BCAA / Branched-Chain Amino Acids for Exercise Recovery
BCAA supplements may modestly reduce muscle soreness and some damage markers after hard exercise, but the effect is inconsistent and likely small once you already eat enough protein. They do not meaningfully speed up actual recovery of muscle performance, so the evidence is rated weak.
Why this grade7-layer evidence engine
Four meta-analyses and overviews of systematic reviews drive the weak (C) grade, and they disagree. A 2024 meta-analysis (PMID 38625669) found large reductions in delayed-onset soreness (Hedges g around -1.75 at 48h) and lower creatine kinase, and a 2024 overview of reviews (PMID 38241335) reported medium effects on CK and small-to-large effects on soreness. But the older 2017 meta-analysis (PMID 28870476) found CK reduced yet soreness and LDH unchanged, and a 2021 meta-analysis (PMID 34669012) saw benefit in only 7 of 10 trials with high between-study variability.
Two limitations cap the grade. Most trials never controlled participants' baseline protein intake, so the apparent benefit may simply reflect topping up an inadequate diet rather than a special BCAA effect. And across reviews there was consistently no improvement in LDH, myoglobin, or actual muscle-performance recovery (PMID 38241335) — the measured wins are mostly surrogate markers. The supporting single RCT (PMID 33539692) had just 12 people.
Authorities are split, which matches a weak verdict. The US FDA treats BCAAs only as a GRAS nutrient supplement and approves no efficacy claim, while EU EFSA formally rejected all BCAA recovery and fatigue claims in 2010 for lack of established cause and effect. NIH ODS and a relevant specialty society are cautious, Cleveland Clinic is mildly supportive, and the WHO and UK NHS take no position on supplementation. Bottom line: possible small help with soreness, but no reliable recovery boost, especially if protein intake is already adequate.
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 = 0.512
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (3 篇 > 1 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status