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Citrulline · Moderate evidence
What citrulline is for and how much to take
The short answer. Citrulline is the arginine precursor that does survive the liver, which is why it raises nitric oxide better than taking arginine directly. Performance studies use 6-8 g of citrulline malate per serving, and what they measure is a few more reps in sets to failure and slightly less soreness. It is a small effect and not entirely consistent, and it depends on a dose most pre-workouts do not contain.
There are studies in favour, but few, with small samples or measuring markers instead of outcomes. No figure on this page is attributed to a specific product: the effect belongs to the ingredient and every number carries its source next to it.
01 What it does and how much
Each row is a measured effect, with the figure the study gives and the source number. Where the evidence gives no figure, the column says so instead of making up a percentage.
| Effect | How much | Detail |
|---|---|---|
| Dose per serving | 6 to 8 g of citrulline malate | It is the range of the performance studies. Almost all pre-workouts on the market stop at 2-4 g, which is half a dose or less. [1] |
| Reps in sets to failure | a few more | The most repeated effect. It is real but modest, and it does not show up in every study or every exercise. [2] |
| Soreness at 24-48 h | slightly less | Measured with perceived pain scales, which is subjective data. It is counted for what it is: an effect reported by the subject, not a biopsy. [2] |
| Against arginine | raises blood arginine more | It sounds like a paradox and is not: oral arginine is broken down by the liver before reaching the circulation, and citrulline does not go that way. [1] |
02 How to take it
- Dose. 6 to 8 g of citrulline malate, or 3 to 5 g if the product is pure citrulline.
- When. 30 to 60 minutes before training.
- How long before you notice it. It is an acute effect: you look for it in that day’s session.
Details that change the result
- Citrulline malate 2:1 means two parts citrulline to one part malate: 8 g contains about 5.3 g of citrulline. If the tub does not state the ratio, you do not know what you are taking.
- Pure citrulline delivers more per gram than malate, so the equivalent dose is lower.
- It is the ingredient most often underdosed in pre-workouts: check the milligrams per serving before the list of names.
- It is not a stimulant and you will not feel it like caffeine. If you expect a buzz, a different ingredient provides that.
03 When it makes sense and when it does not
Worth it if
- Hypertrophy training with sets to failure and short rests.
- You want a pre-workout effect without caffeine, because of timing or tolerance.
- You already have creatine, protein and sleep covered and want to fine-tune.
Not worth it if
- Looking for maximal strength: that is not where its effect is measured.
- If the product carries 2 g per serving: reaching a useful dose would take three or four servings.
- As a caffeine substitute when what you want is a buzz.
04 Sources
Every figure above comes from here. They are position stands from scientific societies, meta-analyses and peer-reviewed reviews: if a claim cannot hang from one of these lines, it is not on the page. References are cited in their original form.
- Kerksick CM et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr. 2018;15:38. Citrulina malato en el rango de 6-8 g por toma en los estudios de rendimiento. doi:10.1186/s12970-018-0242-y
- Perez-Guisado J, Jakeman PM. Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. J Strength Cond Res. 2010;24(5):1215-1222. doi:10.1519/JSC.0b013e3181cb28e0
This is not medical advice. It is what some studies say about an ingredient, not a protocol for you. With an illness, medication or pregnancy involved, the decision belongs to a healthcare professional who knows you.
Questions about citrulline
Answered with the data on this page
- How much citrulline should you take before training?
- Performance studies use 6-8 g of citrulline malate about 30-60 minutes before. If the product is pure citrulline, the equivalent amount is lower, 3 to 5 g, because malate is not citrulline. Most commercial pre-workouts carry well below that dose.
- Which is better, citrulline or arginine?
- Citrulline, for a counter-intuitive reason: arginine taken by mouth is broken down by the gut and liver before reaching the blood, whereas citrulline does get there and is converted into arginine. To raise nitric oxide, taking citrulline raises blood arginine more than taking arginine.
- What does citrulline malate 2:1 mean?
- That out of every three parts, two are citrulline and one is malic acid. An 8 g serving of 2:1 citrulline malate contains about 5.3 g of citrulline. It is the figure to check when comparing two products: a 1:1 at the same price carries considerably less citrulline.
- Does citrulline give you the gym pump?
- It increases blood flow via nitric oxide, and that feeling is real during the session. What has not been shown is that the pump translates into more muscle over time. The effect that is measured in studies is a few more reps and slightly less soreness.
And now, which to buy
Prices, kept apart from the evidence
This page explains what citrulline does and deliberately names no brand. The comparison is the other half: 42 products from 10 stores from €29.16 per kg, sorted by price and by how verifiable their certification is.
Other guides
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