Beta-Alanine for Muscle Gain
Beta-alanine does not increase muscle mass or lean body mass. Its proven role is buffering muscle acid to support short, high-intensity efforts, not driving muscle growth.
Why this grade7-layer evidence engine
The grade reflects direct counter-evidence rather than mere absence of data. The definitive source, a 2022 GRADE-assessed meta-analysis of 20 RCTs (n=492, PMID 35813845), found no effect on fat-free mass (WMD 0.05 kg, 95% CI -0.71 to 0.82, p=0.889) and concluded beta-alanine is unlikely to improve body composition regardless of dose or exercise type.
Individual trials agree. A 10-week resistance-training RCT (PMID 18175046) saw no change in body mass, body fat, or strength even though muscle carnosine rose markedly. A recovery-focused RCT (PMID 30627787) found no body-composition benefit. The one lean-mass signal (PMID 19210788) appeared only alongside high-intensity interval training and is best explained by greater training volume, not any direct anabolic action.
Authorities align with the trials. Beta-alanine has no muscle-building mechanism; it forms carnosine, which buffers acid. The EU EFSA rejected all related health claims for insufficient cause-and-effect evidence, the US FDA lists it only as a nutrient supplement/flavoring with no approved efficacy claim, and Mayo Clinic and sports-nutrition bodies describe its value for high-intensity endurance, not hypertrophy.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.302
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高階證據未達主導 (0 positive vs 1 negative)，由 raw_score 決定
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status