Should You Try L-Arginine for Erectile Dysfunction?

Key Points

• Erectile dysfunction is often a result of restricted blood flow to the penis. Some research suggests supplements for circulation may help improve erectile function.
• One of the most popular blood flow supplements is L-arginine, one of 20 amino acids the body needs to produce proteins and other essentials.
• Speak with your doctor to learn more about the right treatment combination for you.

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Anyone who is experiencing erectile dysfunction (ED) may feel overwhelmed by the various treatment options.

Defined as the persistent inability to get or maintain an erection satisfactory for sex, ED is common—especially for older men—and the demand for solutions is high. Prescription medications and medical devices present viable options to treat the condition. Beyond those, the market is awash with supplements purported to help.

One of the most common supplements is L-arginine, one of the 20 amino acids (AA) the body needs to function. As is the case with any supplement, keep in mind they are not regulated by the U.S. Food and Drug Administration (FDA) and may interact with any prescription drugs you might be taking.

What does L-arginine do sexually?

A medical condition that restricts blood flow to the penis, such as diabetes or heart disease, often causes erectile dysfunction. Treating the root cause can improve sexual and overall health. Medications and supplements such as L-arginine are vasodilators—they expand the blood vessels—and may help restore erections.

"One of nine essential amino acids, L-arginine isn't produced in the body and must be obtained from food or supplements," said David Shusterman, M.D., the CEO at NY Urology in New York City. "Most people get enough from their diet, but there are exceptions."

Besides being a building block for proteins, L-arginine produces a gas called nitric oxide (NO), said Scott Miller, M.D., the medical director at Wellstar Urology in Alpharetta, Georgia.

"Nitric oxide helps relax and open blood vessels, enabling more oxygen-rich blood to reach the organs and muscles, including the penis, making it crucial for erections," he said.

Nitric oxide is a gas, so the body breaks it down quickly.

"That's why having sufficient L-arginine is necessary to keep levels up," Shusterman said.

Research on L-arginine for ED suggests that capsules, powders and topical creams are generally safe and well-tolerated but ineffective. There are some exceptions.

How much L-arginine do you need?

"The appropriate dosage of L-arginine for improving sexual function varies," said Laurence Levine, M.D., a urologist and professor at Rush University in Chicago.

Studies have used a range of L-arginine dosages, but most suggest taking 2 to 3 grams daily.

"Remember that it's probably only beneficial if you have an L-arginine deficiency. Otherwise, your body will discard the excess," Shusterman said. "For example, if you're a bodybuilder and you're using a lot of the L-arginine to rebuild and restore your muscles, then you can have some deficiency in other areas, such as when you try to get an erection."

You're more likely to have a deficiency if you use a lot of nitric oxide or are vegetarian or vegan. Meats such as chicken, pork loin and turkey are some of the richest sources of L-arginine. You can also get the amino acid from soybeans, pumpkin seeds, peanuts, lentils, chickpeas, dairy products, spirulina and some protein powders.

Additionally, like many supplements, it doesn't have an immediate effect—if any at all. Unlike ED pharmaceuticals, for example, there's no recommended L-arginine dosage before sex.

"Although nitric oxide blood levels will increase after a higher dose of L-arginine, there has been no convincing evidence supporting on-demand use—meaning taking this supplement just before intimacy," Miller said.

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How long does it take for L-arginine to work sexually?

It's easy to get confused about erectile dysfunction and its treatments, given the prevalence of misinformation and questionable claims. But remember one important takeaway: Aside from prescription medications and medical devices, most treatments don't produce fast results, if they work at all.

"The time it takes for L-arginine or other blood flow supplements to affect sexual health varies from a few weeks to several months," Levine said. "It's not a quick-fix solution and should be viewed as part of a longer-term approach to improving sexual health."

Shusterman noted that, generally, a month is a reasonable time frame for testing. If you haven't seen any improvements within that period, buying another bottle may not be worth it.

Is it potentially better to pair L-arginine with another supplement to help erectile dysfunction?

False or unverified claims about supplements are as abundant as myths about ED, and there's not much solid evidence to support the use of L-arginine for ED.

Some research suggests pairing L-arginine with other vitamins and nutraceuticals may have some merit. Those other supplements include Pycnogenol, vitamin D and Yohimbe. Some people refer to pairing L-arginine with other supplements as the "Holy Grail" supplement stack.

Pycnogenol

Pycnogenol is the trademark name for a supplement that contains an extract from the bark of a European pine tree that contains antioxidants.

"When used together, L-arginine and Pycnogenol may have a synergistic effect," Levine said.

"It's thought to enhance nitric oxide production, complementing L-arginine's role."

Like other supplements for circulation, it may improve blood flow to the penis, thereby improving sexual health, he added.

Forty men ages 25 to 45 who had confirmed organic erectile dysfunction participated in a 2010 study published in the Journal of Sex and Marital Therapy. For the first month, participants took L-arginine, and just 5 percent of participants achieved a "normal" erection. In the second month, combining the two supplements restored function in 80 percent of participants. After three months, 92.5 percent experienced a normal erection.

Researchers concluded that L-arginine and Pycnogenol benefits were significant enough to constitute an effective ED treatment. They also noted the pairing didn't produce side effects associated with ED medications.

Vitamin D

"Known as the 'sunshine vitamin,' D is essential for most bodily functions, including cardiovascular, bone and immune system health," Miller said.

It's also crucial for healthy erectile function and plays a role in managing weight and diabetes, two significant risk factors for ED.

Scientists have conducted extensive research on vitamin D's effects on various conditions, and several studies suggest it may independently impact erectile function.

One 2020 meta-analysis published in Nutrients found a significant association between ED severity and vitamin D levels, suggesting vitamin D deficiency may worsen ED symptoms.

In a 2016 study of men with type 2 diabetes, participants with low vitamin D levels were more likely to have ED than those without a deficiency. Men who didn't have enough vitamin D also had worse symptoms.

A separate 2016 analysis of 3,390 men produced similar results.

"There's less evidence of its effectiveness when combined with L-arginine, but it may potentiate its effects by supporting overall vascular health and blood flow," Levine said. "It may also help by regulating levels of sex hormones, such as testosterone."

Miller noted that taking a supplement won't provide additional benefits if you already have enough vitamin D in your system.

"Unfortunately, vitamin D deficiency is very common, so many people would benefit from supplementation," he added.

The sun is the primary source of vitamin D, but you can also get it from fortified foods, such as milk and cereal, and fatty fish like salmon and mackerel, according to Mayo Clinic.

Vitamin D's effects aren't immediate, so if you are deficient, you may need to increase your intake for several weeks before you notice marked improvements.

Yohimbe

Yohimbe is an extract from the bark of an African evergreen tree and is a staple in traditional African medicine.

"People in the U.S. and other Western countries have also used it to treat ED for decades," Miller said.

Some research suggests it works by blocking alpha-2 adrenergic receptors, which can inhibit erections, according to a 2000 study. It may also increase nitric oxide levels, a 2014 report suggested.

"However, evidence for its effectiveness is less than convincing," Miller said. "As for combining it with other supplements, such as L-arginine and Pycnogenol, the jury is still out."

Combining Yohimbe with L-arginine helped somewhat with mild to moderate ED but wasn't effective for severe dysfunction, a 2010 study suggested.

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Is it safe to take Pycnogenol and L-arginine together?

"It's generally safe to take Pycnogenol and L-arginine for ED," Shusterman said.

He noted some potential risks and contraindications, stressing that both supplements can lower blood pressure. Doctors advise against taking them in combination with blood pressure medications or prescription drugs for erectile dysfunction.

Additionally, L-arginine can lower blood sugar, so it may be inadvisable for people taking diabetes medications, according to Mayo Clinic. Moreover, experts recommend avoiding L-arginine if you've recently had a heart attack or are taking water pills, diabetes medications or blood thinners.

Having too much L-arginine could also potentially trigger the virus that causes cold sores and genital herpes, so exercise caution if you have these conditions.

Are there too many amino acid side effects?

Taking too much L-arginine isn't likely to cause any serious issues for most people. However, both Levine and Miller suggested that it may cause gastrointestinal problems, bloating, abdominal cramping, headache or lower blood pressure.

Additionally, excessive amino acid intake can disrupt the body's nutrient balance, Levine said. For example, excessive protein may affect kidney function in people susceptible to problems.

The bottom line

If you have ED or are concerned about your partner not getting erect, you may consider blood flow supplements or medications as a potential treatment.

"Some of these, such as L-arginine and Pycnogenol, have more promise than others. Still, there's little evidence of their effectiveness, particularly for people with more advanced ED," Levine said.

Before taking L-arginine for ED—or any other supplement—talk to your doctor to ensure it's safe, Shusterman said. Consulting with a professional is also essential to rule out, diagnose or manage any underlying conditions that could cause ED and jeopardize your health.