The Claim

In healthy, moderately active young adults, a 10-day supplementation with L-citrulline at a dosage of 100 mg/kg/day has no significant effect on cardiac output, oxygen uptake, blood pressure, lactate levels, or glucose responses during high-intensity cycling to exhaustion.

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

Taking L-citrulline supplements for 10 days at 100 mg per kilogram of body weight does not change how the heart pumps blood, how much oxygen the body uses, blood pressure, lactate levels, or blood glucose during intense cycling to exhaustion in healthy young adults.

See the scientific wording

In healthy, moderately active young adults, a 10-day L-citrulline supplementation at 100 mg/kg/day does not significantly alter cardiac output, oxygen uptake, blood pressure, lactate, or glucose responses during high-intensity cycling to exhaustion.

Why this might work

L-citrulline is absorbed from the gut and converted into arginine in the kidneys. Arginine is used by blood vessel cells to make nitric oxide, which relaxes blood vessels and increases blood flow. This should improve oxygen delivery to muscles during exercise, but in healthy young adults, this pathway does not change heart output, oxygen use, blood pressure, lactate, or glucose levels during intense cycling.

Hypothetical 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

    This study gave people L-citrulline pills for 10 days and had them bike really hard. Their heart, lungs, blood pressure, and muscle chemicals didn't change compared to when they took a sugar pill — so the supplement didn't make a difference.

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.