The Claim

Acute ingestion of 6 g or 12 g citrulline malate in healthy young males does not significantly improve flow-mediated dilation of the brachial artery within 120 minutes, despite increasing serum concentrations of citrulline, arginine, and ornithine, indicating that enhanced substrate availability alone is insufficient to improve endothelial-dependent vasodilation at rest in this population.

Source: Acute effect of citrulline malate on flow-mediated dilation and serum pharmacodynamics in healthy young males

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
68score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

Taking 6 or 12 grams of citrulline malate increases certain amino acids in the blood but does not improve blood vessel dilation in healthy young men within two hours.

See the scientific wording

Acute ingestion of 6 g or 12 g citrulline malate in healthy young males does not significantly improve flow-mediated dilation of the brachial artery within 120 minutes, despite increasing serum concentrations of citrulline, arginine, and ornithine, suggesting that enhanced substrate availability alone is insufficient to improve endothelial-dependent vasodilation at rest in this population.

Why this might work

When citrulline is taken, the body turns it into arginine, which is used to make nitric oxide, a molecule that tells blood vessels to open up. But in healthy young men at rest, the blood vessels are already using all the arginine they can, so more arginine does not make them open any further.

Supported mechanismbased on 1 study

What the research says

1 study

  1. Study: Acute effect of citrulline malate on flow-mediated dilation and serum pharmacodynamics in healthy young males

    Taking 6 or 12 grams of citrulline malate raised certain blood chemicals that should help blood vessels relax, but the vessels didn’t actually get any wider. So, just having more of these chemicals doesn’t automatically improve blood flow in healthy young men.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.