Taking L-citrulline or L-arginine supplements doesn’t seem to help swimmers go faster in short races like 100m or 200m—maybe because these races are so quick that your body doesn’t use the kind of blood flow changes those supplements try to create.
Claim Language
Language Strength
probability
Uses probability language (may, likely, can)
The claim uses 'may be due to', which expresses possibility rather than certainty, indicating a probabilistic rather than definitive or associative relationship.
Context Details
Domain
exercise_science
Population
human
Subject
L-citrulline or L-arginine supplementation
Action
may be due to
Target
the lack of performance improvement in 100-m and 200-m swimming
Intervention Details
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Evidence from Studies
Supporting (1)
Eight Days of L-Citrulline or L-Arginine Supplementation Did Not Improve 200-m and 100-m Swimming Time Trials
The study gave swimmers L-citrulline or L-arginine pills and found they didn’t swim any faster in short races — which supports the idea that these supplements don’t help for quick, all-out swims because those races don’t use the body systems the supplements target.