What do serious bodybuilders and other strength athletes desire most? More muscle, fast? More strength and stamina to train harder and for longer? More energy? Intense muscle pumps? It comes as no surprise that, of all four, the first (more muscle) is by far the number reason people start lifting weights. But achieving a truly satisfying pump (as it’s referred to) has become the “goal before the goal”. Swollen muscles and fire-hose veins have become the badge of honor in the gym. It has become the marker to determine how effective your workout was!
So, where does Citrulline Malate fit in? Compelling research has recently revealed that the amino acid Citrulline Malate (2:1) could be the absolute best way to augment maximum blood flow to working muscles. Citrulline Malate (2:1) has a host of truly amazing benefits that go well beyond a really satisfying muscle pump as you’re walking away from your last lift.
What’s even more impressive is that you could reach your goals faster (like a leaner, more muscular frame) that can be sculpted through increased intensity, with less fatigue and greater blood flow into working muscles. This single, power-packed ingredient that has an impressive track record; both in the gym and in the research literature.
Check the label of pre-workouts like ALTRD State and you’re likely to see Citrulline Malate as a star performer – that’s why ALTRD State is loaded with 8.3 grams of it per scoop! Of the many different ingredients contained in a good training supplement, this high-performing amino is among the most important – so much so that many results-focused individuals have taken to using it as a standalone compound to significantly boost training effectiveness. Let’s take a detailed look at the reasons why you would also be wise to incorporate Citrulline Malate into your training plan of attack.
Once you read this, you’ll never want to train without it!
L-Citrulline is a non-proteinogenic (or “protein creating”) amino acid. This means it’s not incorporated biosynthetically into proteins during translation (i.e., it does not build muscle the same way certain other aminos do).
Instead, this non-essential amino acid, produced in the liver and intestines from arginine and glutamine (found in high amounts in watermelon), is one of three amino acids to make up the urea cycle. (The other two are L-Arginine and L-Ornithine). As part of the urea cycle, L-Citrulline’s main role is to prepare toxic compounds for elimination from the body which frees up energy for more ‘pressing’ matters…like training! L-Citrulline also possesses an impressive range of additional benefits that are specifically important for athletic performance and physique enhancement.
As a major part of the urea cycle, L-Citrulline helps to remove toxic fatigue-producing waste products, such as ammonia and nitrogen metabolites, from the body. Supplemental L-Citrulline improves this process to help sustain physical output and improve various aspects of training performance.
L-Citrulline stimulates the production of Nitric Oxide (NO), a molecule that is synthesized from molecular nitrogen and oxygen. Both play a major role in blood vessel dilation and, in turn, blood flow and metabolic waste product removal from muscle tissue. As a result, oxygen and nutrient delivery (including glucose) is improved – ultimately increasing muscle growth and performance as NO levels increase.
As an effective means to increasing blood flow, muscle energy metabolism and mitochondrial (energy organelle) respiration during exercise, NO has been shown to improve physical performance across multiple dimensions. As a potent endogenous (from outside the body) precursor of L-Arginine, a chemical component which increases the NO precursor enzyme NO synthase, L-Citrulline is arguably the fastest and most effective way to increase NO levels in the body.5, 12
In addition, whenever L-Arginine is converted to NO, L-Citrulline is produced as a by-product and recycled back to L-Arginine, where it is used to boost NO levels. This means the more L-Citrulline we have circulating at any given time, the more NO, and corresponding training benefits!
Given its status as a potent NO synthesizer, wouldn’t it be just as effective to supplement with L-Arginine? The short answer is NO. L-Citrulline is a far superior choice if your goal is to increase blood L-Arginine levels, go figure. Firstly, it’s more effectively absorbed compared to L-Arginine, when taken supplementally, and is rapidly removed from the body via the enzyme arginase in the gut.
Secondly, the comparatively minuscule amounts of L-Arginine that do survive the path of digestion through the small intestine and liver have a much shorter half-life than L-Citrulline and don’t circulate in the body for nearly as long.3 L-Citrulline, on the other hand, is taken directly to the bloodstream, with a longer half-life and is made available over a longer period of time.
Malate is an organic salt of malic acid found in fruits like apples and berries and is an important intermediary component in the tricarboxylic (TCA, or Krebs) cycle. The TCA is the energy system that uses oxygen to metabolize fat and yields the highest amount of energy (ATP) of the three systems.
Though Malate is believed to have specific standalone performance and health benefits, such as an ability to support the body to recycle exercise-generated lactic acid and use it for energy, more scientific evidence is needed to support its inclusion as a performance enhancer alone, however, when combined with L-Citrulline to make Citrulline Malate, the Malate version has been shown to enhance L-Citrullines effects as noted above.
But don’t be fooled with just regular Citrulline Malate. If the label doesn’t specify that the ratio is 2 parts Citrulline to 1 part Malate (or 2:1), it’s only 1:1, or worse! As good as Malate is, you want just enough of it to maximize the stability and absorption of the Citrulline. A 2:1 ratio is just that! Due to being the most heavily researched form of L-Citrulline, Citrulline Malate is considered to be the gold standard in L-Citrulline supplementation (though limited research makes a direct comparison between the two difficult).
1. Reduces Fatigue
Studies have shown Citrulline Malate to have impressive fatigue reducing properties, which bodes well for athletes wanting to extend training duration to get the most from their workouts.10, 17 Citrulline Malate has been shown to limit the effect of endotoxins (cell-associated bacterial toxins) on muscle fatigability.9 In addition, it also powers up the urea cycle to, among other functions, suck up the excess ammonia that would otherwise prematurely fatigue the working muscles.18
2. Promotes Aerobic Energy Production
Muscle tissue requires sufficient oxygen for energy production during aerobic training. As we have learned, greater NO levels lead to a greater supply of oxygen, which energizes the working muscles.2, 6, 11 Due to these positive changes in muscle metabolism, Citrulline Malate has, according to one study, been shown to produce a “34% increase in the rate of oxidative ATP production during exercise and a 20% increase in the rate of phosphocreatine recovery after exercise, indicating a larger contribution of oxidative ATP synthesis to energy production.”1
Such changes, along with Citrulline’s fatigue reducing benefits, also promote increased training volume (more reps and sets), a major indicator of steady muscle protein synthesis and subsequent muscle growth.
3. Increases Muscle Pump
The ability to achieve and sustain massive muscle pumps is yet another reason why many serious lifters add Citrulline Malate to their supplemental repertoire. Here, greater NO production resulting from increased L-Citrulline opens the blood vessels to allow maximum blood flow to the working muscles. This promotes the famed muscle pump, which, besides looking and feeling great, can lead to increased muscle gains.16
4. Increases Power Output and Muscle Endurance (in relation to resistance training performance)
Citrulline Malate has also been shown to increase muscle power, enabling greater effort to be applied to lifting heavier iron and exerting maximal effort in the gym or on the sports field.7, 8, 19, 20
Citrulline Malate has been shown to enhance muscle power output and endurance in alliance with a higher amount of oxidative energy turnover, a lower pH-to-power ratio and a lower ATP cost, which suggests that Citrulline Malate supplementation may have a beneficial impact on skeletal muscle metabolism. This also suggests increased contractile efficiency (or the ratio of mechanical work output to the total metabolic cost).2, 4
In another study, participants were “able to perform 53% more repetitions after ingesting Citrulline Malate compared to a placebo.”14
5. Decreases Perceived Rate of Exertion
Citrulline Malate ingestion can also make a workout feel easier than would normally be the case. Called perceived rate of exertion (PRE), this phenomenon is one indicator that the muscles are better able to handle, and benefit from, otherwise untenable levels of training stress. Citrulline Malate, as shown, can decrease fatigue and, with it, perceived rate of exertion by enhancing creatine phosphate re-synthesis, which leads to greater endurance benefits.8, 15
6. Decreases Muscle Soreness
Muscle soreness can be burdensome for many, especially as a hard training athlete. For some, it can be debilitating to the point of interfering with daily life. The ingestion of Citrulline Malate prior to training might be one way to address such soreness. In one study, post-training muscle soreness stemming from anaerobic exercise was reduced by 40% (24 hours after) and 42% (48 hours after) for subjects who took 8g of Citrulline Malate pre-training.14 In another study, Citrulline Malate supplements were shown to significantly reduce “post-exercise muscle soreness without affecting blood lactate levels [blood lactate levels being associated with muscle soreness].”15
How Much Citrulline Malate Should be Taken for Best Results?
Citrulline Malate requires no loading phase so 6-8 grams can be taken an hour before exercise to experience benefits. That is why ALTRD State features 8.3 grams per scoop. Though it’s important to keep in mind that 1.76g of Citrulline Malate is needed to about 1g of L-Citrulline (with the Malate version above, 1g is L-Citrulline and .75g is Malate). Therefore, if you’re accustomed to using L-Citrulline, you’ll need to bump up the dose to experience Citrulline Malate’s broader range of benefits.
Keep in mind also that Citrulline Malate is very tart in taste and can take a bit of getting used to. Here it can be taken as part of a great-tasting pre-workout or, for further benefits, extra Citrulline Malate can be added to an L-Citrulline containing pre-workout. Either way, Citrulline Malate is best taken on an empty stomach for optimal digestion and assimilation.
I’m “pumped” to take Citrulline Malate but is it Safe?
It is unlikely that taking Citrulline Malate in excess of the optimal doses outlined above will lead to unwanted side effects. In fact, of all the Citrulline studies that have been conducted over many years, no negative side effects have been experienced by individuals taking it in higher than normal doses. Therefore, Citrulline is considered to be one of the safest of all-natural performance enhancing substances, with doses of up to 15g posing no problem.13
- Bendahan, D. et al. (2002). Citrulline/malate promotes aerobic energy production in human exercising muscle.Br J Sports Med. Aug;36(4):282-9.
- Bailey, S. J. et al. (2015). L-citrulline supplementation improves O2 uptake kinetics and high-intensity exercise performance in humans. Journal of Applied Physiology, 119(4), 385-395.
- Botchlett, R. et al. (2019). l-Arginine and l-Citrulline in Sports Nutrition and Health. Nutrition and Enhanced Sports Performance, chapter 55, 645-652.
- Cunniffe, B. et al. (2014).The Acute Effects of Citrulline-Malate Supplementation on High Intensity Cycling Performance and Muscle Oxygenation: Medicine & Science in Sports & Exercise 551 May 28, 246:132
- Dhanakoti, S.N. et al. (1990). Renal arginine synthesis: studies in vitro and in vivo.Am J Physio 259: E437–E442.
- Dinenno, F.A. (2016). Skeletal muscle vasodilation during systemic hypoxia in humans. Journal of Applied Physiology, 120(2), 216-225.
- Glenn, J. M. et al. (2016). Acute citrulline-malate supplementation improves maximal strength and anaerobic power in female, masters athletes tennis players. European Journal of Sport Science, 1-9.
- Glenn, J.M. et al. (2015). Acute citrulline malate supplementation improves upper- and lower-body submaximal weightlifting exercise performance in resistance-trained females. Eur J Nutr. December.
- Goubel, F. et al. (1997). Citrulline malate limits increase in muscle fatigue induced by bacterial endotoxins. Can J Physiol Pharmacol. Mar;75(3):205-7.
- Hickner, R. C. et al. (2006). L-citrulline reduces time to exhaustion and insulin response to a graded exercise test. Medicine and Science in Sports and Exercise, 38(4), 660-666.
- Janeira, M. A. et al. (1998). Citrulline malate effects on the aerobic-anaerobic threshold and in post-exercise blood lactate recovery.Medicine and Science in Sports and Exercise, 30(5), Supplement abstract 880.
- McKinley-Barnard, S. et al. (2015). Combined L-citrulline and glutathione supplementation increases the concentration of markers indicative of nitric oxide synthesis. Journal of the International Society of Sports Nutrition, 12(1), 1-8.
- Moinard, C. et al. (2008). Dose-ranging effects of citrulline administration on plasma amino acids and hormonal patterns in healthy subjects: the Citrudose pharmacokinetic study. Br J Nutr. Apr;99(4):855-62.
- Pérez-Guisado, J. et al. (2010). Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. The Journal of Strength & Conditioning Research, 24(5), 1215-1222.
- Rhim, H. C. et al. (2020). Effect of citrulline on post-exercise rating of perceived exertion, muscle soreness, and blood lactate levels: A systematic review and meta-analysis Journal of Sport and Health Science February
- Schoenfeld, B. et al. (2014). The Muscle Pump: Potential Mechanisms and Applications for Enhancing Hypertrophic Adaptations. Strength and Conditioning Journal: – Volume 36 – Issue 3 – p 21-25
- Suzuki, T. et al. (2016). Oral L-citrulline supplementation enhances cycling time trial performance in healthy trained men: Double-blind randomized placebo-controlled 2-way crossover study. Journal of the International Society of Sports Nutrition, 13, 6. Retrieved from: https://jissn.biomedcentral.com/articles/10.1186/s12970-016-0117-z
- Wilkerson, J.E. et al. (1977). Exercise induced changes in blood ammonia levels in humans.Eur J Apple Physiol 37:255-26
- Wax, B. et al. (2015). Effects of supplemental citrulline malate ingestion during repeated bouts of lower-body exercise in advanced weightlifters. The Journal of Strength & Conditioning Research, 29(3), 786-792.
- Wax, B. et al. (2016). Effects of supplemental citrulline-malate ingestion on blood lactate, cardiovascular dynamics, and resistance exercise performance in trained males. J Diet Suppl. 13(3):269-282.