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How Long Does It Take for L-Citrulline to Work for ED?

Angela Sheddan

Reviewed by Angela Sheddan, FNP

Written by Rachel Sacks

Published 06/02/2023

How long does it take for L-citrulline to work for ED? We’re here to break it down for you.

With erectile dysfunction (ED) being an incredibly common health condition for many men (around 30 million are affected), the number of treatments available is vast. From oral medications to natural treatments for ED, it can be difficult to know which is best.

One alternative treatment for erectile dysfunction you may have heard of is L-citrulline supplements. An amino acid produced by the body, L-citrulline is converted to L-arginine, another type of amino acid. Some people take L-citrulline supplements to produce L-arginine, which improves blood flow by creating nitric oxide, a gas that helps widen blood vessels.

Some people may use L-citrulline supplementation or L-citrulline malate (one of the forms of citrulline, a combination of L-citrulline with malic acid) for exercise performance to improve muscle strength or reduce muscle soreness after a tough workout.

Others may use L-citrulline for ED.

But are there L-citrulline benefits for ED? And if so, how long does it take for L-citrulline to work for ED?

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L-Citrulline for ED: The Research

What does L-citrulline do, exactly, and is supplemental citrulline an effective treatment for erectile dysfunction?

As we mentioned above, L-citrulline converts to L-arginine, which increases nitric oxide production to widen blood vessels. Healthy blood flow is an important part of how erections work, so in theory, L-citrulline could help reduce ED.

To understand how L-citrulline might help reduce ED, let’s get into the process of erections. When you feel sexually aroused, your nervous system sends a signal to the tissue inside your penis, referred to as the corpora cavernosa.

The blood vessels that supply blood to your penis dilate, increasing blood flow and creating an erection.

One molecule involved in this process is nitric oxide, which plays a key role in relaxing the smooth muscle tissue that controls blood flow to the erectile tissue inside your penis.

L-citrulline converts to L-arginine, which helps nitric oxide production. However, arginine supplementation (or even nitric oxide supplements) may not be the most efficient way to produce nitric oxide — which is why people may use L-citrulline supplements to increase arginine levels and produce a normal erection.

You may see L-arginine marketed as a natural remedy for erectile dysfunction, but there isn’t much evidence to support this claim.

Similarly, the current research on L-citrulline for ED is also very limited.

One small study of 24 men with moderate or mild erectile dysfunction found that oral citrulline supplementation was an effective treatment in improving erection hardness scores and overall sexual satisfaction.

Another small study of 13 men also found that oral L-citrulline supplementation was effective in treating ED. This treatment, however, was a combination of citrulline supplementation with a polyphenol known as resveratrol and a PDE5 inhibitor, the first line of treatment for most men with ED.

Though research on the effectiveness of L-citrulline for ED is limited, this dietary supplement is believed to be safe. Still, there haven’t been any large randomized clinical trials to assess the safety of L-citrulline for ED treatment.

There are proven treatments for ED (which we’ll cover below), but some men may prefer to try L-citrulline when usual ED medications don’t work for them or if they experience too many side effects.

But how long does it take for L-citrulline to work for ED? Keep reading to find out.

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How Long Does It Take for L-Citrulline to Work for ED?

Since there hasn’t been a large study to assess the effects of L-citrulline on ED, the answer to “How long does it take for L-citrulline to work for ED?” isn’t clear.

The duration of treatment for both studies we mentioned above was two months, with patients taking a placebo (an inactive drug) for one month, followed by another month of oral citrulline supplementation.

More research would be needed to fully understand not only how long L-citrulline takes to work for erectile dysfunction but also whether oral citrulline supplementation is effective.

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L-Citrulline Dosage for ED

The exact L-citrulline dosage for ED is also unclear, once again due to the limited amount of studies.

In the first study on oral L-citrulline supplementation we mentioned, patients received a dosage of 1.5 grams of citrulline each day for a month. Meanwhile, the second study saw patients receive 800 milligrams of L-citrulline along with 300 milligrams of transresveratrol each day.

One source recommends an L-citrulline dosage of 2,000 milligrams three times a day or 1.76 grams of citrulline malate for every 1 gram of citrulline you might take for circulatory health. However, there isn’t much research to support this dosage.

L-Citrulline Side Effects

Citrulline has been used as an oral supplement for many years without reports of serious safety concerns.

A review of citrulline malate supplements found only a couple of mild L-citrulline side effects were experienced:

  • Nausea

  • Diarrhea

If you want to take oral L-citrulline supplements for ED, consult with a healthcare provider first.

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In Summary: L-Citrulline for ED

Erectile dysfunction is the inability to attain and maintain an erection sufficient for sexual satisfaction, and it affects many men. Fortunately, there are several treatment options — even natural remedies like L-citrulline.

An amino acid produced by the body, L-citrulline may help create more nitric oxide, which, in turn, helps promote healthy blood flow. Increased blood flow is one part of the process of getting an erection. So many people may turn to L-citrulline supplements to increase blood flow and reduce ED.

The research on L-citrulline for ED is light, though. And while this supplement doesn’t appear to have adverse effects, there are many other proven treatments for erectile dysfunction to consider.

One of the most common treatments is an oral medication known as PDE5 inhibitors. These work by relaxing the arteries and increasing blood flow to your penis to improve erectile function.

The most common PDE5 inhibitors are sildenafil (the active ingredient in Viagra®), tadalafil (Cialis®), vardenafil (Levitra) and avanafil (Stendra®). They’re available as either oral medication or chewable mints.

While a natural treatment like L-citrulline may sound more appealing, these medications have plenty of research to support their effectiveness. If you’re concerned about possible side effects of medications or drug interactions, talk to your healthcare provider to answer any questions.

Explore ED treatments available online from Hims today.

12 Sources

  1. Definition & Facts for Erectile Dysfunction - NIDDK. (n.d.). National Institute of Diabetes and Digestive and Kidney Diseases. Retrieved from https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/definition-facts
  2. Allerton, T. D., Proctor, D. N., Stephens, J. M., Dugas, T. R., Spielmann, G., & Irving, B. A. (2018). L-Citrulline Supplementation: Impact on Cardiometabolic Health. Nutrients, 10(7). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6073798/
  3. Gough, L. A., Sparks, S. A., McNaughton, L. R., Higgins, M. F., Newbury, J. W., Trexler, E., Faghy, M. A., & Bridge, C. A. (2020). A critical review of citrulline malate supplementation and exercise performance. European Journal of Applied Physiology, 121(12), 3283-3295. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8571142/
  4. Panchatsharam, P.K., Durland, J. & Zito, P.M. (2022, May 8). Physiology, Erection. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK513278/
  5. Davies, K. P. (2015). Development and therapeutic applications of nitric oxide releasing materials to treat erectile dysfunction. Future Science OA, 1(1). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4806684/
  6. Dietary Supplements for Exercise and Athletic Performance - Health Professional Fact Sheet. (n.d.). NIH Office of Dietary Supplements. Retrieved from https://ods.od.nih.gov/factsheets/ExerciseAndAthleticPerformance-HealthProfessional/#citrulline
  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. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S0090429510016614
  8. Shirai, M., Hiramatsu, I., Aoki, Y., Shimoyama, H., Mizuno, T., Nozaki, T., Fukuhara, S., Iwasa, A., Kageyama, S., & Tsujimura, A. (2018). Oral L-citrulline and Transresveratrol Supplementation Improves Erectile Function in Men With Phosphodiesterase 5 Inhibitors: A Randomized, Double-Blind, Placebo-Controlled Crossover Pilot Study. Sexual Medicine, 6(4), 291-296. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6302103/
  9. Neri, L., & Woznik, P. (n.d.). Citrulline — Health benefits, dosage, safety, side-effects, and more | Supplements. Examine. Retrieved from https://examine.com/supplements/citrulline/
  10. Johnson, S. (2017, November 20). L-Citrulline. FDA.report. Retrieved from https://fda.report/media/109619/FDA-Presentations-for-the-November-20-21--2017-Meeting-of-the-Pharmacy-Compounding-Advisory-Committee.pdf
  11. Gough, L.A., Sparks, S.A., McNaughton, L.R. et al. (2021). A critical review of citrulline malate supplementation and exercise performance. Eur J Appl Physiol, 121, 3283–3295. Retrieved from https://link.springer.com/article/10.1007/s00421-021-04774-6
  12. Dhaliwal, A. & Gupta, M. (2022, May 20). PDE5 Inhibitors. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK549843/
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.

Angela Sheddan, FNP

Dr. Angela Sheddan has been a Family Nurse Practitioner since 2005, practicing in community, urgent and retail health capacities. She has also worked in an operational capacity as an educator for clinical operations for retail clinics. 

She received her undergraduate degree from the University of Tennessee at Chattanooga, her master’s from the University of Tennessee Health Science Center in Memphis, and her Doctor of Nursing Practice from the University of Alabama in Tuscaloosa. You can find Angela on LinkedIn for more information.


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