Citrulline is an amino acid that’s often associated with enhancing blood flow and producing “the pump.”
However, research suggests that citrulline provides other athlete-specific benefits that warrant its use. Best of all, it appears that citrulline is applicable for almost any athlete.
To come, we’ll discuss citrulline and cover its most powerful benefits for enhanced athletic performance.
What Is Citrulline?
Before learning how citrulline is beneficial for performance, it's essential to understand what citrulline is and why you might use it.
Citrulline is an amino acid derived most notably from watermelon and other citrus fruits. However, this amino acid is a bit different from those you might be familiar with because its purpose is not to produce proteins (1).
Instead, citrulline acts as a precursor to a different amino acid known as arginine.
Chances are, you’ve heard of arginine before because it’s been popularized as a primary amino acid responsible for producing nitric oxide (2).
Nitric oxide, as you might know, is a molecule responsible for dilating and relaxing blood vessels, which improves the chances of experiencing “the pump” when lifting weights (3).
The fascinating thing here is that supplemental arginine is extensively metabolized in the liver when you ingest it, which means that it's not a great supplement. Citrulline, however, bypasses this process and converts to arginine, in effect, elevating arginine levels to produce nitric oxide (1, 4, 5).
But helping you gain a pump isn’t the only reason for using citrulline, especially if you’re an athlete.
Studies show that citrulline might improve athletic performance in several different ways, including limiting fatigue, enhancing energy metabolism, and even improving recovery from a molecular and physical standpoint (6, 7, 8).
Together, it’s clear that the benefits of citrulline warrant its use in your supplement routine.
The Benefits Of Supplemental Citrulline
Even though citrulline’s ability to elevate arginine levels better than supplemental arginine itself is enough to warrant its use, there are a few distinct benefits of citrulline for athletic performance.
Citrulline Limits Fatigue & Enhances Performance
A primary reason that citrulline is in Cardio Surge Energy is because of its proven track record in limiting fatigue (6).
What's fascinating about citrulline for the athlete is its ability to limit fatigue at the end of the most intensive training programs, which could also translate to maintained performance later during athletic events when other athletes are too fatigued to maintain intensity.
For instance, in one fascinating study, researchers recruited recreationally trained males and exposed them to a hardcore training session, meant to elevate fatigue enough to reduce performance significantly.
During this study, each participant consumed either a citrulline-containing drink or an indistinguishable placebo and performed different workouts throughout the week. Most importantly, they were tested on their performance during an intense upper body workout.
For this workout, each subject had to complete four sets of flat bench with 80% of their one-rep maximum to failure, with only one minute of rest between sets. Then, the subjects performed four sets of incline press and four additional sets of incline dumbbell flies (6).
But, the workout didn’t stop there.
After completing their first 12 sets, each participant was instructed to perform an additional four sets of flat bench to failure, using 80% of their one-rep maximum.
It was during these sets was where citrulline proved its worth.
The researchers discovered that when participants used citrulline before training, they performed significantly more repetitions during the 15th and 16th set compared to placebo (6).
In fact, citrulline users performed 34% more reps on set 15 and approximately 53% more reps on the last set than placebo subjects (6).
For the athlete, performing more than 50% better when it counts could be the difference between losing and crushing the competition.
Citrulline Enhances Energy Metabolism & Replenishment
A significant factor influencing athletic performance is your body's ability to metabolize and replenish the energy that you're using efficiently.
Fortunately, the citrulline found in Cardio Surge Energy might help in a few different ways.
Citrulline Limits Phosphocreatine Depletion & Enhances Replenishment
For high-intensity activities like sprinting or heavy weightlifting, the body can't metabolize sugar or fat fast enough to meet energy demands. Instead, your muscles rely on phosphocreatine (PCr), which donates its phosphate group, releasing high amounts of energy (9).
In fact, the purpose of using creatine is to saturate your muscles with phosphocreatine for continued force and power generation.
Interestingly, one study in rats showed that supplemental citrulline significantly limited the depletion of PCr during muscle contraction. Primarily, the rat's muscles provided the same force but did so while using less energy (7).
But citrulline doesn’t just make energy usage more efficient; it appears to improve replenishment as well, making it a smart ingredient found in Recover Surge.
In fact, one study in males with fatigue showed that supplementing with citrulline significantly enhanced PCr replenishment after exercise. This means citrulline could improve your ability to produce high amounts of power and force repeatedly. (8).
Citrulline Enhances Aerobic Energy Production
For muscle contraction, the body relies on three different energy systems, using phosphocreatine, glucose (sugar), or fat to provide energy in the form of ATP.
However, each of these systems has limits.
The PCr system provides energy very rapidly but depletes quickly as well. Glucose metabolism is relatively rapid but doesn't offer a large number of ATP molecules.
Fat metabolism, or aerobic metabolism, is a slow process but yields the most energy (ATP molecules) in return.
The problem is that for aerobic metabolism to take control, intensity typically needs to be a bit lower. If energy demands are high, there's not enough time for aerobic metabolism to provide the energy required to sustain performance.
Amazingly, citrulline appears to enhance the ability for aerobic metabolism to provide energy. According to one study, when given citrulline, male participants showed enhanced aerobic metabolism during exercise compared to baseline (8).
The main advantage of enhancing aerobic energy production is that doing so can help your body save PCr and glucose, which can be valuable if you need to perform at a higher intensity later during a workout or event.
Citrulline Enhances Recovery
Being an athlete, you know just how important recovery is for growth and even continued performance. If there’s one reason that citrulline is included in Recover Surge it’s because citrulline enhances recovery and limits soreness (6).
If you're too sore from training, you'll lack motivation and perhaps even have to train at a lower intensity – not something you want if you're striving to be the best athlete.
Fortunately, the same researchers who tested citrulline with the intense chest workout also measured each participant’s perceived soreness and recovery 24 and 48 hours after the training session.
They found that when subjects used citrulline, they reported approximately 40% less soreness than subjects who took a placebo, at both 24 and 48 hours (6).
This reduction in soreness means enhanced recovery, allowing you to train harder and to train again sooner, which is a key factor in beating the competition.
Even though most people use citrulline to gain a pump, it appears that its effects are wide-reaching and can seriously enhance performance and recovery.
Studies suggest that using citrulline can enhance performance and also improve your ability to recover, which means you can train harder and do so more frequently (6, 7, 8).
If you’re an athlete looking to train harder and longer, the performance and recovery-enhancing benefits of citrulline make it a smart choice.
- Bahri, S., Zerrouk, N., Aussel, C., Moinard, C., Crenn, P., Curis, E., ... & Sfar, S. (2013). Citrulline: from metabolism to therapeutic use. Nutrition, 29(3), 479-484.
- Wu, G., & Morris Jr, S. M. (1998). Arginine metabolism: nitric oxide and beyond. Biochemical Journal, 336(1), 1-17.
- Bode-Böger, S. M., Böger, R. H., Alfke, H., Heinzel, D., Tsikas, D., Creutzig, A., ... & Frölich, J. C. (1996). L-Arginine induces nitric oxide–dependent vasodilation in patients with critical limb ischemia: a randomized, controlled study. Circulation, 93(1), 85-90.
- Osowska, S., Moinard, C., Loi, C., Neveux, N., & Cynober, L. (2004). Citrulline increases arginine pools and restores nitrogen balance after massive intestinal resection. Gut, 53(12), 1781-1786.
- Curis, E, Crenn, P, and Cynober, L. Citrulline and the gut. Curr Opin Clin Nutr Metab Care 10: 620-626, 2007.
- Pérez-Guisado, J., & Jakeman, P. M. (2010). Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. The Journal of Strength & Conditioning Research, 24(5), 1215-1222.
- Giannesini, B., Le Fur, Y., Cozzone, P. J., Verleye, M., Le Guern, M. E., & Bendahan, D. (2011). Citrulline malate supplementation increases muscle efficiency in rat skeletal muscle. European journal of pharmacology, 667(1-3), 100-104.
- Bendahan, D., Mattei, J. P., Ghattas, B., Confort-Gouny, S., Le Guern, M. E., & Cozzone, P. J. (2002). Citrulline/malate promotes aerobic energy production in human exercising muscle. British journal of sports medicine, 36(4), 282-289.
- Wadley, G., & Le Rossignol, P. (1998). The relationship between repeated sprint ability and the aerobic and anaerobic energy systems. Journal of Science and Medicine in Sport, 1(2), 100-110.