Why swimming supplements didn't make swimmers faster
Eight Days of L-Citrulline or L-Arginine Supplementation Did Not Improve 200-m and 100-m Swimming Time Trials
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
L-citrulline increased plasma arginine more than L-arginine—but still didn't improve performance or NOx levels.
This contradicts the entire marketing premise: if L-citrulline is better absorbed and converts to arginine, it should outperform L-arginine. But it didn't—even on its own metric.
Practical Takeaways
Don't waste money on L-citrulline or L-arginine for short-distance swimming, sprinting, or high-intensity events under 5 minutes.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
L-citrulline increased plasma arginine more than L-arginine—but still didn't improve performance or NOx levels.
This contradicts the entire marketing premise: if L-citrulline is better absorbed and converts to arginine, it should outperform L-arginine. But it didn't—even on its own metric.
Practical Takeaways
Don't waste money on L-citrulline or L-arginine for short-distance swimming, sprinting, or high-intensity events under 5 minutes.
Publication
Journal
International Journal of Environmental Research and Public Health
Year
2022
Authors
O. Esen, M. Eser, Mekki Abdioğlu, D. Benešová, T. Gabryś, Raci Karayiğit
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Claims (6)
Taking L-citrulline by mouth raises your blood levels of L-arginine better than taking L-arginine directly, because your body processes L-citrulline more efficiently and doesn’t break it down too early in the liver.
Taking L-citrulline or L-arginine supplements for eight days doesn’t make swimmers any faster in 100m or 200m races, even if they’re trained athletes.
Taking L-citrulline or L-arginine supplements for 8 days doesn’t help trained swimmers and triathletes feel less burned out or reduce the buildup of lactic acid in their blood during short, intense freestyle races.
Taking L-citrulline or L-arginine supplements doesn't seem to help competitive swimmers swim faster in 100m or 200m races, even though scientists thought these supplements might help by improving blood flow or reducing muscle burn.
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.