Can L-arginine Cure Erectile Dysfunction And Improve Libido?

L-arginine may be effective at helping you overcome erectile dysfunction

However, it will typically not increase your libido.

L-arginine helps you ‘get it up’ because it increases your production of nitric oxide

You simply need nitric oxide in order to get erections.

Because this is what opens the blood vessels in your penis, so that blood can flow into your penis and produce an erection.

If you don’t produce enough nitric oxide, you will find it almost impossible to get an erection. 

Let’s learn more about L-arginine.

Nitric oxide expands your blood vessels

What Is L-arginine?

L-arginine is an amino acid. One of many, because in your body you have more than 500 different amino acids. 

Yet there are two basic types of amino acids: 

  • Essential amino acids, and 
  • Semi-essential amino acids 

Essential amino acids cannot be synthesized in the body, so they have to be obtained via foods (or supplements). 

The semi-essential amino acids on the other hand, can be manufactured in your body.

L-arginine is one of the semi-essential amino acid. This means that you normally produce adequate amounts of it.

The 22 proteinogenic amino acids

However, certain people such as infants and people with particular health conditions, do not produce enough. They therefore need to get additional L-arginine either through foods or supplements. 

And even though your body in theory should produce enough of it, there are still several reasons why you may not produce enough. Particularly in the blood vessels in your penis. 

And this will in turn make it difficult to get erections.

Although there are more than 500 different amino acids, the most well-known are the 22 so-called proteinogenic amino acids. 

These are called proteinogenic because they are precursors to, or building blocks of, proteins. 

L-arginine, by the way, is also one of these proteinogenic amino acids.

L-arginine is a proteinogenic amino acid

When you eat food that contains proteins, your digestive system breaks down the proteins into proteinogenic amino acids. These are in turn re-assembled to the proteins your body needs. 

These newly formed proteins are then used to build and repair muscle, tissue, organs, skin, hair and other parts of your body.

Amino acids are also a source of energy, similar to fats and carbohydrates. 

In addition, amino acids transport nutrients and oxygen through the body, synthesize neurotransmitters, enable vitamins and minerals to perform their jobs properly, produce antibodies for the immune system, regulate gene expression and perform several other functions.

L-arginine is commonly found in foods such as dairy products, meat, seafood, grains, nuts, seeds, peas and beans. 

It was also first isolated in 1886 by a Swiss chemist.

L-arginine was first isolated in 1886 by a Swiss chemist

L-arginine plays an important role in overall metabolism, vasodilation, cell division, protein synthesis, the healing of wounds, removing waste products from the body, immune function, reducing insulin resistance and supporting bone growth.

It is also essential for getting erections and hence for avoiding erectile dysfunction.

Let’s understand how L-arginine helps you get erections.

L-arginine Helps You 'Get It Up' By Increasing Your Nitric Oxide Production

L-arginine does one very specific task: It provides you with building materials to produce nitric oxide.

Let me explain from the beginning: 

The inner lining of your blood vessels are covered with cells that are called endothelial cells.

Man with erection

Inside these endothelial cells sit a group of enzymes, called nitric oxide synthase. 

These are the ‘factories’ that produce nitric oxide.

And they do this by stealing a nitrogen atom from L-arginine, and combining it with an oxygen atom from molecular oxygen. 

So this is how your blood vessels create nitric oxide. 

But then what happens with this nitric oxide?

This nitric oxide is then diffused into what’s called the smooth muscles in your blood vessels.

Think of your blood vessels as a tube inside a tube inside a tube. One layer is the endothelial cells, another layer is the smooth muscles.

Smooth Muscles Relax To Provide Bloodlfow

The smooth muscles in the blood vessels in your penis are normally contracting. When they contract, they squeeze the blood out of these blood vessels.

This in turn causes your penis to be flaccid.


When nitric oxide is diffused into these smooth muscles, something happens. 😊

They start to relax.

And when they relax, they give up the tight squeeze around your blood vessels. Which means that blood is allowed to flow into these blood vessels.

When enough blood enters, your penis gets filled with blood and an erection forms.

Proper Bloodflow To Avoid Erectile Dysfunction

That is how you get an erection. And this is why nitric oxide is so important.

Let’s look at what the scientists have to say.

Scientific Studies On L-arginine’s Impact On Libido And Erectile Dysfunction

In this section, you find all the relevant scientific evidence that exists about L-arginine and its impact on sexual functions. 

Or at least, all the relevant scientific evidence that I am aware of. 😊

With this information all in one place, you can quickly draw your own conclusions. 

To help you, I have created a summary of the key findings from each of these scientific studies. And you also find a link to each of them, should you want to read the actual studies for yourself. 

I have presented all relevant research I am aware of, whether they indicated that the effect from L-arginine was positive or negative.

Scientific Studies On L-arginine’s Impact On Libido And Erectile Dysfunction

L-arginine Study 1: June 2020

The Daily Therapy With L-Arginine 2,500 mg and Tadalafil 5 mg in Combination and in Monotherapy for the Treatment of Erectile Dysfunction: A Prospective, Randomized Multicentre Study.

The goal of this study was to evaluate the effectiveness and tolerability of 5 mg of tadalafil and 2,500 mg of L-Arginine, in monotherapy and combination therapy.

The study included 300 men with erectile dysfunction. The men were put in three groups, and received the following treatment:

  • Group 1: L-arginine 2,500 mg
  • Group 2: Tadalafil 5 mg
  • Group 3: L-arginine 2,500 mg + Tadalafil 5 mg

The men received the treatment daily for 12 weeks.

The outcome?

The ED score for the men in the 3 groups increased as follows:

  • Group 1: 15.0 to 18.1
  • Group 2: 14.8 to 20.8
  • Group 3: 14.9 to 22.0

The group that took the combined treatment had a significantly larger improvement in erectile dysfunction score, than either of the single treatments.

But also the group that only received the L-arginine treatment, saw significant improvements.

Men taking L-arginine can overcome erectile dysfunction

L-arginine Study 2: February 2019

The Potential Role of Arginine Supplements on Erectile Dysfunction: A Systemic Review and Meta-Analysis.

The aim of this study was to assess the potential role of arginine supplements on ED as alternatives to phosphodiesterase inhibitors.

This study reviewed existing research studies that had been done on arginine supplements and erectile dysfunction. 

In total, 10 randomized controlled trials met the inclusion criteria, involving 540 patients with ED.

The outcome?

The study found that arginine supplements with dosage ranging from 1,500 to 5,000 mg significantly improved ED, compared with placebo or no treatment.

It also reported that arginine supplements caused significant improvements in the ED scores of overall satisfaction, intercourse satisfaction, orgasmic function, and erectile function, whereas the sexual desire score was unchanged.

Studies about arginine supplements and erectile dysfunction

L-arginine Study 3: March 2013

A randomized, double-blind, crossover, placebo-controlled comparative clinical trial of arginine aspartate plus adenosine monophosphate for the intermittent treatment of male erectile dysfunction.

The aim of this study was to analyze the efficacy and safety of 8,000 mg of L-arginine aspartate, combined with 200 mg of adenosine monophosphate, compared to a placebo, for intermittent treatment of mild-to-moderate erectile dysfunction.

This study was a double-blind, placebo-controlled, two-way crossover randomized clinical trial with 26 patients.

The supplements were administered orally, 1-2 hours before sexual intercourse.

The outcome?

The patients treated with L-arginine and adenosine monophosphate, demonstrated significant improvements in all ED domains with the exception of the sexual desire and orgasmic domains, compared with the placebo group.

Research study on L-arginine and adenosine monophosphate

L-arginine Study 4: February 2011

Bolus arginine supplementation affects neither muscle blood flow nor muscle protein synthesis in young men at rest or after resistance exercise.

The aim of this study was to investigate the ergogenic potential of arginine on nitric oxide synthesis, muscle blood flow, and skeletal muscle protein synthesis.

8 healthy young men participated in 2 leg resistance exercises and ingested a drink containing, either 10,000 mg L-arginine, or a placebo. The study lasted one day. 

The outcome?

The study found that 10,000 mg of arginine did not increase nitric oxide synthesis or muscle blood flow. Neither did it enhance mixed or myofibrillar skeletal muscle protein synthesis, either at rest or after resistance exercise.

Scientists investigating L-arginine

L-arginine Study 5: November 2010

Acute L-arginine supplementation reduces the O2 cost of moderate-intensity exercise and enhances high-intensity exercise tolerance.

The purpose of this study was to analyze whether dietary supplementation with L-arginine improves exercise efficiency and exercise tolerance in healthy humans.

9 healthy men (from 19-38 years of age) consumed a beverage containing 6 g of L-arginine, or a placebo beverage, and then completed a series of moderate- and severe-intensity exercises, 1 hour later.

The outcome?

In the L-arginine group, nitric oxide concentrations were 104% higher, blood pressure was 6% lower, steady-state oxygen uptake during moderate-intensity exercise was 7% lower, and time to exhaustion was extended by 26%.

L-arginine enhances high-intensity exercise tolerance

L-arginine Study 6: October 2004

L-Arginine and Atherothrombosis.

The aim of this study was to analyse the effects of L-arginine on endothelial function in patients with atherothrombosis (which is the formation of a blood clot within an artery as a result of atherosclerosis). 

The outcome?

The study indicated that acute or chronic administration of supplemental L-arginine enhances endothelial nitric oxide production, and improves endothelial function in the setting of atherothrombosis.

It found that L-arginine does this through:

  • Increased intracellular uptake via the high-affinity cationic transporter 
  • Substrate competition with asymmetric dimethylarginine 
  • A naturally occurring inhibitor of nitric oxide synthase 
  • Direct antioxidant activity 
  • Stimulated release of histamine from mast cells, which produces a vasodilator response 
  • Decreased activity of norepinephrine, which promotes the effect of endogenous vasodilators including nitric oxide 
  • Increased insulin secretion, which causes vasodilation

The study also found that L-arginine may have a negative effect on endothelial function, via creatine, but that the net effect of the supplement is positive.

L-arginine and atherothrombosis

L-arginine Study 7: June 2003

Treatment of erectile dysfunction with pycnogenol and L-arginine.

The aim of this study was to investigate the possibility of overcoming erectile dysfunction by increasing the amounts of endogenous nitric oxide with Pycnogenol (pine bark) and L-arginine.

The study included 40 men, aged 25-45 years, without confirmed organic erectile dysfunction. The study lasted for 3 months. 

The men were given 1,700 mg of L-arginine per day during the first month. 

During the second month, the men were given 1,700 mg of L-arginine + 80 mg of pine bark, per day.

And during the third month, the men were given 1,700 mg of L-arginine + 120 mg of pine bark, per day.

The outcome?

After the first month, 5% experienced normal erections. After the following month, 80% experienced normal erections. And after the third month, 92.5% of the men experienced normal erections.

Treatment of erectile dysfunction with pycnogenol and L-arginine

L-arginine Study 8: December 2002

Oral L-arginine improves endothelial dysfunction in patients with essential hypertension.

The goal of this study was to evaluate the nitrate-induced, endothelium-independent vasodilatation from L-arginine in patients with essential hypertension.

35 patients with essential hypertension received either 6,000 mg of L-arginine, or a placebo.

Patients were then examined for flow-mediated endothelium-dependent dilatation of the brachial artery (the major blood vessel of the upper arm), before and 1.5 hour after administration of the L-arginine, or the placebo.

The outcome?

The study concluded that administration of L-arginine acutely improved endothelium-dependent, flow-mediated blood vessel dilatation by more than 300% in these patients.

Oral L-arginine improves endothelial dysfunction in patients with essential hypertension

L-arginine Study 9: June 2002

Efficacy and safety of a novel combination of L-arginine glutamate and yohimbine hydrochloride: a new oral therapy for erectile dysfunction.

The goal of this study was to compare the efficacy and safety of the combination of 6,000 mg of L-arginine glutamate and 6 mg of yohimbine hydrochloride, with that of 6 mg of yohimbine hydrochloride alone, and that of placebo alone, for the treatment of erectile dysfunction.

The study included 45 men with moderate erectile dysfunction, and lasted for 4 weeks.

During each of the 2-week, crossover periods, the supplements were administered orally, one to two hours before intended sexual intercourse.

The outcome?

The group receiving the L-arginine + yohimbine supplement, saw a 22% improvement in ED score.

The study concluded that administration of 6,000 mg of L-arginine and 6 mg yohimbine is effective in improving erectile function in patients with mild to moderate ED.

L-arginine and yohimbine for erectile dysfunction

L-arginine Study 10: December 2001

Effect of oral administration of high-dose nitric oxide donor L-arginine in men with organic erectile dysfunction: results of a double-blind, randomized, placebo-controlled study.

The purpose of this study was to determine, in a prospective randomized, double-blind placebo-controlled study, the effect of 6 weeks of 5,000 mg/day L-arginine on men with organic erectile dysfunction.

The study included 50 men with confirmed organic ED. They first went through a 2-week placebo run-in period, and then received 5,000 mg/day L-arginine, or a placebo.

The outcome? 

Oral administration of L-arginine in high doses seemed to cause significant subjective improvement in sexual function in men with organic ED, but only if they already have decreased nitric oxide excretion or production.

L-arginine study to treat erectile dysfunction

L-arginine Study 11: February 1999

Effectiveness of oral L-arginine in first-line treatment of erectile dysfunction in a controlled crossover study.

The purpose of this study was to examine the effectiveness and safety of L-arginine, in the treatment of mixed-type impotence.

32 patients with impotence and with a mean age of 51.6 years, enrolled in the study. They were given 1,500 mg per day of L-arginine, or a placebo, for 17 days. Then the groups were switched.

The outcome?

1,500 mg/day of L-arginine is not better than placebo as a first-line treatment for mixed-type ED.

L-arginine as first-line treatment of erectile dysfunction

L-arginine Study 12: September 1997

Effects of long-term oral administration of L-arginine on the rat erectile response.

The aim of this study was to determine whether dietary supplementation of L-arginine can stimulate penile erection, and whether ancillary pathways for penile erection may exist. 

Adult male (5 months old) and aged (20 months old) rats were fed L-arginine dissolved in tap water, for 8 weeks.

The outcome?

After 8 weeks, the maximal intracavernosal pressure was increased by 21% in the adult group, and 32% in the aged group, compared to the control group.

Also, penile nitric oxide synthase activity was increased by almost 100% in the L-arginine treated groups, vs. the control group.

L-arginine's effect on the rat erectile response

Is L-citrulline Better Than L-arginine?

The goal of supplementing with L-arginine, is to deliver this L-arginine to the enzyme nitric oxide synthase. 

This way, nitric oxide synthase can use this L-arginine to produce nitric oxide. Which you need in order to get erections.

However, supplementing with L-arginine may not be the optimal way to get L-arginine to your nitric oxide synthase.


Because your gut and liver break it down. So that in the end, only a small amount of the L-arginine actually reaches the end destination.

Research has indicated that as much as 38-75% of the L-arginine is lost on the way.

The human body

Therefore, you may be better off supplementing with L-citrulline instead.


Because it does not undergo transformations in your gut or liver (or at least to a much smaller extent).


When it reaches your kidneys, it is transformed to L-arginine. 

Which means that essentially all the L-citrulline converts to L-arginine, which is then available for nitric oxide production.  

This is what you want.

Let’s have a look at what research says about this.

Scientific research on L-citrulline

L-citrulline Study 1: June 2019

The Effects of Oral L-Arginine and L-Citrulline Supplementation on Blood Pressure.

The aim of this study was to investigate whether oral administration of the amino acids L-arginine and L-citrulline could effectively reduce blood pressure by increasing nitric oxide production.

The outcome?

The study suggested that oral L-arginine supplementation can lower blood pressure by 5.39/2.66 mmHg.

And that oral L-citrulline supplementation can lower blood pressure in the range of 4.1/2.08 to 7.54/3.77 mmHg.

citrulline-is-more-efficient-than-arginine for ED

L-citrulline Study 2: April 2017

Supplemental Citrulline Is More Efficient Than Arginine in Increasing Systemic Arginine Availability in Mice.

The purpose of this study was to determine the relative efficiency of arginine and citrulline supplementation to improve arginine availability.

Male mice were adapted to 1 of 7 experimental diets for 2 weeks. The basal diet contained 2,500 mg L-arginine/kg, whereas the supplemented diets contained an additional 2,500, 7,500, and 12,500 mg/kg diet of either L-arginine or L-citrulline.

On the final day, after a 3-hour food deprivation, the mice were continuously infused with a diet similar to the dietary treatment, along with L-arginine, to determine the first-pass metabolism FPM (extent of breakdown) of L-arginine.

The result? 

Supplemental arginine underwent an ∼70% FPM, indicating that only 30% was available for nitric oxide production.

The study also found that L-citrulline increased arginine concentrations by 35% more than did L-arginine.

L-citrulline supplementation improves erectile function

L-citrulline Study 3: October 2013

Oral L-citrulline supplementation improves erectile function in rats with acute arteriogenic erectile dysfunction.

The goal of this study was to investigate whether oral L-citrulline supplementation improves erectile function in rats with acute arteriogenic erectile dysfunction.

Rats were divided into three groups: A control group, a group where ED was provoked, and a group where ED was provoked and the rats received L-citrulline. 

The study lasted for 4 weeks.

The outcome?

The rats who received L-citrulline had significantly improved intracavernous pressure / mean arterial pressure, more smooth muscle expression and higher nitric oxide levels, compared to the group who did not receive L-citrulline.

L-citrulline can be effective at treating erectile dysfunction

L-citrulline Study 4: April 2012

Restoration of impaired nitric oxide production in MELAS syndrome with citrulline and arginine supplementation.

The goal of this study was to assess nitric oxide production in subjects with MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) and the effect of the nitric oxide precursors arginine and citrulline.

The outcome?

Arginine and, to a greater extent, citrulline supplementation increased the arginine synthesis rate, the plasma concentrations and flux of arginine and citrulline, and nitric oxide production. 

The study concluded that citrulline supplementation was superior at increasing nitric oxide production.

L-citrulline increases nitric oxide production

L-citrulline Study 5: January 2011

Oral L-citrulline supplementation improves erection hardness in men with mild erectile dysfunction.

The aim of this study was to test the efficacy and safety of oral L-citrulline supplementation in improving erection hardness in patients with mild erectile dysfunction

The study included 24 men with an average age of 56.5 years, who had mild ED. They were given 1,500 mg of placebo for one month, and then 1,500 mg of L-citrulline for the following month.

The outcome?

50% of the men given L-citrulline reported improvement in erection hardness.

The mean number of intercourses per month also increased 68% for the men given L-citrulline.

L-citrulline supplementation improves erection hardness

L-arginine Study 6: October 2007

Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine: impact on nitric oxide metabolism.

The purpose of this study was to assess the metabolic conversion and subsequent pharmacodynamic effects of L-citrulline and L-arginine.

20 healthy volunteers received six different dosing regimes of placebo, citrulline, and arginine. 

For 7 days, the participants received either: 

  • L‐citrulline 750 mg twice daily 
  • L‐citrulline 1,500 mg twice daily 
  • L‐citrulline 3,000 mg twice daily 
  • L-arginine immediate‐release 1,000 mg 
  • L-arginine sustained‐release 1,600 mg twice daily 
  • Placebo

Pharmacokinetic parameters were calculated after 1 week of supplementation.

The result?

L‐citrulline increased plasma L-arginine concentration and augmented nitric oxide-dependent signalling, more effectively than L-arginine.

L-citrulline increases nitric oxide better than L-arginine

Other Potential Health Benefits From L-arginine And L-citrulline

In addition to its potentially beneficial effects on erectile functioning, L-arginine is also used for heart and blood vessel conditions including congestive heart failure, chest pain, high blood pressure, coronary artery disease, blood clots and stroke. 

Some people also use L-arginine for preventing the common cold, reducing healing time of injuries, improving athletic performance, boosting the immune system, stimulating the release of growth hormone, increasing bone strength and preventing inflammation.

L-arginine is also reported to improve sperm production and sperm motility.

Let me tell you about my experience taking L-arginine and L-citrulline.

Health benefits from L-arginine

My Experience With L-arginine And L-Citrulline Supplements

  • Form: Loose powder
  • Dose: One tablespoon (not fully topped) (approximately 7 grams)
  • When: 60-120 minutes before sex
  • Effect on libido: None
  • Effect on erection: Good
  • Effect on sensation: None
  • Taste: Neutral (L-citrulline has a citrusy taste)
  • Verdict: A very nice one that I use every time I take supplements 👍
  • Noticed side-effects: None

The first time I tried L-arginine, I took 1,5 grams in capsule form in the mornings before heading to work. 

I recall one morning, sitting on the bus minding my own business. All of a sudden I had an erection! It came out of nowhere.

Bus in London

To me, this was highly unusual. I mean, I was struggling with erectile dysfunction at the time, and would normally never get spontaneous erections.

I also had a few other episodes with spontaneous erections after taking L-arginine. But it was nothing consistent or predictable.

Hence taking 1.5 grams of L-arginine in the morning did not help me overcome my ED.

I also tried taking 1.5 grams of L-arginine before sex. 

I noticed improvements at times, but it was not consistent. Hence, 1.5 grams of L-arginine alone was not able to help me with erectile dysfunction.

Therefore, I increased the dose to what I used for most of the herbal supplements: To 7 grams.

Man in boxer with erection

I mixed one tablespoon (not fully topped) of the powder (about 7 grams) with cold water. I stirred until the powder was dissolved, and then drank it. I did this about one hour before sex. 

To me, L-arginine has no taste, so taste-wise taking this was pretty much just like drinking water. 

And taking 7 grams had a much more profound effect than taking just 1.5 grams. To me, this did produce noticeable results. 

This normally made my erections stronger, fuller and longer lasting. 

However, now I no longer take L-arginine. I have switched to L-citrulline. 

Because it produces even better and more consistent results.

One tablespoon L-arginine (L-citrulline)

With L-citrulline, my erections are stronger and the results are more reliable than with L-arginine. 

And by the way, L-citrulline has a ‘citrusy’ taste. It’s sharp, but by no means bad, at least in my opinion.

Although L-citrulline (or L-arginine) has helped me getting erections, I have not noticed any increase in libido or any increase in pleasurable sensations from sex, after taking this supplement.

This is probably because the supplements only work via the nitric oxide channel. It has no documented effect on either testosterone or dopamine

And when I take supplements today, I normally don’t just take L-citrulline.

When I take supplements, I typically always take more than one. I do this because the combined effect of taking several supplements, is significantly better than just taking one supplement alone.

Combination of supplements for erectile dysfunction

And L-citrulline is normally always included in the combination I take. 

This is my favorite combination:

This combination gives me erections that are on par with erections I got when I was taking pharmaceutical drugs.

Also, it makes the pleasurable sensations from sex even more intense. 

If you want to purchase a high quality version of L-citrulline or L-arginine, you find it here.

And if you want to learn how to cure ED naturally and permanently, you can read this guide.

Let’s finish off with a few words about safety.

How you can cure erectile dysfunction with L-arginine

Safety Of L-citrulline And L-arginine

Is it safe to take L-citrulline or L-arginine in the doses that I have taken? Which is about 7 grams.

The answer is that I don’t know.

I am not a doctor and I don’t know for sure. 

That said, studies have indicated that several grams L-arginine has been well tolerated by the body, in the short term.

And what I can say, is that I have never experienced any side effects from taking L-citrulline or L-arginine in these doses. And I have taken these supplements on multiple occasions, and over several years.

However, this does not mean it is 100% safe.

There is also a chance that your body may react differently than my body does.

Therefore, should you want to try these supplements in the doses that I have taken, you do this 100% at your own risk.

Comments Off on L-Arginine