How Long Does It Take for L-Arginine To Work Sexually

If you’re one of the estimated 30 to 50 million men in the United States dealing with erectile dysfunction (ED), you’re probably also among the many guys looking for a solution on the local supplement store shelf.

If so, you’ve probably seen l-arginine, a supplement sold as a way to help treat ED. So then you may wonder, how long does it take for l-arginine to work sexually? And does it really help at all?

Below, we’ll explain more about what l-arginine is, why it might help with ED, and how it might offer  other health benefits. We’ll also look at how l-arginine may fit into a broader treatment of ED and suggest some safer, proven options for those of you who aren’t already in the check-out line of your neighborhood GNC.

Let’s get started.

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

L-arginine is 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. Vasodilation refers to the widening of your arteries and veins to improve blood flow.

While most people get all 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. L-arginine is often touted as a natural alternative to prescription ED medications like Viagra^® and Cialis^®. 

L-arginine is similar to another amino acid sold as a nitric oxide supplement for ED. Like l-arginine, l-citrulline is marketed as a natural solution to ED without a ton of data to definitively back up those claims.

There have been just a handful of studies on the effects of l-arginine as an ED supplement. And the published studies have produced mixed results.  

This general 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 well 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 in the penis. One claim is that since 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, supplementation of l-arginine would lead to more blood flow to the penis. Nitric oxide is produced within the body from l-arginine by a family of enzymes called nitric oxide synthases.

The best time to take l-arginine for ED depends on several factors, including your metabolism, when you plan to begin sexual activity, and if you are also taking other ED medications. Though there may be no “best” time, a 2019 study suggests that l-arginine reaches its peak concentration in your bloodstream about half an hour after taking a supplement. 

Current Research on L-Arginine for Erectile Dysfunction

To be fair, there has been some encouraging research on l-arginine and ED — enough perhaps to consider trying the supplement or adding it to more proven ED treatments.

A 2024 study of nutriceuticals (supplements derived from food sources) to treat ED found that l-arginine appeared to be more useful in boosting erectile function compared with other supplements. The researchers also noted that l-arginine’s effects were most helpful when combining it with phosphodiesterase type 5 inhibitors, such as tadalafil (Cialis) and sildenafil (Viagra). 

A 2019 review of ten studies suggests that L-arginine may be beneficial in addressing erectile dysfunction at doses ranging from 1,500 to 5,000 mg. The researchers found notable improvements in mild to moderate ED when compared to a placebo. Participants also reported enhanced erectile function and greater sexual satisfaction.

However, a 1999 study did not find a difference between l-arginine and placebo in men with mixed-type 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 before you start popping these things like 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 may, however, help  stimulate 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.

Some research suggests that l-arginine may offer benefits for a number of health conditions, including hypertension. 

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 penis fillers, or surgery — and this can come 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.

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

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, we can’t give you specific numbers. The National Institutes of Health suggests that a daily dose of 2.5 to 5 grams of l-arginine may help with erectile dysfunction, especially when used with medications such as sildenafil and tadalafil. Again there are no major clinical trials to verify l-arginine’s effectiveness at any dose on its own.

You also  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 a lot of concrete evidence. 

A 2022 study did suggest, though, that high doses of l-arginine — 6 grams a day for three months — was associated with improved erectile function.

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. Before adding any supplements to your routine it’s always a good idea to consult your healthcare provider.

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

• Vomiting

• Nausea

• Bloating

• Diarrhea

• Stomach pain 

• Headache

• Heartburn  

• Palpitations

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

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 any of these medications or any supplements for ED, making simple changes to your habits and lifestyle may help improve your erections and prevent many common forms of sexual dysfunction.

For example, eat a healthy diet packed with vitamins and other nutrients that support good circulation and sexual health. Exercising for cardiovascular health, quitting smoking, limiting alcohol intake, and other good habits also 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 medical research into the effectiveness of oral l-arginine supplements for ED just aren’t there yet.

Here’s what we do 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, l-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.