From the databaseWhat the row says.
Every entry follows the same shape: what is happening, the mechanism, and the recommendation.
Scope
Supplement × Supplement
Last verified
June 4, 2026
CautionEmerging evidence
What is happening. L-citrulline can increase nitric oxide-mediated vasodilation and may add to VIP-related flushing or low blood pressure.
Mechanism. Additive vasodilatory physiology.
Recommendation. Avoid combining if prone to hypotension, syncope, or using antihypertensive drugs.
Stack Score
How it moves the number.
Effect on the composite score
If both L-Citrulline and VIP (Vasoactive Intestinal Peptide) are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are at /methodology/stack-score.
SourcesSources, by evidence tier.
Every claim on this page is cited. PMIDs link straight to PubMed.
Reference material
1- 1Petkov V et al. VIP in primary pulmonary hypertension. J Clin Invest. 2003.Needs sourceNo link