L-Arginine for ED: Effectiveness, Dosage & More (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.

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®.

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.

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:

• Sildenafil citrate (generic for Viagra)

• Tadalafil (generic for Cialis)

• Avanafil (sold as for Stendra®)

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.

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.