Science Library

Citrulline

Moderate evidence

L-citrulline / citrulline malate

Moderate evidenceStrengthRecovery

Dose

8 g CitMal

Timing

40-60 min pre

Best for

Reps to failure

Aerobic?

No real benefit

Does it work?

-A little, for lifting. At a proper pre-workout dose, citrulline reliably squeezes out about 2-3 extra reps before failure and may take the edge off soreness, but the effect is small and it does nothing useful for aerobic or endurance work. Worth a try if you train to failure and want a cheap, safe edge; skip it if you're chasing cardio or a big "pump" payoff.

How much · when

-Take 8 g citrulline malate (or ~3-6 g pure L-citrulline) 40-60 minutes before training.
-Best on high-volume, train-to-failure sets — the effect shows up as a couple extra reps, mainly on lower-body lifts.
-Take it consistently on training days; there's no need to load or cycle it.
-Stacks fine with caffeine and creatine if you already use them.

The catch

-The benefit is small — meta-analysis puts it at ~3 extra reps (6.4%) and an effect size of ~0.2. Real, but not a game-changer.
-Most studies use citrulline malate; the 'malate' is filler, so you're paying for a blend. Plain L-citrulline at ~3-6 g is the cheaper active dose.
-Marketed for the 'pump' and endurance, but the evidence for aerobic performance is weak and inconsistent.

Safety

-Very safe and well tolerated even at 8 g; the most common complaint is mild stomach upset.
-If you take nitrates or blood-pressure/ED medication, check with a doctor — citrulline mildly raises nitric oxide.

Key research

Supplements

CreatineStrong Beta-alanineModerate

Exercises

Back Squat

Squat

Barbell Bench Press

Horizontal press

Educational information, not medical advice. Talk to a healthcare professional before starting a supplement — especially if you're pregnant, nursing, or managing a health condition.

Reviewed Jun 2026

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