Methylsulfonylmethane (MSM)

Methylsulfonylmethane (MSM) is a sulfur compound sold as a supplement for slowing aging and extending lifespan. No convincing benefit for this use has been shown: there is no quality evidence base for an effect of MSM on aging or longevity in people. On its own, at usual doses, it is well tolerated. What actually affects a longer healthy life is not smoking, regular physical activity, sleep, and keeping blood pressure, blood sugar, and weight in check with your doctor.

MSM is sold as «anti-inflammatory for joints» in osteoarthritis. Brien 2011 systematic review (4 RCTs, 189 patients with knee OA) showed statistically significant WOMAC and VAS pain reduction at 3-6 g/day × 12 weeks, but clinical significance is minimal (effect 3-4 times smaller than mean NSAID effect). All trials are small, heterogeneous in MSM dose and form, with high risk of bias. OARSI 2019, NICE NG226 2022, ESCEO 2014 and EULAR 2018 do not include MSM in osteoarthritis recommendations. First-line for knee OA is non-pharmacological (weight loss at BMI>25, quadriceps-strengthening exercise), topical NSAIDs (diclofenac gel), paracetamol as option, intra-articular steroid if insufficient effect. If MSM was recommended as a substitute for topical NSAIDs and exercise therapy, consider seeking a second opinion from a rheumatologist.

Methylsulfonylmethane (MSM) is a sulfur source that supplement makers market for skin radiance and stronger hair and nails. No convincing benefit for this use has been shown: there are no good-quality studies on skin, hair, or nails specifically, and the claims rest on marketing rather than an evidence base. Taken for this purpose the compound is well tolerated and carries no notable risk. What actually helps skin, hair, and nails is balanced nutrition and correcting a confirmed deficiency (iron, protein, zinc), which is worth discussing with a doctor.