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Nitric Oxide Supplements: Uses & How They Work

Kelly Brown MD, MBA

Reviewed by Kelly Brown MD, MBA

Written by Rachel Sacks

Published 05/22/2022

Updated 04/18/2024

Listen, guy. We're not trying to trigger PTSD from our organic chemistry days, but if you're a dude concerned about blood flow downstairs — and therefore, erection quality — you can't even begin to have the conversation about erectile dysfunction without talking about nitric oxide.

And we probably don’t need to tell you that. After all, googling natural treatments for erectile dysfunction has probably brought nitric oxide supplements to your attention. 

Available over-the-counter, many nitric oxide supplements claim to boost blood flow, giving you stronger erections and better physical performance and athletic performance (you remember the ad screaming at you through an incognito browser, we’re sure).

Do they work? Are they your key to better sex? It’s complicated. Below, we’ve explained: 

  • What nitric oxide is and how it’s necessary for your body

  • The science behind nitric oxide supplements

  • Whether or not they’re worth using for better physical health and erections 

Oh, and we’ve also shared a few other, evidence-based treatment options that you may want to consider if you suffer from erectile dysfunction (ED).

First things first: nitric oxide isn’t some BS supplement ingredient from a rainforest frog’s testicles — it’s real science. 

Nitric oxide is a gas naturally produced inside your body that works as a type of signaling molecule for your cells and organs. In fact, nitric oxide plays a role in almost every cellular and organ function in your body as it’s converted to nitrate. 

Its key role, however, is to regulate the tone and blood flow of your vascular system — the complex network of blood vessels that transports oxygen and nutrient-rich blood to your organs and is charged with removing waste products.

Nitric oxide is also known as a vasodilator. It’s a chemical that increases blood flow and promotes lower blood pressure through its effects on soluble guanylate cyclase (sGC), a type of enzyme found in the smooth muscle of your blood vessels. 

When soluble guanylate cyclase is active, your blood vessels can increase in size, allowing for better blood flow to certain parts of your body. 

That’s a lot of jargon to explain that nitric oxide helps blood more easily move to where it’s needed. And that’s really important when where you want the blood to go is into your penis for an erection.

Nitric oxide relaxes the vascular muscles in the arteries that supply your penis with blood when you’re sexually aroused.

This increase in blood vessel diameter and blood flow is what allows your penis to get firm and erect while you’re having sex. So yeah, that’s really, really important.

Because nitric oxide plays such a major role in healthy erections, medical conditions that reduce your production of nitric oxide can potentially contribute to erectile dysfunction. 

And the risks don’t stop at erectile efficiency. Low nitric oxide levels may also contribute to a higher risk of common heart health issues, such as cardiovascular disease.

Nitric oxide, it turns out, is clutch when you’re trying to get hard. Research has found that nitric oxide plays a key role in facilitating erections by relaxing the vascular muscle that supplies your penis with blood when you’re sexually aroused.

This increase in blood vessel diameter and blood flow is what allows your penis to stay firm and erect while you’re having sex. So yeah, that’s really, really important.

Because nitric oxide plays such a major role in healthy erections, medical conditions that reduce your production of nitric oxide can potentially contribute to erectile dysfunction. 

And the risks don’t stop at boner efficiency. Low nitric oxide levels may also contribute to a higher risk of common heart health issues, such as cardiovascular disease.

If you’re in this situation, you may be wondering how to pump some of this priming gas into your penis. That’s more complicated than it may seem.

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Nitric oxide supplements are exactly what they sound like — supplements that claim to increase levels of nitric oxide within your body. 

They’re available over-the-counter as pre-workout style powdered drinks, beetroot extracts or capsules, and can be purchased from drug stores, health food stores and, yes, even online. 

There’s a bit of a catch to these products, though, and it has to do with what’s actually inside these supplements.

Most of the time, dietary supplements have the same active ingredient as their name suggests. For example, creatine supplements contain creatine, and protein supplements contain different types of protein.

Nitric oxide supplements, on the other hand, contain active ingredients that are used within your body to supposedly increase its own nitric oxide production. 

More specifically, most nitric oxide boosters contain the active ingredients L-arginine and L-citrulline. These amino acids act as biological “building blocks” for nitric oxide within your body.

The idea behind these supplements is that giving your body the nutrients it needs to produce its own nitric oxide will increase nitric oxide levels.

Some research backs up this theory. With lots of dietary supplements, many of the studies used to support the idea that nitric oxide precursors boost nitric oxide production are animal research.

For example, one study published in 2014 in the journal Biochemical and Biophysical Research Communications found that oral use of the amino acids L-arginine and L-citrulline — the two amino acids typically used in nitric oxide supplements — increased nitric oxide levels in rats and rabbits.

But that’s not to say there aren’t some promising studies involving people on whether supplements can boost nitric oxide or not.

Prelox®, a combination of L-arginine aspartate and Pycnogenol® (another popular natural supplement otherwise known as maritime pine), was shown to support nitric oxide production in clinical trials.

Notably, a study looking at L-arginine and L-citrulline levels in men found that men with severe ED with an arteriogenic etiology had lower levels of these two amino acids, indicating a possible  nitric oxide synthesis related explanation.

Improved sexual function was also reported in nine patients who took L-arginine supplements to boost their nitric oxide levels.

And finally, a three-month trial using Pycnogenol to increase L-arginine and NO levels saw just over 92 percent of men with ED achieve normal erections.

You might be thinking, “Hey, all this research on humans looks good! 92 percent is a great number for erections!” And you’re not wrong.

But many of these studies were on the smaller side. So while they’re promising, it doesn’t necessarily mean that supplements for nitric oxide work the same way in humans.

A review published in the journal Sports Medicine found that nitric oxide supplements do appear to offer exercise-related benefits, including increased exercise performance.

It’s worth noting that these effects were observed in people with low to moderate prior training — in more highly trained people, nitric oxide supplements didn’t show any effects.

Choose your chew

Dietary supplements don’t need to have the same proof about their claims that medications need to have. 

And as such, there aren’t any nitric oxide supplements that have been approved by the FDA to treat erectile dysfunction , which means your provider probably won't be raving about how excited they are to recommend them to you.

But these supplements may have some effect on ED. Although nitric oxide supplements shouldn’t be viewed as a treatment for ED, a small amount of research suggests that there may be benefits of nitric oxide for erections and male sexual function. 

  • An article published in the journal Future Science OA looked at several studies of L-arginine supplements and L-citrulline supplementation, noting that some had shown improvements in erection hardness scores (EHS) and other measures of erectile function.

  • A small study published in the Journal of Sex & Marital Therapy also found that use of a dietary supplement containing L-arginine produced improvements in erectile health and sexual function in men with ED. 

  • Some research suggests that beetroot and beetroot juice offer a natural and antioxidant-rich source of nitric oxide, which may offer benefits in treating certain health conditions — potentially including ED.

The research we have looks promising, but we need a lot more before anyone can say anything definitive about the efficacy of these supplements.

One of the biggest problems with supplements is that, because the FDA doesn’t have the same grip on them, they can be less predictable (and less safe) than medications.

Nitric oxide supplements could boost nitric oxide in your body, but they may cause unwanted effects when you take them. For nitric oxide, those side effects may include:

  • Increased risk or worsening of heart failure

  • Hypotension, or low blood pressure

  • Pulmonary vasospasm

If you experience dizziness, chest pain or other issues when taking nitric oxide, seek immediate medical attention.

Nitric oxide supplements may work, but if you're looking for more proven ED treatments, options abound to improve blood flow. Medications approved by the FDA and changes to your lifestyle can do more than supplements in almost all cases. Let’s look at how.

FDA-Approved ED Medications

Currently, the FDA has approved four science-backed oral medications for erectile dysfunction

These medications belong to a class of drugs called PDE5 inhibitors, which work by preventing the enzyme phosphodiesterase-5 from restricting blood flow to the erectile tissue located inside your penis.

They can be taken as-needed 30 to 60 minutes before sex, making it easy to deal with erectile dysfunction (ED) and improve your sexual performance.

The FDA has also approved an injectable medication, alprostadil, for ED, and it has recently authorized a topical gel for ED.

Lifestyle and Habits

You can also reduce your risk of dealing with erectile dysfunction by making healthy changes to your habits and lifestyle. These changes can be particularly important, since erectile dysfunction is often the “canary in the coal mine” for cardiovascular disease.

Several things may help improve your sexual function and prevent ED. For example: 

  • Exercising regularly

  • Maintaining a healthy weight

  • Limiting your alcohol intake

  • Quitting smoking 

  • Avoiding illicit drugs

Our guide to naturally protecting your erection goes into more detail about these techniques and other approaches that you can use to improve your sexual function naturally.

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Nitric oxide is an important signaling molecule that your body uses for a wide variety of different functions, including supplying blood to your penis when you’re aroused. It’s certainly an essential biological ingredient. But supplementing it isn’t a plan without risks.

Consider the following when weighing your choices:

  • Research on nitric oxide supplements and ED is limited, but some studies suggest that the L-arginine and L-citrulline found in nitric oxide supplements help to treat ED.

  • Using a nitric oxide supplement may generally help to strengthen your erections and improve your sexual function. 

  • However, you’ll notice the biggest improvements from evidence-based medications like sildenafil (Viagra), tadalafil (Cialis) and avanafil (Stendra). 

  • Lifestyle changes can also improve your cardiovascular health and well being.

If you’d prefer to go the smart and safe route, we offer several erectile dysfunction medications online, following a consultation with a licensed healthcare provider who will determine if a prescription is appropriate.

Interested in learning more about dealing with ED? Our detailed guide to the treatment options for erectile dysfunction shares more about how you can improve your erections and have better sex, from medication to psychotherapy, pelvic floor exercises and other approaches. 

Give your penis the best and the safest — skip the supplements and try medication and other FDA-approved treatments today.

10 Sources

  1. Luiking, Y.C., Engelen, M.P. & Deutz, N.E. (2010, January). Regulation of Nitric Oxide Production in Health and Disease. 13 (1), 97-104. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2953417/
  2. Cartledge, J., Minhas, S. & Eardley, I. (2001, January). The role of nitric oxide in penile erection. Expert Opinion on Pharmacotherapy. 2 (1), 95-107. Retrieved from https://pubmed.ncbi.nlm.nih.gov/11336572/
  3. Burnett, A.L. (2004). Novel nitric oxide signaling mechanisms regulate the erectile response. International Journal of Impotence Research. 16, S15-S19. Retrieved from https://www.nature.com/articles/3901209
  4. Nassem, K.M. (2005). The role of nitric oxide in cardiovascular diseases. Molecular Aspects of Medicine. 26 (1-2), 33-65. Retrieved from https://pubmed.ncbi.nlm.nih.gov/15722114/
  5. Morita, M., et al. (2014, November). Oral supplementation with a combination of l-citrulline and l-arginine rapidly increases plasma l-arginine concentration and enhances NO bioavailability. Biochemical and Biophysical Research Communications. 454 (1), 53-57. Retrieved from https://www.sciencedirect.com/science/article/pii/S0006291X14018178
  6. Bescós, R., Sureda, A., Tur, J.A. & Pons, A. (2012, February 1). The effect of nitric-oxide-related supplements on human performance. Sports Medicine. 42 (2), 99-117. Retrieved from https://pubmed.ncbi.nlm.nih.gov/22260513/
  7. Cormio, L., De Siati, M., Lorusso, F., Selvaggio, O., Mirabella, L., Sanguedolce, F., & Carrieri, G. (2011). Oral L-citrulline supplementation improves erection hardness in men with mild erectile dysfunction. Urology, 77(1), 119–122. https://doi.org/10.1016/j.urology.2010.08.028
  8. Stanislavov, R. & Nikolova, V. (2003). Treatment of erectile dysfunction with pycnogenol and L-arginine. Journal of Sex & Marital Therapy. 29 (3), 207-213. Retrieved from https://pubmed.ncbi.nlm.nih.gov/12851125/
  9. Dhaliwal, A. & Gupta, M. (2021, June 25). PDE5 Inhibitors. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK549843/
  10. Treatment for Erectile Dysfunction. (2017, July). Retrieved from https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/treatment
Editorial Standards

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Kelly Brown MD, MBA
Kelly Brown MD, MBA

Dr. Kelly Brown is a board certified Urologist and fellowship trained in Andrology. She is an accomplished men’s health expert with a robust background in healthcare innovation, clinical medicine, and academic research. Dr. Brown is a founding member of Posterity Health where she is Medical Director and leads strategy and design of their Digital Health Platform, an innovative education and telehealth model for delivering expert male fertility care.

She completed her undergraduate studies at University of North Carolina at Chapel Hill (go Heels!) with a Bachelor of Science in Radiologic Science and a Minor in Chemistry. She took a position at University of California Los Angeles as a radiologic technologist in the department of Interventional Cardiology, further solidifying her passion for medicine. She also pursued the unique opportunity to lead departmental design and operational development at the Ronald Reagan UCLA Medical Center, sparking her passion for the business of healthcare.

Dr. Brown then went on to obtain her doctorate in medicine from the prestigious Northwestern University - Feinberg School of Medicine and Masters in Business Administration from Northwestern University - Kellogg School of Management, with a concentration in Healthcare Management. During her surgical residency in Urology at University of California San Francisco, she utilized her research year to focus on innovations in telemedicine and then served as chief resident with significant contributions to clinical quality improvement. Dr. Brown then completed her Andrology Fellowship at Medical College of Wisconsin, furthering her expertise in male fertility, microsurgery, and sexual function.

Her dedication to caring for patients with compassion, understanding, as well as a unique ability to make guys instantly comfortable discussing anything from sex to sperm makes her a renowned clinician. In addition, her passion for innovation in healthcare combined with her business acumen makes her a formidable leader in the field of men’s health.

Dr. Brown is an avid adventurer; summiting Mount Kilimanjaro in Tanzania (twice!) and hiking the incredible Torres del Paine Trek in Patagonia, Chile. She deeply appreciates new challenges and diverse cultures on her travels. She lives in Denver with her husband, two children, and beloved Bernese Mountain Dog. You can find Dr. Brown on LinkedIn for more information.

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