MSM, an inexpensive sulfur-containing dietary supplement also made by the body, is used mainly for joint comfort. Its best-supported use, easing knee arthritis pain and improving function, shows a modest, uncertain short-term benefit. Exercise, allergy, skin, hair and cancer claims rest on small, uncontrolled or animal studies. Side effects were mild in trials, with one eye-pressure emergency reported; long-term use is unstudied, and nothing ties MSM to longer life. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Serum creatinine / eGFR | Creatinine about 0.7–1.3 mg/dL (men), 0.6–1.1 mg/dL (women); eGFR 60 mL/min/1.73 m² or higher | Safety check: MSM is cleared in urine |
| ALT | About 7–55 U/L | Safety check, especially with other supplements |
| hs-CRP | No established target; change from the individual's own baseline | Marker MSM is proposed to change (human data inconclusive) |
Cadence: Baseline before starting; symptom scores at 4 and 12 weeks, then every 6 months; creatinine, eGFR and ALT at 12 weeks for doses of 3 g/day or more, then every 12 months; hs-CRP at 12 weeks only if measured at baseline