The Use of Methylsulfonylmethane‐Containing Products in Dermatology: An Evidence‐Based Systematic Review of Safety and Efficacy

Background Methylsulfonylmethane (MSM) is a biologically active sulfur compound that has been implicated in structural protein synthesis and anti‐inflammatory signaling pathways. We conducted a systematic review to evaluate the efficacy and safety of MSM in skin care products and explore the underlying mechanism of action. Methods This review followed PRISMA guidelines and was registered on PROSPERO (CRD420251274679). PubMed, Embase, ClinicalTrials.gov, Cochrane Library, and Ovid/MEDLINE were searched from inception through December 23, 2025. Eligible studies evaluated topical or oral MSM for dermatologic conditions in human participants. Risk of bias was assessed using the Cochrane Risk of Bias 2.0 tool for randomized control trials and the Newcastle–Ottawa Scale for nonrandomized studies. Results Of the 228 records identified, seven studies ( n = 416) met the inclusion criteria: six randomized controlled trials and one case report, in adults with acne vulgaris, erythematous‐telangiectatic rosacea, nail psoriasis, skin aging, and X‐linked ichthyosis. MSM‐containing interventions (both topical and oral) were associated with statistically significant improvements in clinical severity and skin‐related outcomes, including inflammatory lesion counts, erythema, nail severity scores, and measures of skin hydration, elasticity, firmness, texture, and dermal thickness. Reported adverse events were mild and transient, with no serious adverse events or treatment‐related withdrawals. Conclusions The most reliable evidence supports oral MSM for photoaging, moderate support for acne, erythematous‐telangiectatic rosacea, and nail psoriasis, and weakest evidence for X‐linked ichthyosis. Importantly, studies lasting up to 24 weeks did not identify any serious safety concerns.