Citrulline malate is a popular pre-workout ingredient — but does it live up to the hype? Here’s what the research actually shows.
The bottom line
The evidence suggests citrulline malate may provide a small boost to certain types of resistance-training performance — particularly at moderate-to-high reps pushed toward fatigue — and may reduce how hard exercise feels in some situations. What it doesn’t have strong evidence for is directly building muscle or increasing maximal strength. Useful edge? Potentially. Magic muscle-builder? No.
You may squeeze out a few extra reps
Small but real effectA 2021 systematic review and meta-analysis of eight studies (137 participants) found taking 6–8 g of citrulline malate around 40–60 minutes before resistance exercise increased repetitions by about 6.4% versus placebo — an average of roughly three additional reps across the tested protocols, with a stronger signal for lower-body than upper-body work. The overall effect is small, and the latest reviews still characterise the performance benefit as small and uncertain rather than dramatic. In gym terms: a potentially useful edge, not a cheat code.
It may make hard training feel slightly easier
Promising but inconsistentA systematic review of 13 randomised controlled trials found citrulline supplementation significantly reduced post-exercise ratings of perceived exertion, and reduced muscle soreness at 24 hours — though the 48-hour result wasn’t statistically significant and there was no meaningful effect at 72 hours. So the “less sore tomorrow” claim has some support, with a giant asterisk: promising but inconsistent, not a recovery guarantee.
What about strength?
No clear benefitHere the hype gets ahead of the science. A systematic review and meta-analysis in resistance-trained adults found no significant overall improvement in muscle strength from citrulline malate, for either upper- or lower-body strength. If your goal is a bigger one-rep max, citrulline malate shouldn’t be your first port of call.
Why does citrulline malate work?
L-citrulline is an amino acid naturally produced by the body and found in foods like watermelon. Once consumed, much of it is converted by the kidneys into L-arginine, which is involved in producing nitric oxide (NO) — a signalling molecule that helps regulate blood-vessel dilation. That gives a plausible mechanism (more citrulline → more circulating arginine → potentially greater nitric-oxide availability). But the mechanism making sense doesn’t mean the performance effect is large: evidence that citrulline consistently produces meaningful improvements in muscle blood flow or performance is mixed, and the NIH describes the evidence as limited.
Citrulline malate vs L-citrulline
Worth understanding the labelThese aren’t the same. L-citrulline is the amino acid itself. Citrulline malate combines L-citrulline with malate (the salt of malic acid), most research using a 2:1 ratio. That matters when reading a label: an 8 g serving of citrulline malate isn’t 8 g of L-citrulline — at a true 2:1 ratio, 8 g provides roughly 5.3 g of citrulline, with the rest coming from malate. So don’t compare an 8 g citrulline malate serving directly with an 8 g L-citrulline serving.
Can citrulline malate build muscle?
Not provenHere we’d pump the brakes. There isn’t convincing evidence that citrulline malate directly increases long-term muscle growth. One small pilot (just eight participants) found citrulline increased mixed-muscle protein synthesis after three days of a low-protein diet — but that’s an acute measure, not proof of long-term muscle gain. If citrulline helps you complete a little more quality training volume, that could contribute to better adaptations over time — but that’s a hypothesis, not proof. For hypertrophy, the priorities remain progressive training, adequate protein and calories, recovery and consistency.
What dose should you take?
Research commonly uses 6–8 g before exercise, with the 2021 meta-analysis finding a small benefit from 6–8 g taken about 40–60 minutes before training. Newer reviews note there isn’t enough evidence to establish one universally optimal dose or timing — so 6–8 g is a commonly studied amount, not a proven “optimal” one. And check the citrulline-to-malate ratio on the label.
Safety note
Short-term studies report relatively few adverse effects, though gastrointestinal discomfort can occur — one well-known bench-press study reported stomach discomfort in about 15% of participants after an 8 g dose. Long-term safety isn’t well established. Athletes subject to anti-doping rules should consider supplement quality and contamination risk.
Common questions
Citrulline Malate FAQ
What is citrulline malate good for?
Its best-supported benefit is a small improvement in resistance-exercise performance — helping you squeeze out a few extra reps in demanding sets — and it may reduce perceived exertion and short-term soreness.
Does citrulline malate actually work?
For a modest rep boost and reduced perceived effort, there’s supportive evidence, though the effect is small. For building muscle or increasing maximal strength, the evidence doesn’t currently support it.
How much citrulline malate should I take?
Research commonly uses 6–8 g taken about 40–60 minutes before training, but an optimal dose isn’t firmly established. Check the citrulline-to-malate ratio, as an 8 g serving isn’t 8 g of citrulline.
What’s the difference between citrulline malate and L-citrulline?
L-citrulline is the amino acid; citrulline malate pairs it with malate, usually 2:1. So the same gram amount delivers less pure citrulline in the malate form.
Is citrulline malate safe?
Short-term use is generally well tolerated, though some people get stomach discomfort at higher doses. Long-term safety isn’t well established. Check with a healthcare professional if you have a condition or take medication.
If you’re interested, feel free to explore our recommended range of high-quality superfood supplements here.
Sources
- Vårvik FT, et al. Acute effect of citrulline malate on repetition performance during strength training: systematic review and meta-analysis. Int J Sport Nutr Exerc Metab, 2021. — reps/performance.
- Rhim HC, et al. Effect of citrulline on post-exercise rating of perceived exertion, muscle soreness and blood lactate: systematic review and meta-analysis. J Sport Health Sci, 2020. — perceived exertion/soreness.
- Trexler ET, et al. Citrulline malate and resistance-exercise strength (meta-analysis). — strength.
- Pérez-Guisado J, Jakeman PM. Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. J Strength Cond Res, 2010. — the 8 g bench-press study.
- National Institutes of Health, Office of Dietary Supplements — dietary supplements for exercise and athletic performance (citrulline). — overall evidence.
This article is for general information only and is not medical advice. Australian Herbal products are not intended to diagnose, treat, cure or prevent any disease. Speak with a qualified healthcare professional before starting any supplement, particularly if you are pregnant, breastfeeding, taking medication or managing a health condition.