Acute Effects of Creatine and L-Arginine Co-Supplementation on Anaerobic and Cognitive Performance in Recreationally Active Males

Creatine monohydrate and L-arginine are widely used ergogenic supplements that may influence performance through different physiological mechanisms. Creatine contributes to rapid adenosine triphosphate resynthesis through phosphocreatine availability, whereas L-arginine serves as a precursor for nitric oxide synthesis and may enhance blood flow and substrate delivery during exercise. Their combined administration may therefore produce complementary effects on physical and cognitive performance.

This study uses a randomized, double-blind, four-treatment crossover design in recreationally active adult males. Each participant completes four conditions: placebo, creatine monohydrate, L-arginine, and combined creatine plus L-arginine. Sessions are separated by at least 72 hours, and all testing is conducted at the same time of day. Supplementation is administered 60 minutes before performance testing. Creatine is provided as a single acute dose of 0.3 g/kg, L-arginine as 6 g, and the placebo as a matched control beverage.

Outcome assessments include the Running-Based Anaerobic Sprint Test for repeated-sprint power, the countermovement jump test for explosive lower-body performance, and the Stroop Color-Word Test for cognitive reaction time and accuracy. The primary objective is to examine whether acute co-supplementation with creatine and L-arginine improves anaerobic and cognitive outcomes more than placebo or either supplement alone.

Inclusion criteria

• Male recreational athletes aged 18 years or older
• At least 2 years of regular participation in organized sport
• Apparently healthy and able to complete high-intensity exercise testing

Exclusion criteria

• Known orthopedic, neurological, cardiovascular, pulmonary, or metabolic disorders
• Use of anabolic steroids or performance-enhancing drugs within the previous 3 months
• Use of psychoactive or stimulant substances during the study