the common cold, improve kidney function after kidney transplant, improve athletic performance, boost the immune system, and improve pre-eclampsia (high blood pressure during pregnancy). It has also been used by people for erectile dysfunction, male infertility, and dementia.

Research suggests that L-arginine may help with erectile dysfunction.

There is not enough evidence available to assess whether L-arginine is beneficial for other uses.

Your health care provider may have recommended this product for other conditions. Contact a health care provider if you have questions.

What else should I be aware of?

No serious side effects have been reported for L-arginine. Side effects sometimes seen include stomach upset, nausea, diarrhea, bloating, and rash.

If you experience a severe allergic reaction (swelling of face and throat, difficulty breathing) to L-arginine, stop using the supplement and seek medical help right away.

If you have any sort of cardiovascular disease, speak with your doctor about using L-arginine, especially if you are using it for more than 6 weeks. If your condition worsens at any time, see your doctor. If you are trying to increase your physical activity, talk to your doctor before you start.

There have been reports of increased rates of death following a heart attack when L-arginine is used in high doses (3 g of L-arginine 3 times daily for up to 6 months) with other post-heart-attack medications. If you have recently had a heart attack, do not use L-arginine supplements.

L-arginine seems to lower blood pressure. When taken with other blood-pressure-lowering medications, it may cause your blood pressure to drop too low. Do not take L-arginine with blood-pressure-lowering medications without first speaking with your doctor.

L-arginine can be converted to nitric oxide in your body and can add to the effects of nitrate medication (e.g., nitroglycerin), increasing the chance of dizziness and lightheadedness.

Consult your doctor if you are taking blood thinners or medications for heart disease or erectile dysfunction.

L-arginine can make airway swelling worse in people with asthma. If you have asthma, consult with your doctor before you start taking L-arginine.

It is not known how safe L-arginine is for use by pregnant and breast-feeding women. Talk to your doctor if you are pregnant or breast-feeding before using this supplement.

Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.


  1. MedlinePlus – National Library of Medicine. L-arginine., accessed 7 August 2012.
  2. Natural Standard – the Authority on Integrative Medicine. Arginine., accessed 7 August 2012.
  3. Health Canada. Drugs & Health Products. Monograph – Arginine, L-., accessed 7 August 2012.
  4. Natural Medicines Comprehensive Database. L-Arginine full monograph., accessed 20 September 2012.

All material © 1996- MediResource Inc. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.