The Significance of L-Citrulline
What Is Citrulline?
Citrulline is an amino acid that has been shown to have many beneficial roles when it comes to fitness and your workouts. More than likely you’ve tried citrulline in one form or another, probably in either a pre-workout or pump product. Citrulline can increase energy levels, reduce muscle fatigue, and enhance your muscle pumps! But did you know that citrulline can help boost fat loss too?
Citrulline’s Many Benefits
Citrulline is converted to another important amino acid in the body, arginine. This results in an increase in blood arginine levels, which can then feed the NOS-NO pathways of nitric oxide (NO) production. Increases in NO result in increased blood flow and nutrient delivery. Citrulline also helps reduce fatigue by playing a role in ATP (i.e., energy) production and also by reducing the buildup of ammonia, which can cut workouts short. In a nutshell, supplementation with citrulline can help maintain muscle pumps, sustain energy and endurance, and reduce post-workout muscle soreness. On top of all these benefits, it appears that citrulline may have one more: It can support increases in lean mass while reducing fat mass at the same time!
More Lean Muscle, Less Fat
A recent study shows that supplementing with citrulline can help change your body composition and reduce fat mass and increase lean mass by blocking the aging process. The study gave 20-week-old rats—considered “young elderly”—a 1 g/kg dose of citrulline every day for 12 weeks or 1 gram of a mixture of other nonessential amino acids. This would be equivalent to a 0.16 g/kg dose for humans. At the end of the study, the rats that received the citrulline had a very different body composition from the rats that didn’t receive it. The rats that received the citrulline had 13 percent less fat and 9 percent more lean mass than the group that received the nonessential amino acids.
Age Preventer, Fat Burner?
To much surprise, citrulline doesn’t appear to work on anabolic signals such as mTOR and leucine, but instead causes cells to manufacture a key protein involved in mitochondrial production called mitochondrial transcription factor A (TFAM). These proteins help repair and increase the number of mitochondria, the energy powerhouse of cells. Mitochondria are essential for energy production and increase the amount of ATP available to cells. They’re also involved in cell signaling, cell differentiation, and cell life cycle. As we age, the number of mitochondria in cells decreases, resulting in decreases in energy supply to surrounding tissue and the production of more free radicals that can cause damage to cells.
Although this study wasn’t performed in humans, there’s evidence to suggest that citrulline can have this effect in humans, as it has been shown to increase the rate of ATP production in humans. One thing’s for sure: Supplementing with citrulline will have beneficial effects on your energy, workouts, and possibly body composition too!
Moinard C, et al. Citrulline supplementation induces changes in body composition and limits age-related metabolic changes in healthy male rats. J Nutr. 2015;145(7):1429-37.
For more about L-Citrulline, and it's fat loss benefits, check out this article!