L-Citrulline and Blood Pressure: Evidence, Usage, and Safety (vs. L-Arginine)

Reading time: 9–12 minutes • Educational only.

What the research suggests

• L-citrulline meta-analysis (8 trials): pooled changes SBP −4.10 mmHg (95% CI −7.94 to −0.26); DBP −2.08 mmHg overall, with significant DBP reduction at ≥6 g/day.
• L-arginine (22 RCTs): average SBP −6.4 mmHg and DBP −2.6 mmHg in dose-response analysis.
• Why citrulline is often preferred: it raises plasma arginine more reliably than oral arginine (better bioavailability), supporting NO production.

Takeaway: effects are small on average and should be viewed as adjunctive.

How people typically use it (study-aligned)

• Dose & duration: 3–6 g/day L-citrulline for 2–8+ weeks. Split doses if GI upset.
• When to take: with or without food; keep timing consistent.
• How to track: capture a 7-day average before and after 2–4 weeks: How to Measure & Track.

Safety & interactions

• Additive BP-lowering with antihypertensives is possible—coordinate with your clinician.
• Caution with nitrates or PDE-5 inhibitors: NO-pathway supplements (arginine/citrulline) may potentiate hypotension; PDE-5 inhibitors and nitrates should not be combined without medical supervision.
• Typical side effects are uncommon (GI upset, headache); discontinue if adverse effects occur.

Lifestyle tie-ins

• Diet & Lifestyle
• Supplement Comparison Hub

Educational Disclaimer: This article is for educational purposes only and is not medical advice.

References

1. Barkhidarian B, et al. L-citrulline and BP (meta-analysis). PMC.
2. Shiraseb F, et al. L-arginine and BP (dose-response meta-analysis). ScienceDirect. See summary: Mayo Clinic.
3. Rashid J, et al. Citrulline as an arginine supplement (PK/PD). PMC.
4. Drugs.com Professional — Arginine/Citrulline & vasodilators. Drugs.com.
5. ACC / StatPearls — PDE-5 inhibitors + nitrates. ACC ; StatPearls.