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A complete guide to L-arginine for erections

By Ashton Sheriff | Medically reviewed by Dr Jon Eriksson
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L-arginine is a versatile little amino acid. Some of the supposed benefits of taking it include reduced blood pressure, relief from angina, and even increased output in the gym (although this last one is more likely to be founded in “broscience” than actual science). 

L-arginine is also believed to improve erectile function. In this complete guide to L-arginine for erections, we delve into the science behind L-arginine’s ability to improve erectile function and examine just how effective it is for treating erectile dysfunction. 

What is L-arginine?

L-arginine is a naturally-occurring amino acid that's produced in the body. It's also found in red meat, fish, poultry, and other protein-rich foods. For our vegan friends, L-arginine can be found in high-protein food sources such as soy, whole grains, and beans.   

It can be taken orally or topically (on the skin) and comes in the form of tablets, powders, capsules, creams, and gels. 

L-arginine benefits for erectile dysfunction

L-arginine plays an important role in producing nitric oxide (NO) - a key molecule involved in getting and maintaining erections

In a nutshell, NO is made from L-arginine by the action of nitric synthase enzymes. The reason why NO is such a big deal when it comes to getting erections is because it's a vasodilator - meaning it widens the blood vessels in your penis. 

Erections are essentially the result of increased blood flow to the penis. By widening blood vessels, NO allows more blood to enter the penis, which results in stronger, harder erections. 

This is the theory. But just how effective is L-arginine in treating erectile dysfunction?

Let’s find out. 

How effective is L-arginine?

Various studies have shown that L-arginine may be somewhat effective for treating erectile dysfunction. One fairly recent study showed that men with mild to moderate ED (who also had type 2 diabetes) reported improvements in their erections after being given an L-arginine dosage of 5000mg for four weeks. Another older study found that 31% of men reported an improvement in sexual function after being given L-arginine orally for 6 weeks. 

It’s worth noting that the studies on L-arginine for ED have been relatively small-scale so far, and this area of erectile dysfunction research could still benefit from further exploration. 

As always, it’s advisable to consult your doctor before taking L-arginine for ED (or any natural erectile dysfunction remedy) to ensure it’s safe and doesn’t conflict with any medication you’re currently taking.

Are there any L-arginine side effects?

L-Arginine is typically regarded as “safe”, but it can have some side effects. Potential L-arginine side effects include: 

  • Nausea.

  • Diarrhoea.

  • Abdominal pain.

  • Bloating.

  • Gout.

  • Allergic response.

  • Airway inflammation or worsening of asthma symptoms.

  • Increased risk of death if taken after a heart attack. 

  • Re-triggering of herpes virus (if you have had cold sores or genital herpes). 


L-Arginine may also adversely interact with some types of medication, such as: 

  • High blood pressure medication.

  • Erectile dysfunction medication. 

  • Anticoagulants and anti-platelet drugs. 

  • Diabetes drugs. 

  • Isoproterenol. 

  • Nitrates. 

  • Diuretics.

Once again, talk to your doctor before taking L-arginine to make sure it is safe for you to take and does not interact with any medication you’re currently taking. 

Are there any L-arginine foods?

The body naturally produces all the L-arginine you should need. However, if you wanted to avoid taking an L-arginine supplement and opt for a more natural way of getting L-arginine, dietary sources of L-arginine include:

  • Soy.

  • Fish.

  • Beans.

  • Poultry.

  • Dairy products.

  • Red meat (e.g. beef, lamb).

  • Whole grains (e.g. brown rice, whole-wheat bread). 

The Bottom Line

L-arginine plays an important role in synthesising nitric oxide (NO) - a vital molecule needed for strong erections. NO allows more blood to enter the penis, which results in stronger, firmer erections. Although a few studies show positive treatment results when using L-arginine for ED, more research into its effects could be undertaken. 

L-arginine can interact with some medications, so it is best to speak with your doctor before taking an L-arginine supplement to make sure it is safe for you to take.