Strongest evidence: The only outcome with moderate-strength evidence is Increased Carnosine Level. All 3 studies reported beneficial effects, with mixed effect sizes (small to large). The most studied dose was 3.2 g/day, and effects were seen in patients with COPD and combat athletes over a median of 84 days. No other outcomes reached this level of evidence.
Mixed or weaker evidence: 8 outcomes had low or very low evidence. Improved Physical Performance showed mixed results (2 beneficial, 2 neutral; small effects; low evidence). Improved Time to Exhaustion also had mixed findings (2 beneficial, 1 neutral). The remaining outcomes – Reduced Heart Rate, Improved Peak Power, Reduced Lactate Levels, Reduced Rating of Perceived Exertion, Reduced Body Fat Mass, and Reduced Body Mass – all showed predominantly neutral results (small effect sizes, no statistically significant benefits). For example, all 5 studies on heart rate were neutral, and all 3 on body mass were neutral.
Effective dose patterns: A dose of 6.4 g/day appears across multiple outcomes (physical performance, reduced RPE, reduced body mass), though evidence is limited. For carnosine levels, the only effective dose reported was 3.2 g/day. No consistent dose emerged for other outcomes due to low study numbers and varied protocols.
Population insights: The majority of studies used athletes (combat sports, cyclists, military personnel) or active individuals. One study on carnosine levels included COPD patients, suggesting potential clinical relevance. No other specific populations (e.g., elderly, sedentary) were well represented.
Notable caveats: The evidence base is small across all outcomes (3–5 studies each). Many studies did not reach statistical significance, effect sizes varied widely, and publication bias is a concern (null results less likely to be published). Several studies co-supplemented beta-alanine with creatine, making it difficult to isolate effects. Study durations were often short (e.g., 7–28 days), which may be insufficient for some outcomes.