Beta-alanine supplementation has been shown to increase skeletal muscle carnosine concentration resulting in the delay of neuromuscular fatigue and an increased aerobic and anaerobic capacity. The current study investigated the effects of beta-alanine supplementation on aerobic and anaerobic capacity in trained cyclists. Fourteen highly-competitive (sprint, endurance, road and track) cyclists underwent an 8 week 6.4g/day protocol (beta-alanine and maltodextrin). Pre and post supplementation testing included a VO₂max test (familiarization and characterization), maximum aerobic power test (aerobic capacity), and 30s wingate anaerobic test (anaerobic capacity). Aerobic capacity parameter measures included aerobic and anaerobic thresholds, and maximum aerobic power, while anaerobic capacity parameters included fatigue index, average power, peak power, watts per kilogram, and final lactate concentration. There was a lack of change in aerobic and anaerobic capacity parameters post supplementation for both groups. Assuming an increase in skeletal muscle carnosine concentration, results suggest 8 weeks 6.4g/day beta-alanine does not increase aerobic and anaerobic capacity in trained cyclists. This lack of change has 3 potential explanations; carnosines’ physicochemical H⁺ buffering ability was not substantially elevated to prevent muscular fatigue via acidosis, pH decrease is only one limiting factor in aerobic and anaerobic capacity, or other factors (neuromuscular junction failure, contractile failure, substrate depletion, metabolite accumulation, oxidative stress) influence muscular fatigue.