Nitric oxide precursors are among the most commonly used supplements on the market, mostly because they’re a staple in just about every pre-workout product. Arginine was the first nitric oxide precursor to become popular, but it has largely fallen out of favor due to its poor bioavailability.
Citrulline malate (CitMal) is one of the supplements that has taken the place of arginine in pre-workout supplements, as it can effectively increase nitric oxide production, which can favorably impact blood flow, exercise efficiency, and the contractile function of muscle.
This meta-analysis gathered up all the studies assessing the acute impact of citrulline malate supplementation on strength endurance (repetitions to failure during resistance exercise). Compared to placebo, CitMal led to trivial-to-small positive effects on lower-body, upper-body, and overall strength, with the overall effect being statistically significant.
These results are quite similar to the findings of our very own Eric Trexler, who published a 2019 meta-analysis more broadly assessing the effects of citrulline on a variety of strength and power outcomes. While this body of research isn’t particularly large, the data available suggest that 6-8g of CitMal (preferably in a 2:1 Cit:Mal ratio) can enhance strength endurance when taken about an hour before exercise.
There are also a couple of nice bonus features to acknowledge: CitMal is pretty affordable in comparison to many other supplements, and also has a sour taste that pairs very well with just about any sweet beverage or water enhancer.
If you want to read more about citrulline and related supplements, check out our article: Are Nitric Oxide Supplements Beneficial For Strength and Hypertrophy?