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L-Arginine for ED: Effectiveness, Dosage & More

Mike Bohl, MD, MPH, ALM

Reviewed by Mike Bohl, MD

Written by Geoffrey C. Whittaker

Published 09/17/2017

Updated 01/14/2024

Chances are, if you think you have erectile dysfunction (ED), you’ve already looked into dietary supplements — and pretty much any option other than seeing a healthcare professional.

We get it. Talking about ED with a white-coated urology expert sounds pretty awkward. And if an alternative solution is grabbing a bottle of capsules off the local supplement store shelf, why not start there with something like l-arginine?

For those who don’t know, l-arginine is an amino acid. It’s often promoted online as a "natural treatment" for hypertension (high blood pressure), peripheral arterial disease (PAD) and angina. Some even claim that its vasodilation effects — the same ones that allegedly improve your blood pressure — can help with erectile dysfunction.

Below, we’ll explain more about what l-arginine is, why it might help with ED and other benefits this amino acid may offer. We’ll also contextualize this info in the big picture of ED treatment and suggest some safer, proven options for those of you who aren’t already in the check-out line of a GNC.

Let’s get started.

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L-arginine is an amino acid your body uses to create proteins, glutamate, creatine, proline, urea, polyamines and nitric oxide. It’s found naturally in fish, poultry, red meat and dairy products.

While most people get the l-arginine they need from food, it’s also sold as a dietary supplement.

In supplement form, natural health websites often position this product with more “aspirational” claims. According to the internet, l-arginine is a natural alternative to prescription ED medications like Viagra® and Cialis®. 

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Studies on the effects of l-arginine as an ED supplement are mixed — and as of right now, there aren’t very many of them.

An overall lack of data makes confirming the supposed benefits hard for experts. There aren’t enough systematic reviews of double-blind or placebo-controlled trials to confidently say if or how l-arginine can help with ED. The modest information we do have comes from smaller studies.

Erections are all about blood flow through the blood vessels to the erectile tissues. One claim is that l-arginine helps synthesize nitric oxide, which plays a key role in relaxing smooth muscle tissue in the arteries and controlling blood flow to erectile tissue. Nitric oxide is produced within the body from l-arginine by a family of enzymes called nitric oxide synthases.

Still, scientific data on supplemental l-arginine’s ability to  impact ED is mixed at best.

Current Research on L-Arginine for Erectile Dysfunction

A 1999 study did not find a difference between l-arginine and placebo in men with mixed-type erectile dysfunction.

A 2003 study found that arginyl aspartate and Pycnogenol® (a natural health supplement made from pine bark extract) improved sexual function in men with erectile dysfunction after several months.

More recently, a 2019 review — which included studies with positive results, on the International Index of Erectile Function (IIEF) — noted positive evidence for the efficacy of l-arginine. But it concluded that additional research with larger sample sizes is needed to find out more about l-arginine’s potential role in treating erectile dysfunction.

L-arginine supplements are often marketed as physical performance boosters that can affect endothelial cells to increase blood flow and improve vascular function. But, as with many other supplements, not all supposed benefits of l-arginine are backed up by real scientific evidence. 

Studies have found that l-arginine may offer benefits for a diverse range of conditions, including:

  • Hypertension

  • Peripheral artery disease

  • Angina

Keep scrolling to learn about this amino acid’s potential benefits for sexual function.

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As for l-arginine’s non-erectile sexual benefits, the information is far more slim. Anecdotal internet reports of guys with moderate ED seeing more stamina and improved erectile function haven’t been corroborated by experiments.

Before you start popping these things like they’re Flintstones vitamins, just remember: A high-dose intake of l-arginine has never been directly associated with better results on athletic performance, endocrine function (which matters for testosterone levels) or anything similar.

L-arginine also stimulates the release of several critical chemical compounds within the body, including growth hormone and insulin. Its effects on blood flow may help improve some aspects of physical performance — and, in theory, this could lead to better sexual performance…indirectly…eventually.

However, it’s important to note that other studies on l-arginine largely don’t show the same level of improvement in athletic performance or recovery.

Does L-Arginine Increase Size?

Although l-arginine’s effects on blood flow might help you to get and maintain an erection, it’s unclear whether supplements containing L-arginine offer any benefits for penis size, sex drive or sexual performance.

Currently, the only reliable way to increase penis size is through surgery — and this comes with some serious downsides, from temporary pain and discomfort to a risk of real changes in the function of your penis.

The good news is that you probably don’t need to worry about your penis size — at least, not as much as you think. Our guide to average penis size explains why most guys are fine when it comes to measurements below the belt, especially in terms of partner satisfaction.

Since l-arginine isn’t an FDA-approved medication for ED, clinical trials haven’t determined the most effective dosage or the safest dosage for ED, so we can’t give you specific numbers.

You might be wondering how long it takes l-arginine to work sexually, and the answer is unclear. It could take several months to see results, but this isn’t really backed by any concrete evidence.

If you’re considering using L-arginine, make sure to follow the usage instructions provided with the supplement. And don’t exceed the recommended dosage listed on the label.

Like other dietary supplements (and prescription medications), l-arginine can potentially cause side effects. Known side effects of l-arginine include:

  • Bloating

  • Diarrhea

  • Low blood pressure

  • Pain in the abdominals

  • Allergic reactions

L-arginine supplements may interact with certain over-the-counter and prescription medications, including those used to treat diabetes and cardiovascular disease.

Medications that could interact with l-arginine include: 

  • Isoproterenol

  • Diabetes medications

  • ACE (angiotensin-converting enzyme) inhibitors

  • Angiotensin receptor blockers (ARBs)

  • Antihypertensive medications

  • Antiplatelet and anticoagulant medications

  • Testosterone

  • Potassium-sparing diuretics

L-arginine may also interact with medications for erectile dysfunction, such as sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra®) and avanafil (Stendra®).

Let your healthcare provider know about any medications you currently take or have recently used before starting l-arginine supplementation.

Currently, the most effective treatments for ED are prescription PDE5 inhibitors, which work by relaxing the arteries that supply blood to the penis. 

PDE5 inhibitors prescribed to treat ED include:

There are also other types of medication for ED, such as the injectable, alprostadil.

Besides taking medication, making simple changes to your habits and lifestyle may help improve your erections and prevent many common forms of sexual dysfunction.

Eating a healthy diet, exercising for cardiovascular health and other good habits can help you avoid erectile dysfunction — not to mention heart attacks, type 2 diabetes and obesity, all of which are risk factors for ED itself.

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If you’re reading this hoping for some definitive proof that l-arginine improves sexual function, we’re sorry to disappoint. Conclusive meta-analyses, randomized controlled trials and other sexual medicine research into the effectiveness of oral l-arginine supplements for ED just aren’t there yet.

Here’s what we know:

  • L-arginine is converted into nitric oxide, which helps dilate blood vessels, which — in theory — may have some effect on blood flow to the penis.

  • But, medications like phosphodiesterase type 5 inhibitors and other FDA-approved medications for ED have better understood safety and efficacy.

  • It’s best to proceed with caution before using any combination of l-arginine with other supplement ingredients like l-citrulline or yohimbine — or anything you can get in the supplement aisle.

  • Treatment of erectile dysfunction should be safe, effective and reliable. And right now, lL-arginine isn’t, necessarily

  • The etiology (causes) of ED are more complicated and diverse than “one supplement to fix it all.” This means your best option for treatment is to visit a healthcare professional for a diagnosis and management plan.

Ready to do something about it? Skip the supplements for now, and talk to a medical professional through our online sexual health platform.

10 Sources

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  2. U.S. National Library of Medicine. (n.d.-d). L-arginine: Medlineplus supplements. MedlinePlus. https://medlineplus.gov/druginfo/natural/875.html.
  3. Gad, M. Z. (2010). Anti-aging effects of l-arginine. Journal of Advanced Research, 1(3), 169-177. https://www.sciencedirect.com/science/article/pii/S2090123210000573.
  4. Pahlavani N, Entezari MH, Nasiri M, et al. The effect of l-arginine supplementation on body composition and performance in male athletes: a double-blinded randomized clinical trial. European Journal of Clinical Nutrition. 2017 Apr;71(4):544-548. https://europepmc.org/article/med/28120856.
  5. Stanislavov, R., & Nikolova, V. (2003). Treatment of erectile dysfunction with pycnogenol and L-arginine. Journal of sex & marital therapy, 29(3), 207–213. https://pubmed.ncbi.nlm.nih.gov/12851125/.
  6. Brooks, J. R., Oketch-Rabah, H., Low Dog, T., Gorecki, D. K., Barrett, M. L., Cantilena, L., Chung, M., Costello, R. B., Dwyer, J., Hardy, M. L., Jordan, S. A., Maughan, R. J., Marles, R. J., Osterberg, R. E., Rodda, B. E., Wolfe, R. R., Zuniga, J. M., Valerio, L. G., Jr, Jones, D., Deuster, P., … Sarma, N. D. (2016). Safety and performance benefits of arginine supplements for military personnel: a systematic review. Nutrition reviews, 74(11), 708–721. https://academic.oup.com/nutritionreviews/article/74/11/708/2281654?login=false.
  7. Davies K. P. (2015). Development and therapeutic applications of nitric oxide releasing materials to treat erectile dysfunction. Future science OA, 1(1), FSO53. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4806684/.
  8. Koolwal, A., J., M., Sathyanarayana Rao, T. S., & Koolwal, G. D. (2019). L-arginine and Erectile Dysfunction. Journal of Psychosexual Health. https://journals.sagepub.com/doi/10.1177/2631831818822018.
  9. Panchatsharam PK, Durland J, Zito PM. Physiology, Erection. [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK513278/.
  10. Klotz, T., Mathers, M. J., Braun, M., Bloch, W., & Engelmann, U. (1999). Effectiveness of oral L-arginine in first-line treatment of erectile dysfunction in a controlled crossover study. Urologia internationalis, 63(4), 220–223. https://pubmed.ncbi.nlm.nih.gov/10743698/.
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.

Mike Bohl, MD

Dr. Mike Bohl is a licensed physician, a Medical Advisor at Hims & Hers, and the Director of Scientific & Medical Content at a stealth biotech startup, where he is involved in pharmaceutical drug development. Prior to joining Hims & Hers, Dr. Bohl spent several years working in digital health, focusing on patient education. He has also worked in medical journalism for The Dr. Oz Show (receiving recognition for contributions from the National Academy of Television Arts and Sciences when the show won Outstanding Informative Talk Show at the 2016–2017 Daytime Emmy® Awards) and at Sharecare. He is a Medical Expert Board Member at Eat This, Not That! and a Board Member at International Veterinary Outreach.

Dr. Bohl obtained his Bachelor of Arts and Doctor of Medicine from Brown University, his Master of Public Health from Columbia University, and his Master of Liberal Arts in Extension Studies—Journalism from Harvard University. He is currently pursuing a Master of Business Administration and Master of Science in Healthcare Leadership at Cornell University. Dr. Bohl trained in internal medicine with a focus on community health at NYU Langone Health.

Dr. Bohl is Certified in Public Health by the National Board of Public Health Examiners, Medical Writer Certified by the American Medical Writers Association, a certified Editor in the Life Sciences by the Board of Editors in the Life Sciences, a Certified Personal Trainer and Certified Nutrition Coach by the National Academy of Sports Medicine, and a Board Certified Medical Affairs Specialist by the Accreditation Council for Medical Affairs. He has graduate certificates in Digital Storytelling and Marketing Management & Digital Strategy from Harvard Extension School and certificates in Business Law and Corporate Governance from Cornell Law School.

In addition to his written work, Dr. Bohl has experience creating medical segments for radio and producing patient education videos. He has also spent time conducting orthopedic and biomaterial research at Case Western Reserve University and University Hospitals of Cleveland and practicing clinically as a general practitioner on international medical aid projects with Medical Ministry International.

Dr. Bohl lives in Manhattan and enjoys biking, resistance training, sailing, scuba diving, skiing, tennis, and traveling. You can find Dr. Bohl on LinkedIn for more information.

Publications

  • Younesi, M., Knapik, D. M., Cumsky, J., Donmez, B. O., He, P., Islam, A., Learn, G., McClellan, P., Bohl, M., Gillespie, R. J., & Akkus, O. (2017). Effects of PDGF-BB delivery from heparinized collagen sutures on the healing of lacerated chicken flexor tendon in vivo. Acta biomaterialia, 63, 200–209. https://www.sciencedirect.com/science/article/abs/pii/S1742706117305652?via%3Dihub

  • Gebhart, J. J., Weinberg, D. S., Bohl, M. S., & Liu, R. W. (2016). Relationship between pelvic incidence and osteoarthritis of the hip. Bone & joint research, 5(2), 66–72. https://boneandjoint.org.uk/Article/10.1302/2046-3758.52.2000552

  • Gebhart, J. J., Bohl, M. S., Weinberg, D. S., Cooperman, D. R., & Liu, R. W. (2015). Pelvic Incidence and Acetabular Version in Slipped Capital Femoral Epiphysis. Journal of pediatric orthopedics, 35(6), 565–570. https://journals.lww.com/pedorthopaedics/abstract/2015/09000/pelvic_incidence_and_acetabular_version_in_slipped.5.aspx

  • Islam, A., Bohl, M. S., Tsai, A. G., Younesi, M., Gillespie, R., & Akkus, O. (2015). Biomechanical evaluation of a novel suturing scheme for grafting load-bearing collagen scaffolds for rotator cuff repair. Clinical biomechanics (Bristol, Avon), 30(7), 669–675. https://www.clinbiomech.com/article/S0268-0033(15)00143-6/fulltext

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