Citrulline under scrutiny: correct dosage, effects and our experience

In the next article of our series "Supplements under the microscope" we will introduce you to a supplement that is often hidden in the shadows of the glowe of proteins, BCAAs and similar supplements, but it has a huge number of benefits and by supplementing it you can achieve significant improvements.

As you can probably tell from the title of the article, it is citrulline.

What is citrulline

Citrulline is a non-essential amino acid formed by combining ornithine with carbamoyl phosphate. It plays an important role in the body as a precursor to arginine and oxaloacetate.

Due to its ability to be converted into arginine, it also brings a large number of positives. Many scientific studies have shown its effect on reducing muscle soreness, promoting athletic performance and stimulating growth hormone production.

How is citrulline produced in the body in the first place?

Citrulline is produced in the body by a process called urea (sometimes also called ureosynthetic) cycle, which is one of the primary ways humans remove nitrogen from the body. This entire cycle begins with the reaction of ammonia with carbon dioxide, which produces carbamoyl phosphate and ADP and inorganic phosphate. It is carbamoyl phosphate that enters into a reaction with ornithine and so citrulline is synthesized.

All these reactions used to take place in the matrix of the mitochondria, but now the whole process is transferred to the cytosol of the cells....where the reaction of citrulline with ATP and aspartate becomes argininosuccinate, then arginine, which is then broken down into urea and ornithine. Uric acid then leaves the body in the urine, ornithine remains in the body.

Effects and benefits of citrulline

Citrulline is a supplement packed with benefits. It improves protein synthesis, amino acid synthesis and even creatine synthesis during exercise. It is similar to the effects of arginine, however, since citrulline is yet to be broken down into arginine in the body, it can increase its levels for a longer period of time. So let's take a look at the most important benefits of this supplement:

Increase NO (nitric oxide) levels

Increasing nitric oxide levels is the main reason why most people take citrulline. Nitric oxide is one of the most important reasons why people use nitric oxide, because it plays quite a crucial role in muscle oxygenation, it can meltthe blood vessels and therefore increase blood flow and nutrient supply to the working muscle. As a result, this can not only lead to better recovery and muscle growth, but also to an increase in the time the muscle is able to sustain under tension.

Reduction of ammonia levels in the body

To understand the principle of how ammonia levels in the body are reduced, it is necessary to understand the urea cycle we described in the introduction. Simply put, the idea is that the source of nitrogen in the body is protein, and athletes often have an excess of protein. And it is the urea cycle that is supposed to remove the excess nitrogen in the form of hydrophilic urea. So when you supplement with citrulline, ammonia is removed from the body better and there is no accumulation in the body.

Other benefits of citrulline include:

• Increases levels of anabolic hormones (TST and RH).
• Helps minimize the risk of overtraining
• Delays and attenuates the onset of immunosuppressive symptoms during training (i.e. suppressing immune reactivity)
• According to some evidence, lowers blood pressure

Citrulline dosage

Basically, it is necessary to distinguish which citrulline you have bought. There are two basic types - citrulline malate (where the citrulline is bound to the malic anion) and l-citrulline, a completely pure 100% form of this supplement. And the dosage depends on the variant.

According to scientific studies, the ideal pre-workout dose of citrulline is at least 3 grams of pure citrulline and at least 5g of malate.If this minimum amount does not work for you, you can try the dosage according to this study. This is research conducted on athletes where subjects were given a dose of 8g to 10g of citrulline malate before training. This then led to better performance, more reps performed and lower pain scores.

Citrulline vs. arginine

As we hinted a few lines above, citrulline and arginine are somewhat similar. However, several studies have been done that have shown that citrulline can increase arginine levels in the body much more effectively than arginine alone.

You can see a clear comparison of the two supplements in the picture below:

What is the difference between l-citrulline and citrulline malate?

If you have been looking for supplements containing citrulline, you will have noticed several different "versions". But do you know the difference between them and which one to choose?

There is practically speaking only one difference. While l-citrulline is completely pure citrulline of pharmaceutical quality, citrulline malate is enriched with malate, or if you want to put it in English, malic acid. The latter is added to it primarily for its involvement in the Krebs cycle, which is considered the largest source of ATP production for the body. But that's getting too far off topic.

But the importance and effect of both types of citrulline is more or less the same. Citrulline crosses the mitochondrial membrane and thus enters the mitochondria. There, adenosine triphosphate (ATP) is formed, which is an essential fuel for the organism. Thanks to this, it has a positive effect on delaying fatigue and increasing strength during exercise.

Citrulline in food

You won't find many sources of citrulline in nature. One of the few known sources is watermelon, which contains a full 1mg of citrulline per 1g of melon. For the record, the name citrulline itself comes from the Latin citrullus, or watermelon.

Which one to choose?

If you choose to supplement with citrulline as a standalone supplement, it is most important that it contains 100% citrulline (an extract offlavored versions are an option, but even there there should not be too much added substances). The second criterion should be the price.

We can recommend the following supplements:

Personal experience

Of course, I have a lot of personal experience with citrulline, its supplementation is important especially before training. You will definitely notice better blood circulation in your muscles when taking it and, with long-term use, a delay in fatigue from training. I've never used it myself, but it is definitely a more than suitable ingredient in pre-workouts (as evidenced by by the fact that every good pre-workout on the market contains it) and it is also useful when creating your own pre-workout.

Do you have any questions for us about taking citrulline? Feel free to ask in the comments, we'd love to answer.

Previous parts:

• Joint Nutrition Under Scrutiny.
• BCAAs under the microscope: benefits, proper dosage and side effects
• Glutamine under the microscope: proper dosage, effects and our experience
• Creatine under the microscope: How it works in the body, its benefits and side effects
• Whey protein under the microscope: manufacturing processes, protein breakdown and its benefits
• Pre-workouts under the microscope: Uses, active ingredients and negative effects
• Omega 3 under the microscope: Proper dosage and healthbenefits
• Magnesium under the microscope: Benefits, dosage and its best forms
• Vitamin D3: Benefits, proper dosage and best form
• EAAs under the microscope: proper dosage, effects and supplement reviews

Everything you need to know about citrulline (video):