Health Benefits of L-Arginine By Anthea Levi, RD Anthea Levi, RD Anthea Levi is a registered dietitian (RD) and reporter with more than 6 years of experience writing for major health outlets including Health magazine, BuzzFeed, Eat This, Not That!, and Livestrong. health's editorial guidelines Updated on May 20, 2024 Medically reviewed by Kristie Reed, PharmD Medically reviewed by Kristie Reed, PharmD Kristie Reed, PharmD, oversees emergency, general medical, surgical, psychiatric care, and oncology medication as the pharmacy director of a community hospital. Dr. Reed specializes in IV medications. learn more In This Article View All In This Article Supports Healthy Blood Pressure May Enhance Exercise Performance Reduces Chest Pain Improves Erectile Dysfunction May Lower Risk of Necrotizing Enterocolitis How to Take It Safety Side Effects Close fcafotodigital / Getty images L-arginine is a type of amino acid. Amino acids are the building blocks of protein, which is key for the health of your muscles and immune system. Certain amino acids may serve additional purposes. For instance, L-arginine supports healthy blood pressure levels and helps treat erectile dysfunction. L-arginine is a vasodilator, meaning it can help improve blood circulation and bring more oxygen to muscles throughout the body. L-arginine is a non-essential amino acid, which means the body naturally produces the substance on its own. The body does this by converting L-citrulline, another amino acid, to L-arginine in the kidneys. L-arginine is also naturally found in protein-rich foods, such as meat, dairy, nuts, and seeds. But supplementing with L-arginine may bring even more benefits and be helpful in the management of certain health conditions. Dietary supplements are minimally regulated by the FDA and may or may not be suitable for you. The effects of supplements vary from person to person and depend on many variables, including type, dosage, frequency of use, and interactions with current medications. Please speak with your healthcare provider or pharmacist before starting any supplements. Supports Healthy Blood Pressure In the body, L-arginine is converted into nitric oxide, a molecule that widens blood vessels to improve blood flow. This can help lower blood pressure levels and maintain healthy circulation. Research has shown L-arginine can reduce systolic and diastolic blood pressure in people with or without high blood pressure. Some small studies suggest intravenous (IV) L-arginine supplementation, which is treatment delivered directly into the vein through an IV drip, may also help manage high blood pressure. It may also help treat preeclampsia, which is high blood pressure during pregnancy. There is some evidence taking oral L-arginine supplements early in pregnancy may help prevent the onset of preeclampsia. However, more research is needed to confirm this potential benefit. May Enhance Exercise Performance Since L-arginine helps deliver blood, oxygen, and other nutrients to working skeletal muscles, it’s possible the amino acid may improve exercise performance. L-arginine also helps speed up the removal of materials like lactate and ammonia from the body, which can lead to fatigue during physical activity. Plus, L-arginine aids in the formation of creatine, another amino acid that provides fuel to muscles during high-intensity exercise. However, studies in this area have produced conflicting results. Some researchers have concluded the evidence is lacking on whether L-arginine supplementation improves athletic performance or recovery. Reduces Chest Pain Angina is a type of chest pain caused by insufficient blood flow to the heart. L-arginine supplementation may help manage symptoms associated with angina and improve exercise tolerance for people with angina. This benefit may be due to L-arginine’s ability to promote healthy circulation. However, there is not enough evidence to show that the amino acid helps treat narrowed blood vessels that may be related to angina. Improves Erectile Dysfunction L-arginine may help boost sexual function, especially when paired with other erectile dysfunction (ED) medications. Research has shown L-arginine supplements taken in combination with ED medications like PDE5 inhibitors can significantly improve sexual function in people diagnosed with ED. When L-arginine is converted into nitric oxide, it can help promote blood flow, bring more oxygen throughout the body, and smooth muscle relaxation. All of these factors are essential for erections. May Lower Risk of Necrotizing Enterocolitis Necrotizing enterocolitis (NEC) is a condition that can affect the digestive systems of premature infants. Research has shown oral L-arginine supplementation significantly reduced the risk of NEC in premature infants when compared to a placebo. However, more studies on larger populations are needed to recommend this as a treatment. How to Take L-Arginine Supplemental L-arginine can be given orally in a capsule, topically as a gel or cream, or intravenously in a clinical setting. L-arginine can also be consumed through several protein-rich food sources. The amino acid is found naturally in the following foods: MeatPoultry (chicken, eggs)FishNuts and seedsLegumes (beans, lentils) Dosage Most research suggests L-arginine supplements are well-tolerated in doses of up to 9 grams (g) per day. However, L-arginine supplements have been shown to be safe to take in oral doses ranging from 1.5 to 24 g daily for up to 18 months. You can also follow the dosing instructions provided on the product’s label. Optimal dosages may vary based on age, certain conditions, and the reason for supplementation. Speak with your healthcare provider to discuss which amount of L-arginine supplementation may be best for you. Is L-Arginine Safe? Oral L-arginine is considered safe when taken in the appropriate amounts for up to 18 months. The amino acid may be safe to take during pregnancy when consumed in low doses for a short duration. However, it’s best to speak to a healthcare provider before starting a new supplement while pregnant. People who are breastfeeding should avoid the use of L-arginine since there is not enough research to know if it’s safe for this population. Those who have high blood pressure or a higher risk for heart disease should also not take animal-derived L-arginine supplements. Research has shown the supplement could potentially worsen risk factors for these conditions. Potential Drug Interactions L-arginine may interact with certain medications, including: Antihypertensive medications: Since L-arginine may lower blood pressure, combining the supplement with any blood pressure medication may lead to blood pressure levels that are too low (hypotension). Diuretics: Taking L-arginine along with potassium-sparing diuretics could potentially increase the risk of dangerously high potassium levels in the blood (hyperkalemia). Blood thinners: When taken with anticoagulant medications, L-arginine may increase the risk of excessive bleeding or bruising. Nitrates: The body converts L-arginine into nitric oxide which widens blood vessels, so taking the supplement with nitrate medications—vasodilators often used for angina and other heart conditions—may increase the effect. Diabetes drugs: L-arginine may lower blood sugar levels, so combining the supplement with diabetes drugs, including insulin, could increase the risk of too-low levels of glucose in the blood (hypoglycemia). For the same reasons, L-arginine may also interact with certain supplements or herbs, including those that help lower: Blood pressure, such as niacin or stinging nettles Clotting risk, such as garlic, ginger, or gingkoBlood glucose levels, such as cinnamon, chromium, or bitter melon What to Look For The U.S. Food and Drug Administration (FDA) does not regulate supplements in the same way they regulate food and drugs. When purchasing a supplement, look for brands that have undergone third-party testing. These products will have seals of the third-party testing organization on the bottle. For example, the National Sanitation Foundation (NSF) and the U.S. Pharmacopeia (USP) are two groups that assess supplements for purity and quality. Can You Take Too Much L-Arginine? There is currently no set upper intake level for L-arginine. Clinical research has examined the use of L-arginine in doses of up to 24 g per day. Taking over 30 g of L-arginine may be potentially unsafe. If you have questions about a safe dosage of a supplement for you, talk to your healthcare provider. Side Effects of L-Arginine Although L-arginine is generally well tolerated, some people may experience adverse reactions to the supplement. The most common side effects of L-arginine supplementation include: Abdominal painAbdominal distention or bloatingNauseaDiarrhea Low blood pressure HeadachesFlushing Insomnia Speak to a healthcare provider if you experience any adverse reactions from taking L-arginine. A Quick Review L-arginine is an amino acid the body naturally creates, but it can also be found in protein-rich foods. It’s also possible to supplement with L-arginine. Research suggests L-arginine supplementation may be beneficial in the management of conditions like hypertension and erectile dysfunction. Although L-arginine is typically well tolerated, side effects like gastrointestinal discomfort and low blood pressure are possible. Always speak to your healthcare provider before integrating a new supplement to determine what form and dosage may be right for you. Read more: Wellness Nutrition Vitamins and Supplements Was this page helpful? Thanks for your feedback! Tell us why! Other Submit 12 Sources Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. National Institutes of Health. Dietary supplements for exercise and athletic performance. MedlinePlus. L-arginine. Natural Medicines. L-arginine. Brooks JR, Oketch-Rabah H, Low Dog T, et al. Safety and performance benefits of arginine supplements for military personnel: A systematic review. Nutr Rev. 2016;74(11):708-721. doi:10.1093/nutrit/nuw040 Xu Z, Liu C, Liu S, Zhou Z. Comparison of efficacy and safety of daily oral L-arginine and PDE5Is alone or combination in treating erectile dysfunction: A systematic review and meta-analysis of randomised controlled trials. Andrologia. 2021;53(4):e14007. doi:10.1111/and.14007 Menafra D, de Angelis C, Garifalos F, et al. Long-term high-dose l-arginine supplementation in patients with vasculogenic erectile dysfunction: a multicentre, double-blind, randomized, placebo-controlled clinical trial. J Endocrinol Invest. 2022;45(5):941-961. doi: 10.1007/s40618-021-01704-3 Shah PS, Shah VS, Kelly LE. Arginine supplementation for prevention of necrotising enterocolitis in preterm infants. Cochrane Neonatal Group, ed. Cochrane Database Syst Rev. 2017;2017(4). doi:10.1002/14651858.CD004339.pub4 Bahadoran Z, Mirmiran P, Tahmasebinejad Z, Azizi F. Dietary L-arginine intake and the incidence of coronary heart disease: Tehran lipid and glucose study. Nutr Metab (Lond). 2016;13(1):23. doi:10.1186/s12986-016-0084-z Kiani AK, Bonetti G, Medori MC, et al. Dietary supplements for improving nitric-oxide synthesis. J Prev Med Hyg. 2022;63(2 Suppl 3),E239–E245. doi:10.15167/2421-4248/jpmh2022.63.2S3.2766 Lee PM, Gerriets V. Nitrates. In: StatPearls. StatPearls Publishing; 2023. National Institutes of Health. Dietary supplements: Background information. National Institutes of Health. Botantical dietary supplements: Background information. Shop Products We Recommend Advertiser Disclosure × If you click on the links provided in the table, Health may receive compensation.