The Claim

A single 500 mL dose of L-citrulline-enriched watermelon juice containing 3.45 g L-citrulline has no effect on half-marathon race time in amateur male runners, as no significant difference in mean race time was observed between the supplemented group and the placebo group (99.9 minutes for both).

Source: Biochemical, physiological, and performance response of a functional watermelon juice enriched in L-citrulline during a half-marathon race

What the research says

Supports is higher

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

Supports
61score
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.

Quantitative
1 study reviewed
In plain English

Drinking 500 mL of watermelon juice with 3.45 grams of L-citrulline before a half-marathon does not change the race time of amateur male runners compared to drinking a placebo beverage.

See the scientific wording

A single 500 mL dose of L-citrulline-enriched watermelon juice (3.45 g L-citrulline) does not improve half-marathon race time in amateur male runners, with no significant difference observed between supplemented and placebo groups (mean time: 99.9 minutes for both).

Why this might work

L-citrulline is converted into arginine, which triggers the production of nitric oxide, causing blood vessels to widen and deliver more oxygen to muscles. At the same time, L-citrulline helps remove ammonia, a waste product from intense exercise, which reduces the body's reliance on energy pathways that produce lactic acid. This allows muscles to work longer without accumulating fatigue-causing acids, preserving strength and reducing soreness after exercise.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Biochemical, physiological, and performance response of a functional watermelon juice enriched in L-citrulline during a half-marathon race

    The study found that drinking this watermelon juice before a half-marathon didn’t make runners any faster than drinking a fake juice — they both finished in the same time. So yes, it doesn’t help you run quicker.

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

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