MSM / Methylsulfonylmethane for Osteoarthritis
The evidence that MSM (methylsulfonylmethane) meaningfully relieves osteoarthritis is weak and inconsistent: a handful of small, short trials hint at modest symptom improvement, but the strongest pooled analysis found no clinically meaningful benefit. It may offer a slight, uncertain edge at best and should not be relied on as a treatment.
Why this grade7-layer evidence engine
The human data are thin and conflicting. Small double-blind trials report some improvement in WOMAC pain or function (PMID 16309928, n=50; PMID 21708034, n=49), but the authors themselves called the changes small and of uncertain clinical significance, and pain effects often missed statistical significance. Trials were all short (about 12 weeks) and low to moderate quality.
Critically, the highest-tier evidence is negative: a meta-analysis (PMID 19474240) found only a non-significant 6.34 mm reduction in pain on a visual-analogue scale and concluded MSM is not clinically effective for knee osteoarthritis. The largest positive trial (PMID 28790224, n=147) combined MSM with glucosamine and chondroitin, so it cannot isolate any MSM-specific effect, and the 2023 trial (PMID 37447322) enrolled people with only mild knee pain rather than diagnosed osteoarthritis and was industry-funded.
Authorities echo this caution, which anchors the weak grade. Mayo Clinic notes 'modest' improvements from studies too limited in scope and duration to draw firm conclusions, Harvard Health takes an against stance, and EU regulators rejected MSM joint-health claims. The US FDA's involvement is limited to recognizing MSM as safe (GRAS), not effective. Industry-linked funding further tempers confidence.
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 = 0.545
- 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 + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status