Guide
L-citrulline vs citrulline malate: what's actually different
L-citrulline is the free amino acid; citrulline malate binds it to malic acid, usually in a 2:1 ratio by weight, so roughly 70% of a citrulline malate serving is citrulline. The two trials that put the forms head-to-head, at doses matched for actual citrulline content, found no meaningful difference between them.
L-citrulline is the free amino acid on its own; citrulline malate binds it to malic acid, usually in a 2:1 ratio by weight, so roughly 70% of a citrulline malate serving is citrulline and the rest is malate. The two head-to-head trials that have tested them directly found no meaningful performance difference between the forms.
What each one actually is
| Form | What it is | What a gram provides |
|---|---|---|
| L-citrulline | The free amino acid, unbound | 1 g = 1 g of citrulline |
| Citrulline DL-malate | Citrulline bound to malic acid, commonly 2:1 by weight | Roughly 0.7 g of citrulline per gram — the rest is malate |
The "DL" refers to the malic acid half of the compound, not the citrulline — malic acid is commonly sold in its racemic (mixed D- and L-) form, while the citrulline portion is always the L-configuration. Because a citrulline malate label's gram figure includes the malate weight, an 8 g dose of citrulline malate provides meaningfully less actual citrulline than an 8 g dose of plain L-citrulline. A label that states only "8 g Citrulline Malate" without the ratio makes that math impossible to do.
What the head-to-head trials found
Two trials have put the two forms against each other directly. A 2025 randomized, double-blind trial gave 33 resistance-trained men either 8 g/day of plain L-citrulline or 12 g/day of citrulline DL-malate — doses chosen to provide a comparable actual-citrulline amount — alongside a 6-week resistance-training program. Upper-body muscular endurance and a blood marker of nitric-oxide production improved similarly in both groups compared with placebo, with no meaningful difference between the two forms on any outcome measured.
A 2024 randomized, double-blind, crossover trial gave 43 young, trained men and women a single 5.3 g dose of plain L-citrulline, the same 5.3 g combined with 2.7 g of malic acid (as citrulline malate), or a placebo, 45 minutes before testing. Neither citrulline form improved maximal strength, jump performance, or strength-endurance in the squat or bench press compared with placebo — a null result for both forms, not just a tie between them.
Between those two trials, the honest summary is: when a difference between the forms has been tested for directly, none has shown up. Whether citrulline works better than placebo at all depends on the specific outcome and trial — see L-citrulline benefits: what the research does and doesn't show.
Where citrulline malate's extra research comes from
Citrulline malate has more of its own dedicated research history than plain L-citrulline, partly because it was the form used in some of the earliest bench-press and muscle-soreness trials — including a 2010 crossover trial in 41 men that found an 8 g single dose of citrulline malate increased bench-press repetitions as sets went on and reduced next-day muscle soreness by about 40%, versus placebo. That's a real finding for citrulline malate specifically, but the 2025 head-to-head trial above suggests plain L-citrulline produces a similar effect at a dose providing a similar amount of actual citrulline — the malic acid itself doesn't appear to be doing separate work.
Digestive tolerance
The 2010 citrulline malate trial reported stomach discomfort in about 15% of participants after a single 8 g dose. A separate dose-finding study using plain L-citrulline at doses up to 15 g reported no side effects at all. Whether that difference comes from the malate portion, the dose, or taking it close to intense exercise isn't something either trial was designed to isolate.
Questions people ask
Is L-citrulline the same as citrulline malate?
No — citrulline malate is citrulline bound to malic acid, commonly in a 2:1 ratio by weight, so a given gram figure on a citrulline malate label contains less actual citrulline than the same gram figure of plain L-citrulline.
What is L-citrulline malate 2:1?
It describes the ratio of citrulline to malic acid by weight — two parts citrulline to one part malic acid, meaning about 70% of the total weight is citrulline.
Which is better, L-citrulline or citrulline malate?
The two trials that tested them head-to-head, at doses matched for actual citrulline content, found no meaningful difference between the forms. Choosing between them is mostly a dosing-math and, for some people, digestive-tolerance question, not a question of one being more effective.
Why take citrulline malate instead of plain L-citrulline?
Some of citrulline's earlier exercise research used the malate form, so it has a longer specific research history for outcomes like bench-press endurance. The head-to-head trials above suggest plain L-citrulline performs similarly at a comparable actual-citrulline dose — the choice comes down to label math and price per gram of actual citrulline rather than an established performance edge.
Which form did the small sexual-health trial use?
The one small trial with a positive finding used plain L-citrulline (1.5 g/day), not the malate form — see L-citrulline benefits: what the research does and doesn't show for that trial's real limits.
How to choose between them
How to choose a good L-citrulline covers the full checklist — form, disclosed malate ratio, stated amount versus research doses, other ingredients, safety disclosure, price per serving and testing.
Related reading: what is L-citrulline? and how much L-citrulline should you take a day?.
Sources
- Citrulline: pharmacological perspectives and its role as an emerging biomarker in future A 2013 pharmacology review describes L-citrulline as a naturally occurring amino acid and urea-cycle intermediate that the body converts to arginine more efficiently than arginine converts to itself, and lists the range of conditions where its supplementation is being researched, from erectile dysfunction to rare urea cycle disorders.
- Changes in resistance training performance, rating of perceived exertion, and blood biomarkers after six weeks of supplementation with L-citrulline vs. L-citrulline DL-malate in resistance-trained men: a double-blind placebo-controlled trial A 2025 six-week trial in 33 resistance-trained men found that daily L-citrulline (8 g) or citrulline malate (12 g) improved upper-body muscular endurance more than placebo and raised a blood marker of nitric-oxide production, with no meaningful difference between the two citrulline forms on any measured outcome.
- Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness A 2010 crossover trial in 41 men found a single 8 g dose of citrulline malate before a bench-press session increased the number of repetitions completed as the sets went on, and reduced next-day and two-day muscle soreness by about 40%, compared with placebo; about 15% of participants reported stomach discomfort.
- Dose-ranging effects of citrulline administration on plasma amino acids and hormonal patterns in healthy subjects: the Citrudose pharmacokinetic study A 2008 dose-escalation study gave 8 healthy men single oral doses of citrulline from 2 g up to 15 g and found no side effects at any dose, but at the two highest doses the expected rise in blood arginine was smaller than predicted — the researchers think the kidneys' conversion of citrulline into arginine becomes saturated at higher doses.
- Malate or Not? Acute Effects of L-Citrulline Versus Citrulline Malate on Neuromuscular Performance in Young, Trained Adults: A Randomized, Double-Blind, Placebo-Controlled Crossover Trial A 2024 randomized, double-blind, placebo-controlled crossover trial in 43 young, trained men and women found that neither a single 5.3 g dose of plain L-citrulline nor the same amount combined with malic acid as citrulline malate improved maximal strength, jump performance, or strength-endurance in the squat or bench press, compared with placebo.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.