L-Arginine
Conditionally essential cationic amino acid used in protein and urea-cycle metabolism and as the substrate for nitric-oxide synthases. Oral exposure is variable because intestinal and hepatic first-pass metabolism is extensive. Evidence for specific clinical uses does not imply general cardiovascular or athletic benefit.
Projected serum levels — 3k mg, once daily
Maintenance schedule: 3k mg once daily (oral).
Modeled steady state after ~1 days: peak ≈ 355 mg, trough ≈ 0.003 mg body load. Population-based estimate over 15 days for a 3k mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.
Key facts
- Category
- Amino Acid
- Route modeled
- Oral
- Model confidence
- inferred
- Half-life
- 1.3 h
- Common dose
- 3k mg
- Suggested maximum
- 30k mg/day
- Reference dose range
- 1.5k–30k mg (single dose)
- Suggested cadence
- once daily
- Validated against
- 10k mg oral — Cmax 34.9 mg/L at 1 h
Research behind this entry
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Pharmacokinetics of intravenous and oral L-arginine in normal volunteers
In a ten-person crossover study, 10 g oral L-arginine produced a mean total plasma peak of 50.0 mg/L at 1 hour from a 15.1 mg/L baseline. Absolute bioavailability averaged 21% but ranged from 5% to 50%, and the…
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L-arginine-induced vasodilation in healthy humans
Eight healthy men received placebo, 6 g oral, 6 g intravenous, and 30 g intravenous L-arginine. The 6 g oral condition had a calculated mean half-life of 79.5 minutes and highly variable bioavailability. Only the 30 g…
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The Potential Role of Arginine Supplements on Erectile Dysfunction
Systematic review and meta-analysis included ten randomized trials and 540 men with mild-to-moderate erectile dysfunction. Doses of 1.5-5 g improved several erectile-function outcomes versus placebo or no treatment, but…
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Dietary Arginine and Citrulline Supplements for Cardiovascular Health and Athletic Performance
Narrative review found mixed, context-dependent results across vascular and exercise studies. Oral arginine often showed limited performance benefit because of first-pass metabolism, while citrulline more reliably…
6 published studies referenced in the app, each with a plain-language summary.