L-citrulline,
does it really help with Improvement of erection hardness and sexual function in mild erectile dysfunction?
research showsDirect evidence for standalone L-citrulline centers on 24 men with mild erectile dysfunction who received placebo for one month followed by 1.5 g/day for one month in a single-blind sequential pilot. Improvement in erection hardness score from 3 to 4 occurred in 8.3% during placebo and 50% during L-citrulline, but this was not a randomized parallel trial and the sample was very small. Results from combinations containing Pycnogenol, arginine, and other ingredients cannot be attributed to citrulline alone, so the rating is C.
ads claimMarketing may present nitric-oxide production and blood flow as equivalent to sildenafil-like action or assign results from Pycnogenol-arginine combinations to citrulline alone. Direct standalone evidence is not comparable to evidence for prescription PDE5 inhibitors.
Useful facts when choosing a product
- Korean online and cross-border markets sell L-citrulline powders and 750 mg capsules, including products providing 1,500 mg per two capsules.
- The direct mild-erectile-dysfunction study used standalone L-citrulline at 1.5 g/day for one month.
- Citrulline malate, arginine-Pycnogenol-roburin combinations, and pre-workout blends differ from standalone L-citrulline.
- No adverse events were reported in the short 24-person study, but potential blood-pressure effects should be reviewed with a clinician when used with antihypertensives, nitrates, PDE5 inhibitors, or cardiovascular disease.
What the research actually shows
The 2011 study by Cormio and colleagues gave 24 men with an erection hardness score of 3 one month of placebo followed by one month of L-citrulline at 1.5 g/day. Improvement to score 4 occurred in 2 men during placebo and 12 men during citrulline, and intercourse frequency also increased. The study was single-blind and sequential, and the authors noted lower efficacy than PDE5 inhibitors. The 2024 network meta-analysis by Barbonetti and colleagues synthesized 15 randomized trials involving 1,000 men, but statistically significant signals centered on L-arginine or carnitine-PDE5 inhibitor combinations, with no significant efficacy for other regimens.
Why this is classified as C (40)
A direct human signal prevents a deferred or D rating, but evidence centers on one 24-person nonrandomized sequential single-blind pilot, and combination results cannot be assigned to citrulline alone. Calibration with the arginine precedent supports C with 46 points.
Counterpoint. A randomized double-blind parallel trial powered for IIEF, erection hardness, and response rates is required for an upgrade.
Rejudgment record. New verdict — Counted only the 24-person nonrandomized sequential single-blind direct study and excluded attribution from combinations containing Pycnogenol, arginine, and other ingredients
Cross-check — Codex and Claude
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Cormio L et al. 2011 | Single-blind placebo-controlled nonrandomized sequential pilot | 24 | Not clearly reported | Erection hardness score, intercourse frequency, and satisfaction | Improvement from EHS 3 to 4 occurred in 8.3% during placebo and 50% during L-citrulline at 1.5 g/day. | Key |
| Barbonetti A et al. 2024 | Systematic review and network meta-analysis | 1,000 | Academic review; funding varied across included trials | IIEF-5 or IIEF-6 erectile-function scores | Significant efficacy centered on selected arginine and carnitine-PDE5 inhibitor regimens; other regimens were not significant. | Supportive |
Receipt — 2 References
All 2 cited sources were verified for existence at the original page (as of 2026-07-18).
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-07-18 · Corrections: none
Cite this verdict
[Chamgap] L-citrulline x erection hardness and sexual function in mild erectile dysfunction — Evidence Grade C·40. 2 cited sources checked. Source: https://chamgap.com/en/verdicts/mens/l-citrulline-mild-erectile-dysfunction/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
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