Citrulline malate is a fixture of pre-workout and intra-workout products, usually dosed in whole grams rather than milligrams. Brands abroad ask for it by name, often expecting the strong claims common in sports-nutrition marketing.
The research is more careful than the marketing. This guide covers what recent systematic reviews and meta-analyses actually found for exercise performance and post-exercise soreness, how citrulline is formulated as a food or drink, and what to fix before asking a Japanese factory for a quotation.
Health supplements are foods, not medicines, and are not a substitute for medical treatment. Nothing here is a claim that any product prevents, treats or cures a disease.
💬 Planning a citrulline product made in Japan? We check the full formula against Japanese food law first. See Japan-made supplement OEM.
What the research shows
A 2026 meta-analysis of 30 trials found only a small overall improvement in exercise performance, and earlier, smaller reviews disagree on whether citrulline helps aerobic performance or post-exercise soreness.
| Study | Design | Reported result |
|---|---|---|
| Three-level meta-analysis, Nutrients 2026, 18(12):1881 (PMID 42356270) | 30 randomised controlled trials, 138 effect sizes, 644 participants; citrulline malate and exercise performance or perceived exertion | Small overall improvement in exercise performance (g = 0.16, p = 0.01), but wide prediction intervals and GRADE certainty rated low to very low; no significant effect on perceived exertion |
| Meta-analysis, Nutrients 2022, 14(17):3479 (PMID 36079738) | 10 randomised trials of citrulline supplementation and aerobic performance, oxygen-uptake kinetics, perceived exertion and blood lactate | No significant benefit for aerobic performance, oxygen-uptake kinetics, perceived exertion or lactate |
| Meta-analysis, Journal of Sport and Health Science 2020, 9(6):553–561 (PMID 33308806) | 13 randomised trials, 206 participants; citrulline or citrulline malate (most often 8 g) before exercise, measuring perceived exertion, muscle soreness and blood lactate | Reduced perceived exertion (p = 0.03) and muscle soreness at 24 hours after exercise (p = 0.04); no significant effect on soreness at 48 hours (p = 0.25) or 72 hours (p = 0.62), or on blood lactate |
Three points worth keeping in view:
- The reviews disagree with each other. The 2022 review found no aerobic benefit at all; the 2026 review found a small one. Both are legitimate readings of a small, heterogeneous evidence base.
- Certainty is low. The largest and most recent analysis rated its own evidence as low to very low certainty, with wide prediction intervals, and said reliable dosing, timing and target populations are not yet established.
- Soreness relief did not last. In the 2020 review, the reduction in muscle soreness was significant at 24 hours but not at 48 or 72 hours.
Checked against the published abstracts on 12 October 2026.
What Japanese products say
Citrulline was first identified in watermelon by Japanese chemists in 1914, and a Japanese Foods with Function Claims notification for it covers a narrower function than the exercise-performance research abroad.
The amino acid takes its name from Citrullus, the Latin word for watermelon: Japanese researchers first isolated it from watermelon juice in 1914, and a Japanese chemist gave it its name and structure in 1930. It is a long-standing, non-promotional piece of the ingredient’s history rather than a product claim.
One product notified under Japan’s Foods with Function Claims system uses L-citrulline (800 mg per daily serving) as its functional ingredient, and its notified function concerns maintaining the temperature of the hands when they feel cold — not exercise performance or muscle recovery. That is a narrower use than the sports-nutrition research discussed above, and a useful reminder that a Japanese notification is a claim about one specific, evidenced function, not a general endorsement of the ingredient. L-citrulline itself is otherwise used as an ordinary ingredient in Japanese foods and supplements.
💬 Need an evidence summary for your regulatory adviser that separates the exercise-performance research from Japan’s notified functions? We prepare it with the manufacturing documents. Tell us your market.
Wording that stays on safe ground
Describe citrulline by what has actually been studied for exercise, not by mechanisms the studies above did not measure.
| Safer wording | Wording to avoid |
|---|---|
| ”Studied for exercise performance and post-exercise perceived exertion” | Blood-pressure claims, or any claim about blood flow to a sexual organ or erectile function |
| ”Contains citrulline malate” with the amount per serving | ”Boosts circulation” or vasodilation claims tied to a specific health outcome |
| Naming the review you cite, including its small effect size and low certainty | ”Clinically proven” without naming the study and its limits |
How citrulline is formulated
Effective doses are measured in whole grams, so the practical choice is between a powder stick or drink and a multi-capsule serving.
| Dosage form | Why brands choose it | What to weigh up |
|---|---|---|
| Powder stick or drink mix | Delivers a 6–8 g dose in one serving; the standard pre-workout format | Citrulline malate is tart from the malic acid; flavouring and sweetening need testing |
| Capsule | Convenient, no taste to mask | A full dose needs several large capsules, which raises cost and pack size |
| Tablet | Familiar format for some markets | Same gram-dose problem as capsules, plus compression challenges at this dose |
| Combined training blend (with other amino acids) | Matches how citrulline is used in practice | Every companion ingredient needs its own check against Japanese food law |
Decisions that shape the specification:
- L-citrulline or citrulline malate. Citrulline malate combines the amino acid with malic acid, commonly in a fixed ratio; the malate portion adds bulk and a sour taste but is the form most studies above actually tested. Plain L-citrulline is more concentrated per gram but has less of this specific research behind it.
- Dose per serving. Match the amount to the study you intend to cite — 8 g of citrulline malate was the most common dose in the 2020 review above.
- Solubility and taste. Citrulline is water-soluble, which suits a powder stick or ready-to-drink format, but the sourness of the malate form needs flavour work, especially at gram-level doses.
- Companion ingredients. Citrulline is often combined with other amino acids or training ingredients. Each one needs its own check against Japanese food law before it goes into the formula.
The check that comes first
Every ingredient must be permitted in foods in Japan, or a Japanese factory cannot make the product.
Citrulline itself is widely used in Japanese foods and supplements. Training-formula partners are where problems usually turn up: some ingredients sold freely as sports nutrition elsewhere are treated as medicines in Japan. See the Japan-made supplement OEM page, and compare with our creatine and HMB guides if you are building a combined training formula.
Before you ask for a quotation
A factory can quote accurately once the form, the dose, the companions and the packaging are fixed.
- L-citrulline or citrulline malate, and the ratio if malate
- Dose per serving and servings per pack
- Dosage form, and flavour if a drink or powder stick
- Companion ingredients and their amounts
- Packaging
- Countries you will sell in, and first order and annual volume
💬 Ready to design a Japan-made citrulline product? Send us the concept — form, dose, companion ingredients and the countries you will sell in.
Frequently asked questions
1. Does citrulline actually improve exercise performance?
A 2026 meta-analysis of 30 trials found a small overall improvement, but rated its own evidence as low to very low certainty with wide prediction intervals. An earlier 2022 review of 10 trials found no significant benefit for aerobic performance at all. Describe citrulline as studied for exercise performance, not as a proven performance booster.
2. Does citrulline malate reduce muscle soreness after training?
A 2020 review of 13 trials found a significant reduction in soreness at 24 hours after exercise, but not at 48 or 72 hours. Any soreness claim should reflect that short window.
3. Should I use L-citrulline or citrulline malate?
Citrulline malate is the form most of the exercise studies above actually tested, usually around 8 g per serving. Plain L-citrulline is more concentrated by weight but has less of this specific research behind it.
4. What dose do the studies use?
Most commonly around 6–8 g of citrulline malate per serving, taken before exercise. Match your specification to the study you plan to cite.
5. What does Japan’s Foods with Function Claims system say about citrulline?
One notified product uses L-citrulline as its functional ingredient, and its function concerns maintaining the temperature of the hands when they feel cold, not exercise performance. That notification does not extend to sports-performance claims, and each product needs its own notification and evidence.
Sources: “Effects of Citrulline Malate Supplementation on Exercise Performance: A Systematic Review and Three-Level Meta-Analysis”, Nutrients 2026, 18(12):1881 (PMID 42356270); “Effects of Citrulline Supplementation on Different Aerobic Exercise Performance Outcomes: A Systematic Review and Meta-Analysis”, Nutrients 2022, 14(17):3479 (PMID 36079738); “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 2020, 9(6):553–561 (PMID 33308806); Koga Y, Ōtake R (1914) and Wada M (1930) on the isolation and naming of citrulline from watermelon; product information for one notified Food with Function Claims containing L-citrulline. Checked on 12 October 2026.