L-Citrulline, L-Arginine and Erectile Dysfunction

In this article, we are going to learn more about two natural substances – L-Arginine and L-Citrulline and their efficacy in erectile dysfunction treatment.

Regardless of its causes, ED can cause serious phycological discomfort and decreases the life quality. Erectile dysfunction, both mild and severe is a pretty frequent problem in men.

There are a lot of medicines that affect the “technical” aspect of the problem: they just help to reach and maintain strong erection without affecting the mechanism of penis vascular strength and treating the potential causes. To put it simply: when a person gives up taking Viagra, everything flips back.

Other types of medications are used in severe cases and they show high effectiveness, although can have serious adverse effects. So if the problem is not severe enough, it is understandable, why people avoid exposing their bodies to heavy-duty prescription drugs.

When it comes to ED therapy, it is safe to use natural substances. Furthermore, they are scientifically-proved and are sold without prescription in a drugstore or at a sport supplements store. We are talking about two important amino acids: L-Arginine and L-Citrulline.

What are L-Arginine and L-Citrulline amino acids?

Every macronutrient has simple compounds. If you imagine a protein molecule as a building, then amino acids are building blocks. Amino acids are vital for proper functioning of the body. Some of them take part in metabolism, while others are necessary to produce hormones and some are essential in building up muscles.

Some amino acids fulfill a few functions at once. Arginine and Citrulline are one of them. Most often, these two amino acids are used by athletes and bodybuilders for faster recovery, improved production of human growth hormone, better muscle supply with blood and nutrients, and nitric oxide production for muscular pumping. The latter function is also a key to long-lasting and strong erections.

There are two types of amino acids: essential and non-essential. The first group cannot be produced in the organism from other substances and have to be consumed with foods or supplements. The latter group can be synthesized in the body using other amino acids. L-Arginine is a semi-essential amino acid, i.e. the body is able to produce it from other amino acids and get directly from some products. This amino acid was first isolated and described by a Swiss scientist at the end of 19th century. Arginine is necessary for proper cell division, protein synthesis, recovery processes in the body and insulin resistance reduction. Besides, arginine is vital for bone growth and excretion of waste substances from the body.

Under some circumstances, the body is not able to produce enough of L-Arginine. It may lead to weaker erections. L-Arginine is necessary for the endothelium (the inner lining of blood vessels) to produce nitric oxide.

L-Citrulline is another semi-essential amino acid, it is able to transform to L-Arginine. L-Citrulline is able to enter the kidneys and increase the plasma L-Arginine concentration and to augment NO-dependent signaling. A cross-over study proved that L-Citrulline performs that more effectively in comparison with L-Arginine. After than a few other studies were conducted, it was discovered that the best results were achieved from the combination of these two amino acids. The research controlled the following aspects: the erection hardness score, the number of sexual intercourses per one month and satisfaction score along with possible adverse effects.

The scientists were encourage to find no adverse effects from supplementation with L-Arginine and L-Citrulline in the dosages specified in the instruction. One of the most outstanding findings of the overall research conducted with L-Arginine and L-Citrulline is that L-Citrulline intake corrects the cause of ED, the PDE5 inhibitors (for example, popular Viagra, Levitra, Cialis) do not.

The study of 2008 showed that increased nitric oxide production leads to corpus cavernosum smooth muscle cell production along with synthesis of VEGF or vascular endothelial growth factor. It is able to help the restore the inner lining of blood vessels. All these factors let us resume that proper L-Arginine and L-Citrulline supplementation can manage and even treat penile endothelial dysfunction and help in dealing with ED.

How does nitric oxide work?

Nitric oxide (also known as NO) is an organic chemical substance that can be naturally found in the blood. Nitric oxide is a great vasodilator. i.e. it helps to improve the blood vessel capacity and pump more blood to certain body parts. In case of hard workouts, we talk about muscles. In case of sexually stimulated male organ, we definitely mean this very organ. Nitric oxide is a physiologic signal for the body to produce penile erection.

Vasodilators are great in treating erectile dysfunction as they relax and widen the walls of blood vessels, helping the blood to reach the target areas freely. Naturally, during sexual arousement, the amount of nitric oxide in the body increases, but some research conducted in 2017 show that a significant proportion of erectile dysfunction patients have low L-Arginine or L-Citrulline level. Additional intake of L-Citrulline showed that 50% of patients noticed a higher erection hardness and more satisfaction in comparison to 8% of patients taking placebo. That sounds quite promising for a completely safe substance that can’t even be called a drug.

Scientific source:

  • ncbi.nlm.nih.gov/pubmed/28178400
  • ncbi.nlm.nih.gov/pubmed/21195829

L-Arginine and L-Citrulline work synergistically to stimulate the production of nitric oxide in the body. To get deeper in chemistry, L-Citrulline is transformed into L-Arginine after its intake during the process known as nitric oxide synthase. L-Arginine is absorbed right away and is evaluated as a more potent amino acid for stimulation of the nitric oxide production. This is proved by independent research of sport supplement manufacturers, who include L-Arginine in many pre-workout boosters and recovery supplements, while L-Citrulline is rarely manufactured as a single amino-acid in a supplement.

The reason, why it is recommended taking L-Arginine and L-Citrulline together is that they ensure a quick, but prolonged action of nitric oxide. While L-Arginine is absorbed almost immediately, it works for a shorter time. By the time it wears off, L-Citrulline comes into the game and provides a prolonged stimulation for nitric oxide production.

Regular intake of these amino acids is safe and effective. It works with the cause of ED: low levels of nitric oxide and not just masking a problem as Viagra, Cialis or Levitra do.

How to get enough L-Arginine and L-citrulline?

Plenty of these two amino acids can be found in products rich in full-fledged proteins.

To these products belong:

  • Meat (red), fish, poultry;
  • Nuts, seeds, wheat germ; beans;
  • Dairy products rich in protein;
  • Watermelons.

However, it is difficult to consume large amounts of these foods without gaining too many calories and gaining weight or overloading the digestive system and kidney. Proper nutrition should be a basis for filling the gap in L-Arginine and L-Citrulline supply. A very effective way to get enough amino acids for nitric oxide production is supplementing. Supplements with L-Arginine and L-Citrulline and tested and FDA-approved. Pay attention to the quality of the supplements and choose trusted manufacturers. As mentioned above, you can either look for these amino acids at a pharmacy or at a sport supplement store. The latter variant is perfect as no one will ever discover the real purpose of taking these amino acids.

As L-Arginine and L-Citrulline aren’t medications, they have no unwanted side-effects in case of following the instructions on the package. Overdosing is not recommended as it may lead to serious troubles with the digestive tract.

What are the recommended dosages of L-Arginine and L-Citrulline amino acids for ED treatment?

The dosage strongly varies depending on the weight, age and metabolism level, but it is wise to stick to the instructions listed on the package. L-Arginine supplements usually imply a single dose of 5 g of L-Arginine with 15 g per day. For L-Citrulline the recommended dosage is smaller: about 3 g per day divided in a few parts. It is convenient to take supplements with food.

Pros and Cons of treating ED with L-Arginine and L-Citrulline

The only side effect of L-Arginine and L-Citrulline likely to appear in case of individual sensitivity or overdosage is upset stomach and diarrhea.

Most studies of these two amino acids set as an object the benefits of L-Arginine and L-Citrulline for professional athletes and for males diagnosed with ED. Nevertheless, there is a recent breakthrough research that shows effectiveness of L-Arginine and L-Citrulline for heart diseases therapy.

Possible cons of L-Arginine and L-Citrulline intake include no data comparing the effectiveness of amino acids and the effectiveness of conventional medicines for erectile dysfunction. In case, the patient doesn’t want “hardcore” therapy with serious medications that have a lot of contraindications and side effects, L-Arginine and L-Citrulline is a great alternative.


To sum up, L-Arginine and L-Citrulline provide a safe and easily tolerated way to improve the hardness of erections, the sexual intercourse duration and, as a bonus, to improve athletic performance and decrease possible risk of heart diseases.