Nitric Oxide Supplements: Uses & How They Work

Vicky Davis

Medically reviewed by Vicky Davis, FNP

Written by Our Editorial Team

Last updated 5/23/2022

If you’ve ever researched natural treatments for erectile dysfunction, you’ve likely seen people mention nitric oxide supplements.

Nitric oxide, or NO, is a molecule that's produced naturally inside your body. It plays a key role in promoting blood flow throughout your vascular system, making it important for your physical function, including your ability to get and maintain an erection.

Available over the counter, many nitric oxide supplements claim to boost blood flow, giving you stronger erections and better physical performance. 

Below, we’ve explained what nitric oxide is, as well as the important functions it has within your body.

We’ve also looked at some of the science behind nitric oxide supplements to explain whether or not they’re worth using for better physical health and erections. 

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

What Does Nitric Oxide Do?

Nitric oxide is a gas that’s produced naturally by your body. Inside your body, it works as a type of signaling molecule for your cells and organs. Nitric oxide plays a role in almost every cellular and organ function in your body. 

The key role of nitric oxide 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, all while removing waste products.

Nitric oxide controls blood flow 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. 

Does Nitric Oxide Help Sexually?

One area of the body that’s affected by nitric oxide is your penis. 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.

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. 

Low nitric oxide levels may also contribute to a higher risk of common heart health issues, such as cardiovascular disease. 

What Are Nitric Oxide Supplements?

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 powdered drinks or capsules, and can be purchased from drug stores, health food stores and online. 

However, there’s a bit of a catch to these products. 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 increase its own nitric oxide production. 

More specifically, most nitric oxide boosters contain the active ingredients L-arginine, L-citrulline, or a combination of the two. 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. However, like with lots of dietary supplements, many of the studies used to support the idea that taking nitric oxide precursors boosts nitric oxide production relies on animal research, not studies involving humans.

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

While this type of research is definitely promising, it doesn’t necessarily mean that supplements for nitric oxide work the same way in humans.

However, there is some higher-quality evidence that suggests that nitric oxide supplements may offer benefits for health and wellbeing. 

For example, a review published in the journal Sports Medicine found that nitric oxide donors (a term for substances that are used to produce nitric oxide, such as L-arginine and L-citrulline) 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.

In short, nitric oxide supplements contain ingredients that your body can use to increase its own nitric oxide production. While they do appear to have benefits, their effects on nitric oxide levels within your body aren’t completely clear.

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Do Nitric Oxide Supplements Help With ED?

Many nitric oxide supplements are marketed as over-the-counter products for improving sexual health and promoting stronger erections

As dietary supplements rather than medications, there aren’t any nitric oxide supplements that have been approved by the FDA to treat erectile dysfunction. This means that it’s unlikely your primary care provider will ever recommend them as treatment options.

Although nitric oxide supplements shouldn’t be viewed as treatments for ED, a small amount of research suggests that they may have benefits for erections and male sexual function. 

For example, an article published in the journal Future Science OA looked at several studies of supplements containing L-arginine and L-citrulline, noting that some had shown improvements in Erection Hardness Score (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.

Put simply, there’s some evidence that L-arginine and L-citrulline supplements may contribute to more consistent erections and sexual performance. 

However, most studies of nitric oxide supplements for sexual performance are small in size, with most involving less than 50 men in total. This means that although they’re interesting, it’s difficult to draw any firm conclusions from their findings. 

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Evidence-Based Treatments for Erectile Dysfunction

If you have erectile dysfunction, using a nitric oxide booster supplement might help to improve blood flow and give you more consistent erections. 

However, you’ll likely get better results by using an evidence-based, FDA-approved medication for erectile dysfunction.

Currently, the FDA has approved four medications for erectile dysfunction: sildenafil (the active ingredient in Viagra), tadalafil (Cialis®), vardenafil (Levitra®) and avanafil (Stendra®). 

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.

These medications can be taken as-needed 30 to 60 minutes before sex, making it easy to deal with ED and improve your sexual performance.

We offer several erectile dysfunction medications online, following a consultation with a licensed healthcare provider who will determine if a prescription is appropriate.

You can also reduce your risk of dealing with erectile dysfunction by making healthy changes to your habits and lifestyle. 

For example, if you’re physically inactive, exercising frequently and maintaining a healthy weight may help improve your sexual function and prevent ED from occurring. Limiting your alcohol intake, quitting smoking and avoiding illicit drugs can also contribute to better erections.

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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Access Help for ED Online

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.

Although research on nitric oxide supplements and ED is limited, some research suggests that ingredients such as L-arginine and L-citrulline, which can be found in nitric oxide supplements, may help to improve erections and treat ED.

Using a nitric oxide supplement may help to strengthen your erections and improve your sexual function. However, if you have erectile dysfunction, you’ll notice the biggest improvements from evidence-based medications like sildenafil (Viagra), tadalafil (Cialis) and avanafil (Stendra). 

We offer these 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. 

10 Sources

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.

  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
  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
  3. Burnett, A.L. (2004). Novel nitric oxide signaling mechanisms regulate the erectile response. International Journal of Impotence Research. 16, S15-S19. Retrieved from
  4. Nassem, K.M. (2005). The role of nitric oxide in cardiovascular diseases. Molecular Aspects of Medicine. 26 (1-2), 33-65. Retrieved from
  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
  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
  7. Davies, K.P. (2015, August). Development and therapeutic applications of nitric oxide releasing materials to treat erectile dysfunction. Future Science OA. 1 (1), FSO53. Retrieved from
  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
  9. Dhaliwal, A. & Gupta, M. (2021, June 25). PDE5 Inhibitors. StatPearls. Retrieved from
  10. Treatment for Erectile Dysfunction. (2017, July). Retrieved from

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.