L-Citrulline
L-Citrulline is the pump amino acid of modern pre-workouts, raising arginine availability for nitric oxide production.
Cardio health
Workout performance
What it is
L-Citrulline is a non-protein amino acid, first isolated from watermelon, that the body converts to arginine, the substrate for nitric oxide synthesis. It has displaced arginine itself in most modern pre-workout briefs because oral citrulline raises blood arginine more effectively than oral arginine does.
Forms and sourcing
Two grades dominate: pure L-citrulline base, and citrulline malate, typically a 2:1 compound with malic acid that is the sports-nutrition standard. Both are fermentation-derived, vegan and freely soluble. Citrulline malate’s tart profile integrates well into fruit-flavoured pre-workout systems; the base form is blander for capsule use.
Benefits and evidence
Research on citrulline covers blood flow, exercise performance and reduced muscle soreness, with meta-analyses supporting modest benefits at meaningful doses: typically 6–8 g of citrulline malate or 3–4 g of base citrulline taken before training. Underdosed citrulline is one of the most common weaknesses we see in briefs arriving from other manufacturers, and dose honesty is central to a credible product.
Typical dosage and formats
Effective doses are gram-level, so powders and stick packs are the natural home; capsule delivery of a full dose takes six or more capsules and suits split-dose designs only. Citrulline is hygroscopic enough to need proper moisture control in powder blends, which our production standards handle routinely.
UK and EU regulatory position
L-Citrulline is an established food supplement ingredient in the UK and EU, permitted without novel food authorisation. There are no authorised EFSA health claims for citrulline, so pump or performance language cannot be attributed to the ingredient on-pack; compliant formulations typically carry claims through added B vitamins, or vitamin C for energy metabolism, while the citrulline dose speaks through the formula panel. Our artwork review keeps front-of-pack language compliant.
