L-Citrulline
Also known as: citrulline, free-form citrulline, Kyowa citrulline
A non-protein amino acid that the kidneys convert to arginine, raising plasma arginine more efficiently than oral arginine itself. It is the leading nitric-oxide precursor in pre-workout and pump products and is studied for endurance performance, muscle soreness, and blood flow. Pure L-citrulline delivers more citrulline per gram than citrulline malate.
Research summary
Bypasses first-pass arginine metabolism to raise systemic arginine and nitric oxide production, supporting vasodilation.
Dosage
Daily amounts, of compound.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 3 g | 6–8 g | 10 g | — |
Performance studies mostly use 3–8 g taken about 60 minutes before exercise; 6–8 g is the pre-workout standard. Doses up to 10 g/day have been used in trials. Some protocols dose daily for a week or more before the performance test rather than acutely.
Source material: fermentation-derived
Forms of Citrulline
| Form | Typical dose | Element % | Formats | Price |
|---|---|---|---|---|
| L-Citrulline | 6–8 g | — | Powder, Capsule, Tablet | low |
| Citrulline Malate (2:1) | 6–8 g | — | Powder, Capsule, Tablet | low |
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Gram-scale dose: a 6 g serving is roughly 8–9 size-00 capsules, so powder is the realistic format. Mild, slightly sour taste that masks easily.
Formulation notes
Stacked with creatine, beta-alanine, and caffeine in pre-workouts; with beetroot or nitrates for additive nitric-oxide support.
Sources
Related ingredients
Beta-Alanine
Sports performanceA non-essential amino acid that combines with histidine to form carnosine, the main intramuscular buffer of hydrogen ions during intense exercise.
Typical: 3.2–6.4 g
BCAA 2:1:1 (Leucine, Isoleucine, Valine)
Sports performanceA blend of the three branched-chain amino acids, most often at a 2:1:1 ratio of leucine to isoleucine to valine, that has been a staple of intra-workout drinks for decades.
Typical: 5–10 g
Citrulline Malate (2:1)
Sports performanceA salt of citrulline and malic acid, most often in a 2:1 ratio, that has been the traditional form in pre-workouts.
Typical: 6–8 g
Taurine
Amino acidA sulfur-containing amino acid abundant in muscle, heart, and brain, and a familiar ingredient in energy drinks and pre-workouts.
Typical: 1–3 g
Potassium Chloride
MineralThe most concentrated common potassium source at about 52% elemental potassium, and the salt used in most blood-pressure trials of potassium supplementation.
Typical: 99–500 mg