HMB / Beta-Hydroxy Beta-Methylbutyrate for Exercise Recovery
HMB shows only weak, inconsistent evidence for speeding exercise recovery: it may modestly lower blood markers of muscle damage, but most other recovery outcomes show no benefit, and effects are unreliable in trained athletes. It is not an established recovery aid.
Why this grade7-layer evidence engine
A 2024 umbrella review (PMID 37460208) found HMB significantly reduced post-exercise creatine kinase and LDH with moderate certainty, and two earlier systematic reviews (PMID 36775650, PMID 29037326) reported similar muscle-damage marker signals plus a possible work-capacity benefit (PMID 29420925, n=23). But these reductions are surrogate blood markers; soreness, inflammation, fatigue, and range-of-motion typically show no benefit, so the clinical payoff is small.
The evidence is also inconsistent and thin. The supporting RCTs are tiny (most n<30), and a 10-week double-blind trial in trained subjects (PMID 31952174, n=28) found no effect of HMB alone on CK, LDH, or AST. Benefits cluster in untrained or older people and in the free-acid form, while the combination of HMB plus creatine appears ineffective for recovery.
Authorities are unconvinced. The EU's EFSA rejected all HMB recovery and tissue-repair health claims for lack of an established cause-and-effect relationship, and the US FDA has set no approved health claim. NIH and sports-nutrition society positions are cautious, with the favorable society stance carrying notable industry conflicts of interest. Together this supports a weak-evidence grade rather than endorsement.
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 = 0.468
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 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