The Claim

Supplementation with 300 mL/day of watermelon juice concentrate providing 3.4 g of L-citrulline daily for 16 days increases baseline plasma nitrite concentrations by approximately 97% and enhances skeletal muscle oxygenation during moderate-intensity exercise in healthy recreationally-active adult males, but does not improve time-to-exhaustion during severe-intensity exercise.

Source: Two weeks of watermelon juice supplementation improves nitric oxide bioavailability but not endurance exercise performance in humans.

What the research says

Supports is higher

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

Supports
46score
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.

Cause and effect
1 study reviewed
In plain English

Daily consumption of 300 mL of watermelon juice concentrate containing 3.4 grams of L-citrulline for 16 days raises plasma nitrite levels by about 97% and improves oxygen delivery to skeletal muscles during moderate exercise in healthy adult males, but does not extend the time until exhaustion during high-intensity exercise.

See the scientific wording

Supplementation with 300 mL/day of watermelon juice concentrate providing 3.4 g of L-citrulline daily for 16 days increases baseline plasma nitrite concentrations by approximately 97% and enhances skeletal muscle oxygenation during moderate-intensity exercise in healthy recreationally-active adult males, but does not improve time-to-exhaustion during severe-intensity exercise.

Why this might work

When L-citrulline is consumed, it is absorbed into the blood and carried to the kidneys, where it is turned into L-arginine. L-arginine then fuels the production of nitric oxide in blood vessel walls. Nitric oxide spreads to nearby muscle blood vessels and causes them to widen, allowing more blood and oxygen to reach the muscles during moderate exercise.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Two weeks of watermelon juice supplementation improves nitric oxide bioavailability but not endurance exercise performance in humans.

    Drinking this special watermelon juice for two weeks raised a chemical in the blood that helps deliver oxygen to muscles during moderate exercise, but didn’t help people exercise harder or longer during intense workouts.

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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