The Claim

The co-administration of 1 g L-citrulline and 1 g L-arginine results in a higher peak plasma L-arginine concentration at 1 hour post-ingestion compared to the administration of 2 g of either L-citrulline or L-arginine alone in healthy males.

Source: The effects on plasma L-arginine levels of combined oral L-citrulline and L-arginine supplementation in healthy males

What the research says

Supports is higher

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

Supports
69score
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

When healthy men take 1 gram of L-citrulline and 1 gram of L-arginine together, their blood L-arginine levels reach a higher peak after one hour than when they take 2 grams of either amino acid by itself.

See the scientific wording

The combination of 1 g L-citrulline and 1 g L-arginine produces a higher peak plasma L-arginine concentration at 1 hour post-ingestion than either amino acid administered alone at 2 g, indicating a synergistic short-term effect on bioavailability in healthy males.

Why this might work

When L-citrulline and L-arginine are taken together, L-citrulline blocks an enzyme that breaks down L-arginine, allowing more L-arginine to enter the bloodstream without being destroyed in the gut or liver.

Supported mechanismbased on 1 study

What the research says

1 study
  1. Study: The effects on plasma L-arginine levels of combined oral L-citrulline and L-arginine supplementation in healthy males

    When you take 1 gram of citrulline and 1 gram of arginine together, your body ends up with more arginine in your blood after one hour than if you took 2 grams of just one of them alone — they work better as a team.

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.