Citrulline is one of the most popular pre-workout ingredients in sports. What is more, it is also gaining popularity in a health context.
Specialists have repeatedly wondered whether citrulline is better than arginine, or the other way around. Maybe it is worth finding some common ground and meeting halfway? First, though, get to know citrulline.
Citrulline – what is it and how does it work?
Citrulline is an amino acid that we are able to produce on our own, although many consider it an essential ingredient. The body's need for this amino acid may increase in disease states and during increased physical activity. In such cases, the amounts produced by the body will not be sufficient. It has a beneficial effect on the body and its properties can be used successfully not only in sport, but also in a health context.
Citrulline, alongside arginine and AAKG, is the most popular ingredient in
pre-workouts (pre-workout supplements) that cause the muscle pump effect. Its action is therefore closely linked to the endothelium and increased production of nitric oxide (NO). The effect of this is vasodilation, which leads to freer flow of blood, oxygen and nutrients to the muscles.
Athletes in physique sports (muscle building) and strength sports especially value this property. Muscles that are better supplied with blood, oxygen and recovery nutrients are stronger and larger muscles.
As a result, through supplementation with this amino acid, we increase the intensity and efficiency of training sessions, providing the muscles with a stronger growth stimulus. Anabolism, protein synthesis and the post-exercise recovery mechanism are improved.
Not only do more anabolic and nutritional components reach the muscles together with blood and oxygen, but we also increase the energy stores and improve the recovery of muscle fibres damaged by extreme exertion.
In addition to stimulating NO production, it is also involved in the urea cycle. As a result, urea is formed from ammonia, aspartate and carbon dioxide. Three specific amino acids are needed for the urea cycle to proceed - citrulline, arginine, ornithine.
This is important for the body because harmful ammonia, in larger amounts, is not accumulated but efficiently removed (filtered by the kidneys and eliminated from the body). Citrulline is essential for the optimal functioning of this mechanism.
Studies confirm that citrulline in the form of malate can reduce fatigue and mitigate its possible effects. What is more, through its external supplementation, not only was strength performance improved - longer and more demanding training sessions with the supplement were more likely. Supplementation improved both endurance and aerobic performance.
Stimulating nitric oxide production is not good only for skeletal muscles - it also supports maintaining the proper condition of the cardiovascular system, especially the heart muscle.
In addition, according to studies, increased NO production has a beneficial effect on glucose uptake by muscle cells. Increased nitric oxide production in people with type II diabetes was associated with insulin sensitivity. Some sources also mention a link between increased NO production and the activity of brown adipose tissue, which promotes the reduction of excessive body fat. Beyond the typical relationship with NO, citrulline influences the activation of serine/threonine protein kinase (mTOR), which is so important in the context of protein synthesis (including muscle protein synthesis).
In optimal amounts, citrulline can to some extent reduce the excessive excretion of important elements for the body, e.g. sodium, potassium, magnesium.
Citrulline or arginine?
Let's start with the fact that arginine is an amino acid needed by the body, and the supplement itself can do a lot of good both in sport and in a health context. The nature of arginine, combined with the action of the liver, may limit the ingredient's real potential. The point is, of course, that very large amounts of arginine - before entering the bloodstream - are retained and then broken down in the liver. As a result, only very small amounts can be used for the purposes we care about.
Taking the above information into account, a very good alternative is AAKG (or an addition of it), or a citrulline supplement. Citrulline does not work as strongly, but it is more stable, and the muscle pump effect and NO stimulation itself last longer. What is more, its addition in a supplement can increase the amount of arginine available and usable by the body. An additional advantage is the fact that citrulline supplementation also increases ornithine levels.
It is worth mentioning that its addition has a beneficial effect on phosphocreatine resynthesis and ATP production, which acts as an energy molecule and energy carrier. The combination of both amino acids - arginine + citrulline - gives great results, affecting sports performance and physical parameters. At the same time, it supports good health. A very good option is citrulline malate, that is, citrulline combined with malic acid, which also - even as a standalone supplement - will do its job. It has been confirmed that it affects energy production.
Citrulline – benefits of use
- stimulates NO production,
- supports post-exercise recovery,
- reduces muscle fibre breakdown,
- stimulates protein synthesis,
- supports the proper condition of the circulatory system and heart muscle,
- supports toxin elimination,
- contributes to more efficient production and use of energy,
- minimizes excessive loss of some other valuable components,
- has a beneficial effect on insulin sensitivity,
- reduces fatigue,
- improves performance and endurance,
- supports muscle building.
