MSM
Evidence Fact Sheet
Methylsulfonylmethane
MSM (methylsulfonylmethane) is an organic-sulfur dietary supplement studied for joint comfort and exercise recovery via sulfur-donor and NF-κB / antioxidant pathways. Human RCTs at ~3 g/day show modest, mixed knee-osteoarthritis benefits and antioxidant effects after exercise, with honest negatives. US GRAS (OptiMSM); no EFSA-authorized claim.
Also known as: Methylsulfonylmethane · Dimethyl sulfone · DMSO2 · OptiMSM · MSM
Overview
MSM (methylsulfonylmethane, also DMSO2) is a naturally occurring organic sulfur compound — the oxidized metabolite of DMSO — marketed as a dietary supplement for joint support and exercise recovery. Mechanistically it is studied as a bioavailable sulfur donor for connective-tissue substrate synthesis, an inhibitor of NF-κB inflammatory signaling, and a glutathione-supportive antioxidant that lowers exercise-induced ROS and pro-inflammatory cytokine signaling. Typical research doses are about 3 g/day for 12 weeks in joint-osteoarthritis trials and 4–8 weeks in exercise-recovery trials, with common commercial doses of 1.5–3 g/day and short-term study use up to 6 g/day. In the US it is a lawful dietary-supplement ingredient under DSHEA and the OptiMSM brand holds an independent GRAS determination; the EU permits it as a food-supplement ingredient but has no authorized health claim under Reg 432/2012, and no specific functional claim is identified in Brazil (ANVISA) or on China's health-food positive list. This is an evidence-reporting overview, not medical guidance.
Mechanism of Action
Organic sulfur (bioavailable sulfur) donor for connective-tissue substrate synthesis · NF-κB signaling inhibition (research-context anti-inflammatory pathway) · Free-radical / ROS scavenging and glutathione-supportive antioxidant activity · Reduction of exercise-induced pro-inflammatory cytokine signaling (IL-6, CRP) in trials
Body systems: Musculoskeletal · Skin & Connective Tissue · Immune System
Evidence-Based Benefits
Each benefit below is anchored to a specific PubMed-indexed study. Effect sizes, sample sizes, and p-values are reported as published; no values are inferred. Honest negatives and null results are kept alongside the positive findings, and disease-research populations are described as such — MSM is not characterized as a treatment for any disease.
Knee Osteoarthritis — Pooled Systematic Review
Meta-analysis supported- 6 studiesDMSO + MSM trials
- 52 on active treatmentMSM patients (of 168)
- both MSM trialssignificant pain improvement
A systematic review of the related sulfur supplements DMSO and MSM in knee osteoarthritis pooled six trials. Both MSM trials reported significant pain improvement versus comparator, but the authors stressed the evidence was positive yet not definitive and drew no firm conclusion for either supplement. This is a qualitative review-level synthesis rather than a single pooled numeric effect for MSM.
Reported effect: Six studies, 168 patients for MSM (N=52 on active treatment); both MSM trials reported significant pain improvement; conclusion: positive but not definitive evidence that MSM is superior to placebo in mild-to-moderate knee OA.
“six studies...evaluating a total of 681 patients with OA of the knee for DMSO (N=297 on active treatment); 168 patients for MSM (N=52 on active treatment). Two of the four DMSO trials, and both MSM trials reported significant improvement in pain outcomes in the treatment group compared to comparator treatments. ... positive but not definitive evidence that MSM is superior to placebo in the treatment of mild to moderate OA of the knee.”
Source: PMID 18417375 · Brien 2008 · Osteoarthritis Cartilage
Knee Osteoarthritis Pain & Function — Pilot RCT
RCT supported- 3 g twice dailyMSM vs placebo
- P<0.05WOMAC pain & function
In a 12-week pilot RCT, MSM dosed 3 g twice daily significantly reduced WOMAC pain and physical-function impairment versus placebo and improved activities of daily living on the SF-36. Notably, no significant changes were seen in WOMAC stiffness or aggregated total symptom scores — a partial, not blanket, benefit.
Reported effect: MSM 3 g twice daily for 12 weeks produced significant decreases in WOMAC pain and physical function impairment (P<0.05); no notable changes in WOMAC stiffness or total symptom scores.
“Compared to placebo, MSM produced significant decreases in WOMAC pain and physical function impairment (P<0.05). MSM also produced improvement in performing activities of daily living when compared to placebo on the SF-36 evaluation (P<0.05). No notable changes were found in WOMAC stiffness and aggregated total symptoms scores.”
Source: PMID 16309928 · Kim 2006 · Osteoarthritis Cartilage
Knee Osteoarthritis — Function vs Pain (Mixed RCT)
RCT supported- 14.6 mmWOMAC physical function · p=0.04
- 15.0 mmWOMAC total score · p=0.03
- p=0.08WOMAC pain — NOT significant
A 12-week RCT (n=49) of MSM 1.125 g three times daily found significant between-group improvement in WOMAC physical function (14.6 mm, p=0.04) and total score (15.0 mm, p=0.03). However, WOMAC pain (12.4 mm, p=0.08) and stiffness (p=0.08) did not reach significance — an honest illustration that function gains outpaced pain relief.
Reported effect: WOMAC physical function 14.6 mm (CI 4.3, 25.0; p=0.04) and total score 15.0 mm (CI 5.1, 24.9; p=0.03) significant; WOMAC pain 12.4 mm (p=0.08) and stiffness (p=0.08) not significant.
“significant differences between treatment groups over time in WOMAC physical function (14.6 mm [CI: 4.3, 25.0]; p = 0.04) ... in WOMAC total score (15.0 mm [CI: 5.1, 24.9]; p = 0.03) ... Treatment groups did not differ significantly in WOMAC pain (12.4 mm [CI: 0.0, 24.8]; p = 0.08) ... or WOMAC stiffness (27.2 mm [CI: 8.2, 46.2]; p = 0.08)”
Source: PMID 21708034 · Debbi 2011 · BMC Complement Altern Med
Knee-Pain Prevention in Healthy Trainees — Honest Negative
Null / no benefit RCT supported- 3 g/day · 8 weeksMSM vs placebo
- no significantKOOS & POMS at 30 & 60 d
In a randomized placebo-controlled trial in military initial-entry trainees, 3 g/day MSM did not significantly improve any of the 5 KOOS knee subscales or 6 POMS mood subscales at 30 or 60 days. MSM was used safely but showed no preventive benefit — a clear honest negative in a healthy, non-osteoarthritis population.
Reported effect: 3 g/day MSM showed no significant improvement in 5 KOOS subscales or 6 POMS subscales at 30 or 60 days versus placebo.
“Three grams of MSM administered daily did not provide significant improvements in the 5 KOOS subscales or the 6 POMS subscales at 30 days or 60 days. ... Although 3 grams of MSM daily can be used safely, there does not appear to be a significant improvement in KOOS or POMS.”
Source: PMID 29214616 · Tennent 2017 · US Army Med Dep J
Exercise Recovery / Oxidative Stress — Half-Marathon RCT
Null / no benefit RCT supported- Δ > 10 mmmuscle/joint pain (within-group only)
In a double-blind RCT, runners took 3 g/day MSM around a half-marathon. The primary time-by-treatment comparison did not reach statistical significance for any outcome — oxidative stress (8-OHdG), muscle damage (CK, LDH) and pain all rose with the race regardless of treatment. The MSM group did show a within-group clinically meaningful (Δ > 10 mm) drop in muscle and joint pain, but this was not a significant between-group effect.
Reported effect: Time-by-treatment did not reach statistical significance for any outcome; MSM group saw clinically significant (Δ > 10 mm) reductions in muscle and joint pain (within-group, not between-group significant).
“Time-by-treatment results did not reach statistical significance for any outcome measure, however, the MSM group saw clinically significant (Δ > 10 mm) reductions in both muscle and joint pain.”
Source: PMID 28736511 · Withee 2017 · J Int Soc Sports Nutr
Exercise Muscle Damage & Antioxidant Capacity — RCT
RCT supported- P=0.041lower CK vs placebo at 24 h
- P=0.014 / 0.033higher TAC at 2 h / 24 h
A 10-day double-blind trial in 18 active young men (50 mg/kg MSM) found that after exhaustive exercise, the placebo group's creatine kinase and bilirubin rose significantly more than the MSM group, and total antioxidant capacity was significantly higher in the MSM group at 2 h and 24 h. This supports MSM's antioxidant/recovery mechanism in a small sample.
Reported effect: CK and bilirubin rose more in placebo vs MSM at 24 h (P=0.041 and P=0.002); TAC higher in MSM group at 2 h and 24 h post-exercise (P=0.014 and P=0.033).
“CK and bilirubin significantly increased in P group 24 h after exercise compared to M group (P=0.041 and P=0.002, respectively). ... TAC showed significant increase in M group 2 and 24 h after exercise compared to P group (P=0.014 and P=0.033, respectively).”
Source: PMID 22525653 · Barmaki 2012 · J Sports Med Phys Fitness
Knee Quality of Life in Mild Knee Pain — RCT
RCT supported- p=0.046JKOM total score vs placebo
- p=0.032JKOM health condition
In a 12-week RCT, 88 participants with mild knee pain took MSM (10 tablets of 200 mg/day) or placebo. The primary JKOM total score differed significantly between groups (p=0.046) and the JKOM health-condition subscore improved (p=0.032). The abstract reports significance via p-values only, without further numeric effect sizes.
Reported effect: JKOM total score at 12 weeks differed significantly between MSM and placebo (p=0.046); JKOM health condition also improved (p=0.032).
“The total scores at 12 weeks in the MSM and placebo groups as the primary outcome were significantly different (p = 0.046). The health condition of JKOM also improved after MSM consumption (p = 0.032).”
Source: PMID 37447322 · Toguchi 2023 · Nutrients
Dosage (research context · not a recommendation)
3 g/day in RCTs (joint OA · 12 weeks; exercise recovery · 4-8 weeks); common commercial dose 1.5-3 g/day; short-term studies to 6 g/day without serious adverse events (educational reference, not a recommendation)
Regulatory Status · 4 Markets
- US · FDA
- Lawful dietary supplement ingredient under DSHEA; OptiMSM (Bergstrom Nutrition) holds an independent GRAS determination; Structure/Function claims permitted with mandatory FDA disclaimer; no standardized upper limit
- EU · EFSA
- Permitted as a food supplement ingredient (member-state level, some variation); NO EFSA-authorized health claim under Reg 432/2012
- CN · China
- No confirmed China regulatory status identified: MSM is not on the SAMR health-food positive list, not a novel/medicinal-food ingredient, sold domestically only via cross-border e-commerce.
- BR · ANVISA
- Permitted as a dietary/food supplement ingredient under the ANVISA framework; no specific authorized functional claim (alegação funcional) identified
Safety
Well tolerated at 1.5-6 g/day in clinical trials; common adverse events (mild GI discomfort, headache) not significantly different from placebo. OptiMSM holds GRAS status. Long-term (>12 months) high-dose safety data are limited. Caution advised with anticoagulants (theoretical/precautionary; no documented interaction). Insufficient safety data in pregnancy, lactation, and children. Not a substitute for medical care of joint disease.
Related
Goals: joint-bone · athletic-performance
Lifestyles: senior-60-plus
References
PubMed-indexed citations anchoring the benefit findings above. Effect sizes are reported as published.
- PMID 18417375 · Brien 2008 · Osteoarthritis Cartilage — Knee Osteoarthritis — Pooled Systematic Review
- PMID 16309928 · Kim 2006 · Osteoarthritis Cartilage — Knee Osteoarthritis Pain & Function — Pilot RCT
- PMID 21708034 · Debbi 2011 · BMC Complement Altern Med — Knee Osteoarthritis — Function vs Pain (Mixed RCT)
- PMID 29214616 · Tennent 2017 · US Army Med Dep J — Knee-Pain Prevention in Healthy Trainees — Honest Negative
- PMID 28736511 · Withee 2017 · J Int Soc Sports Nutr — Exercise Recovery / Oxidative Stress — Half-Marathon RCT
- PMID 22525653 · Barmaki 2012 · J Sports Med Phys Fitness — Exercise Muscle Damage & Antioxidant Capacity — RCT
- PMID 37447322 · Toguchi 2023 · Nutrients — Knee Quality of Life in Mild Knee Pain — RCT
Frequently Asked Questions
1. What does the research actually show for MSM and knee osteoarthritis?
The picture is modest and mixed. A systematic review of six DMSO/MSM trials found both MSM trials reported significant pain improvement but called the evidence positive yet not definitive (Brien 2008, PMID 18417375). A pilot RCT found significant WOMAC pain and physical-function improvement at 12 weeks (Kim 2006, PMID 16309928), while another RCT improved WOMAC physical function (14.6 mm, p=0.04) and total score (15.0 mm, p=0.03) but not pain (p=0.08) (Debbi 2011, PMID 21708034). Findings are framed as research in osteoarthritis populations, not as a treatment claim.
2. Are there honest negative findings for MSM?
Yes. In healthy military trainees, 3 g/day MSM did not significantly improve any of the 5 KOOS knee or 6 POMS mood subscales at 30 or 60 days (Tennent 2017, PMID 29214616). And in a half-marathon RCT, the primary time-by-treatment analysis did not reach significance for any oxidative-stress, muscle-damage or pain outcome, though the MSM group showed a within-group Δ > 10 mm drop in muscle and joint pain (Withee 2017, PMID 28736511).
3. Does MSM help with exercise recovery and oxidative stress?
Small trials are suggestive but not consistent. In 18 active men, MSM (50 mg/kg, 10 days) was linked to less post-exercise creatine kinase rise versus placebo (p=0.041) and higher total antioxidant capacity at 2 h and 24 h (p=0.014 and p=0.033) (Barmaki 2012, PMID 22525653). However, the larger half-marathon RCT above did not find significant between-group effects, so the recovery evidence remains preliminary.
4. What dose was used in studies and what is its regulatory status?
Joint-osteoarthritis RCTs generally used about 3 g/day for 12 weeks (Kim 2006 used 3 g twice daily; the mild-knee-pain trial, Toguchi 2023, PMID 37447322, used 2 g/day as 10 tablets), and exercise trials used 3 g/day or 50 mg/kg. In the US, MSM is a lawful dietary-supplement ingredient under DSHEA and the OptiMSM brand holds an independent GRAS determination; the EU permits it as a food supplement but has no authorized health claim. This is educational reference, not a dosing recommendation or medical advice.
Last evidence review: 2026-06-13