Citrulline is an amino acid that the body turns into arginine and then nitric oxide, which widens blood vessels. It is sold for workouts and blood pressure.
Calculator Official intake Study doses Best form Safety Sources
Citrulline is not an essential nutrient, so there is no official daily intake. Only study doses are shown.
These are doses tested in research, not personal advice. Some exceed the upper limit because they were short courses or given under medical care.
4-8 g a day, for a few days only
Meta-analysis of 12 studies (198 people): mostly 8 g citrulline malate (6 to 12 g, about 4 to 8 g citrulline) about 60 minutes before exercise gave a small but significant performance benefit, mainly for strength.
3-9 g a day
Meta-analysis of 8 trials using 3 to 9 g L-citrulline a day: systolic pressure fell about 4 mmHg. Diastolic pressure only fell significantly at 6 g a day or more.
Practical pick
L-citrulline (g)
Why: Pure L-citrulline gives the most citrulline per gram, so dosing is simple.
Alternatives: Citrulline malate (2:1) is what most workout studies used; take about 1.5 times as many grams to match.
Study doses below are in grams of L-citrulline. 8 g of 2:1 citrulline malate gives about 5.3 g citrulline.
Watermelon (especially the rind), cucumber, melons.
May add to the effect of blood pressure medicines, nitrates and erectile dysfunction drugs (sildenafil and similar).
Generally well tolerated; large doses can upset the stomach.
Pregnant, breastfeeding, on medication, or managing a health condition? Check with a doctor or pharmacist before starting a supplement.
Values checked: November 12, 2026.
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