Nitric Oxide Benefits and Risks

Nitric oxide supplements are often used to help the heart, lower high blood pressure, treat erectile dysfunction, and boost athletic performance. Nitric oxide is a natural gas in the body that helps relax blood vessels and improve blood flow.

Nitric oxide supplements don’t contain actual nitric oxide gas. Instead, they have amino acids like L-arginine, L-citrulline, and nitrates, which the body can use to make nitric oxide. Amino acids are the building blocks of proteins.

In the United States, the Food and Drug Administration (FDA) does not regulate dietary supplements the way it regulates prescription medications. As a result, some supplement products may not contain the ingredients listed on the label. When choosing a supplement, look for products independently tested or certified by organizations such as the National Sanitation Foundation (NSF), United States Pharmacopeia (USP), or ConsumerLab. For personalized guidance, consult your healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.

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Nitric oxide plays a vital role in many body functions. Some research shows that nitric oxide supplements may help prevent disease by acting as powerful antioxidants.

Nitric oxide may offer the following benefits:

Regulates blood pressure: Nitric oxide makes your blood vessels relax, making it easier for blood to flow and keeping blood pressure in a healthy range. Hypertension (high blood pressure) can develop if your body doesn't make enough nitric oxide. Taking nitric oxide supplements may help improve circulation and keep your blood vessels strong.

Fights damage from free radicals: Your body is always fighting off harmful molecules called free radicals that damage cells and contribute to inflammation and disease. Nitric oxide works like a shield, protecting cells from this damage. This may help lower the risk of heart disease, brain problems, and even some types of cancer.

Increases exercise endurance: By improving blood flow, nitric oxide helps your muscles get more oxygen when you work out. This means you can exercise longer without becoming fatigued, and recover faster afterward. It also reduces muscle soreness and helps prevent injuries.

Boosts brain power: Your brain needs a steady supply of oxygen and nutrients to function well. Nitric oxide improves blood flow to the brain, which can sharpen memory, focus, and learning. It may also help protect the brain from degenerative diseases like Alzheimer's as you get older.

Controls blood sugar and weight: Nitric oxide plays a role in how your body handles sugar and fat. When your body doesn't make enough nitric oxide, it can contribute to problems like obesity and diabetes. Keeping nitric oxide levels high may help your body burn fat and use sugar more effectively.

Reduces diabetes complications: High blood sugar can damage blood vessels and nerves over time, leading to serious complications like kidney disease, blindness, and limb amputations. By improving blood flow and protecting blood vessels, nitric oxide may help reduce these risks.

Improves sense of smell: Nitric oxide helps deliver oxygen and nutrients to the olfactory system, which is responsible for detecting smells. It also supports nerve function and regeneration, which can help repair damaged olfactory receptors. Additionally, nitric oxide plays a role in neurotransmission, helping the brain process scent signals more effectively.

Protects skin from sun damage: Nitric oxide helps deliver oxygen and nutrients to the skin, supporting its repair. Its antioxidant properties may reduce damage caused by UV radiation and support the skin's natural defense mechanisms, reducing the risk of sunburn and skin cancer.

Improves sexual health: Nitric oxide improves blood flow to the whole body, including the reproductive organs. For men, boosting blow flow with nitric oxide can help with erectile dysfunction. For women, it may improve menstrual cramps, ovarian health, and fertility.

Supports digestion and gut health: Nitric oxide helps your intestines move food smoothly through your system. It also protects your stomach and intestines from harmful bacteria and irritation. This can help prevent problems like constipation, bloating, and irritable bowel syndrome (IBS).

Helps you breathe better: Nitric oxide relaxes the muscles in your lungs, making it easier to breathe. This can be particularly helpful for people with lung conditions like COPD.

Speeds up wound healing: If you get a cut or injury, nitric oxide helps your body heal faster by improving blood flow and helping new cells grow. This is especially helpful for people with diabetes or slow-healing wounds. It may also help you heal after surgery or injuries.

May help prevent cancer: Some research suggests that nitric oxide can slow down the growth of cancer cells. It helps stop tumors from forming new blood vessels, which they need to grow. While more studies are needed, nitric oxide might be part of future cancer treatments.

Prevents altitude sickness: Nitric oxide improves how your body adapts to high-altitude environments. It helps improve blood flow and breathing at altitude and prevents altitude sickness. This can be useful for hikers and people living in or traveling to high-altitude areas.

While it's clear nitric oxide is important for the body, more high-quality studies are needed to confirm the benefits and effectiveness of nitric oxide supplements.

Studies show that taking up to 30 grams of L-arginine per day is safe for most adults, but it can cause side effects like stomach pain and low blood pressure. The safest way to support nitric oxide levels is by getting it through your diet. If you're considering taking a supplement, consult a healthcare provider first.

You can increase nitric oxide levels by taking supplements, eating nitrate-rich foods, exercising, and getting sunlight. Techniques like acupuncture and deep breathing may also help, but more research is needed.

Despite their name, nitric oxide (NO) supplements do not contain nitric oxide gas. Instead, they contain compounds that the body can convert into nitric oxide, such as amino acids like L-arginine and L-citrulline, as well as nitrates.Nitric oxide supplements are commonly available in capsules, but other forms include:

Lozenges and beetroot powders meant to boost nitric oxide are becoming widely available. However, many beet-based products lack detectable nitrate or nitrite, meaning they may not effectively boost nitric oxide levels. It’s important to choose supplements from reputable sources that preserve nitrate content.

L-arginine supplements, often marketed for athletic performance, should be used cautiously. While studies show potential benefits in reducing fat and improving metabolic health, long-term safe dosages are unclear.

The best form for you depends on personal preference and desired effects. Since different products may work differently, following label directions or a healthcare provider’s advice is essential.

Getting nitric oxide from food is the best way to support your body's natural production. While supplements can help certain people, most people can boost nitric oxide through diet alone.

Your body converts nitrates found in foods intro nitric oxide. Some of the best food sources of nitrates include:

A good tip is to eat at least one cup of dark greens or cruciferous vegetables daily. Choose raw or lightly steamed vegetables, as boiling can reduce nitrate levels.

Certain nutrients found in foods help protect and extend nitric oxide's effects, including:

Eating a mix of these foods daily can support healthy nitric oxide levels naturally, without the potential side effects of supplements.

In addition to diet, there are simple ways to naturally increase nitric oxide in your body.

There is no standard dosage for nitric oxide (NO) supplements since they contain different ingredients in varying amounts.

Research suggests that up to 30 grams per day of L-arginine is well-tolerated in adults, but excessive intake can increase the risk of liver or kidney damage and ischemic heart disease. Consulting a healthcare provider before use is recommended.

If you take a nitric oxide supplement, follow the product label instructions and consult a healthcare provider to ensure safety.

L-arginine and L-citrulline are generally considered safe, but nitric oxide supplements vary in ingredients and dosages, making it difficult to determine their overall safety.

More research is needed to understand the risks, toxicity, and potential for overdose with different nitric oxide supplements.

Taking too much may lead to severe side effects, similar to those seen with high nitric oxide levels. In extreme cases, excess nitric oxide could cause lung injury or methemoglobinemia—a condition where red blood cells struggle to transport oxygen.

Symptoms of methemoglobinemia include:

Nitric oxide (NO) supplements, as with many medications and natural products, may have side effects.

Common side effects of NO supplements may include:

Severe side effects are rare but can happen. These may include:

If you're having a severe allergic reaction or if any of your symptoms feel life-threatening, call 911 and get medical help right away.

Nitric oxide supplements might interact with the following:

It is essential to carefully read a supplement's ingredients list and nutrition facts panel to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.

A healthcare provider may advise against using nitric oxide supplements if any of the following applies to you:

Severe allergic reaction: Avoid NO supplements if you have a known allergy to them or their ingredients. If you're unsure if it's safe for you, ask a pharmacist, registered dietitian (RD) or registered dietitian nutritionist (RDN), or healthcare provider for more information.Pregnancy and breastfeeding: There is not enough research to confirm whether nitric oxide supplements are safe in people who are pregnant or breastfeeding. Before taking nitric oxide supplements, contact a healthcare provider to discuss the benefits and risks.

Children: There are a few nitric oxide supplements marketed for children. However, there is limited information about the effects and safety of nitric oxide supplements in children. Discuss the benefits and risks of these supplements with a healthcare provider.

Certain digestive system problems: Nitric oxide might affect the balance of water and electrolytes (salts) in your gut. If there is already an imbalance, you might have a higher likelihood of side effects from nitric oxide supplements. If you have a history of gastrointestinal issues, consult a healthcare provider before taking them.

Guanidinoacetate methyltransferase deficiency (GAMT): GAMT is a condition that runs in families. People with GAMT don't have a protein to convert arginine into creatine. Therefore, people with GAMT should avoid nitric oxide supplements, especially those that contain arginine.

Heart conditions: Healthcare providers are unlikely to recommend L-arginine if you have recently had a heart attack, as these supplements may worsen your heart condition, especially in older adults.

Low blood pressure: If you have low blood pressure, nitric oxide supplements may not be right for you. Consult a healthcare provider before taking them. Your provide will likely recommend that you stop taking nitric oxide before going into surgery.

Nitric oxide is a natural gas in your body that helps relax blood vessels and improve blood flow. Some research suggests that nitric oxide supplements may support heart health, enhance athletic performance, improve reproductive health, and even help prevent cancer.

Like most supplements, the risks and benefits of nitric oxide supplements are not fully understood, and they can have side effects. A safer and more reliable way to boost nitric oxide is through diet by eating nitrate-rich foods like beets and watermelon. Sun exposure and regular exercise can also naturally increase nitric oxide levels while providing additional health benefits.

The Department of Defense Dietary Supplement Resource: Operation Supplement Safety. Nitric oxide supplements.

Food and Drug Administration. Drugs@FDA: FDA-approved drugs.

United States Department of Agriculture. FoodData Central: Nitric oxide.

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

National Institutes of Health: Office of Dietary Supplements. Dietary supplement label database: nitric oxide.

LactMed. Nitric oxide.

Bryan NS. Nitric oxide deficiency is a primary driver of hypertension. Biochem Pharmacol. 2022;206:115325. doi:10.1016/j.bcp.2022.115325

Oregon State University. Say NO to disease: The benefits of nitric oxide.

Oyovwi MO, Atere AD. Exploring the medicinal significance of l-Arginine mediated nitric oxide in preventing health disorders. Eur J Med Chem Rep. 2024;12(1):100175. doi:10.1016/j.ejmcr.2024.100175

Zhang L, Fang F, Yao L, et al. Decreased nasal nitric oxide levels: a potential marker of decreased olfactory discrimination in chronic rhinosinusitis. J Laryngol & Otol. 2022;136(5):419-426. doi:10.1017/S0022215121003169

Hazell G, Khazova M, Cohen H, et al. Post-exposure persistence of nitric oxide upregulation in skin cells irradiated by UV-A. Sci Rep. 2022;12(1):9465. doi:10.1038/s41598-022-13399-4

Hotta Y, Kataoka T, Mori T, Kimura K. Review of a potential novel approach for erectile dysfunction: light-controllable nitric oxide donors and nanoformulations. Sex Med Rev. 2020;8(2):297-302. doi:10.1016/j.sxmr.2019.05.006

Andrabi SM, Sharma NS, Karan A, et al. Nitric oxide: physiological functions, delivery, and biomedical applications. Adv Sci (Weinh). 2023;10(30):2303259. doi:10.1002/advs.202303259

Idrizaj E, Traini C, Vannucchi MG, Baccari MC. Nitric oxide: from gastric motility to gastric dysmotility. Int J Mol Sci. 2021;22(18):9990. doi:10.3390/ijms22189990

Phillips DB, Brotto AR, Ross BA, et al. Inhaled nitric oxide improves ventilatory efficiency and exercise capacity in patients with mild COPD: A randomized-control cross-over trial. J Physiol. 2021;599(5):1665-1683. doi:10.1113/JP280913

Malone-Povolny MJ, Maloney SE, Schoenfisch MH. Nitric oxide therapy for diabetic wound healing. Adv Healthc Mater. 2019;8(12):e1801210. doi:10.1002/adhm.201801210

Cumpstey AF, Hennis PJ, Gilbert-Kawai ET, et al. Effects of dietary nitrate on respiratory physiology at high altitude - Results from the Xtreme Alps study. Nitric Oxide. 2017;71(1):57-68. doi:10.1016/j.niox.2017.10.005

McNeal CJ, Meininger CJ, Wilborn CD, Tekwe CD, Wu G. Safety of dietary supplementation with arginine in adult humans. Amino Acids. 2018;50(9):1215-1229. doi:10.1007/s00726-018-2594-7

Ma SX, Lee PC, Anderson TL, Li XY, Jiang IZ. Response of local nitric oxide release to manual acupuncture and electrical heat in humans: effects of reinforcement methods. Evid Based Complement Alternat Med. 2017;2017(1):4694238. doi:10.1155/2017/4694238

Iowa Health and Human Services. Methemoglobinemia.

Koolwal A, Manohar J. S, Rao TSS, et al. L-arginine and erectile dysfunction. Journal of Psychosexual Health. 2019;1(1):37-43: doi:10.1177/2631831818822018

Food and Drug Administration. Inomax label.

By Ross Phan, PharmD, BCACP, BCGP, BCPSRoss is a writer for Verywell and has years of experience practicing pharmacy in various settings, which currently include medical communications. She is also a board-certified clinical pharmacist, the founder of Off Script Consults, and director of the PharmacyChecker international verification program.