The Claim

Female participants receiving 10-day L-citrulline supplementation at 100 mg/kg/day showed a trend toward increased time to exhaustion compared to baseline or control, with mean values of 24.4 ± 6.2 minutes versus 21.9 ± 4.8 minutes (p=0.06), suggesting a potential sex-specific effect.

Source: Ergogenic effects of a 10-day L-citrulline supplementation on time to exhaustion and cardiorespiratory and metabolic responses in healthy individuals: a double-blind, randomised, placebo-controlled crossover trial

What the research says

Supports is higher

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

Supports
67score
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.

Description
1 study reviewed
In plain English

In women, taking L-citrulline for 10 days at 100 mg per kilogram of body weight was associated with a slight increase in how long they could exercise before fatigue, compared to their previous performance, though the difference was not statistically significant.

See the scientific wording

A trend toward improved time to exhaustion was observed in female participants receiving 10-day L-citrulline supplementation at 100 mg/kg/day (24.4 ± 6.2 vs. 21.9 ± 4.8 min, p=0.06), suggesting a potential sex-specific effect that warrants dedicated investigation.

Why this might work

L-citrulline is turned into arginine in the kidneys, which gives more raw material to blood vessel cells to make nitric oxide. Nitric oxide tells blood vessels to widen, allowing more blood and oxygen to reach working muscles. This helps muscles keep working longer before they get tired.

Suggested mechanismbased on 1 study

What the research says

1 study
  1. Study: Ergogenic effects of a 10-day L-citrulline supplementation on time to exhaustion and cardiorespiratory and metabolic responses in healthy individuals: a double-blind, randomised, placebo-controlled crossover trial

    In this study, women who took L-citrulline were able to exercise a little longer before getting tired, though the result wasn’t strong enough to be 100% certain it wasn’t just luck. The researchers think this might be something special to women and say it’s worth studying more.

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.

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