Comparison
Creatine vs L-Citrulline
Creatine
The most-studied performance supplement in history, now well-evidenced as a cognitive enhancer in its own right. The brain consumes about 20% of resting metabolic rate, and creatine buffers ATP at the use site for fast regeneration — especially valuable under mental fatigue and sleep deprivation. Vegetarians benefit most because dietary creatine comes from animal flesh.
L-Citrulline
Amino acid converted to L-arginine, raising nitric oxide. Used for vasodilation, athletic performance, and ED.
| Field | Creatine | L-Citrulline |
|---|---|---|
| Category | amino-acid | amino-acid |
| Dose range | 3000–5000mg | 3000–8000mg |
| Half-life | 3h | — |
| Onset | — | — |
| Evidence | EVIDENCEA | EVIDENCEA |
| Safety | ●●●●● | ●●●●● |
| Legal (US) | USOTC | USOTC |
| PubMed refs | 1800 | 1100 |
The comparison in plain English
Auto-generated from dataCreatine and L-Citrulline are both in the amino-acid category respectively. Creatine The most-studied performance supplement in history, now well-evidenced as a cognitive enhancer in its own right. L-Citrulline Amino acid converted to L-arginine, raising nitric oxide.
Bottom line
Creatine (evidence A, safety 5/5) matches the evidence base of L-Citrulline (evidence A, safety 5/5). Creatine has the slightly cleaner safety profile. For users new to either, the higher-evidence option is the safer first try.
Choose Creatine if
Creatine is the better fit when your goal aligns with its mechanism (Phosphorylated by creatine kinase to phosphocreatine, the fastest available ATP buffer in the cell (millisecond timescale)) and the dose range (3000–5000mg) suits your protocol. Half-life is 3h.
Choose L-Citrulline if
L-Citrulline is the better fit when your goal aligns with its mechanism (Citrulline bypasses arginine's poor oral bioavailability — it is absorbed efficiently from the gut, then converted to arginine in the kidneys, raising plasma arginine and nitric oxide more reliably than oral arginine itself) and the dose range (3000–8000mg) suits your protocol. Half-life is —h.