Effectiveness and Safety of Mud Therapy (Pelotherapy) for Musculoskeletal Disorders: A Systematic Review and Meta-Analysis.

The short version

This systematic review and meta-analysis pooled 33 controlled studies with 2,651 adults to ask whether pelotherapy, the application of mineral-rich mud, peat or clay as packs, wraps or full baths, eases musculoskeletal disorders. These include osteoarthritis (joint cartilage wear), rheumatoid arthritis (an autoimmune joint disease), fibromyalgia (widespread pain) and chronic low back pain. Pelotherapy is a traditional naturopathic practice used in spas, balneological centres and clinics in at least 40 countries, and the authors set out to test it against modern standards: pre-registration, risk-of-bias rating and GRADE certainty scoring. The team searched eight databases and trial registers up to April 2026. Included trials enrolled adults with a confirmed musculoskeletal diagnosis, applied mud as the main treatment for 10 to 21 sessions over two to three weeks, and compared it with sham treatment, usual care, waiting lists or nothing. Pain was mostly rated on a 0-100 mm visual analogue scale or a 0-10 numeric scale, and function on questionnaires such as the WOMAC. Two reviewers worked independently and combined results with random-effects statistics. Pain dropped clearly after mud treatment (standardised mean difference -0.74, a moderate-to-large effect, roughly 18.5 mm on the 100 mm scale and above the 15 mm threshold for a meaningful change). The effect was still present at 3 months (-0.61) and at 6 months (-0.49, low certainty). Physical function (-0.69) and quality of life (+0.58 on SF-36) improved as well, with osteoarthritis trials using the WOMAC at -0.82 and rheumatoid arthritis trials using the HAQ at -0.58. Morning stiffness (-0.52) and C-reactive protein, a blood marker of inflammation (-0.44), fell modestly, while the erythrocyte sedimentation rate did not change significantly. Knee osteoarthritis showed the biggest benefit (-0.86), and Dead Sea mud the strongest peloid effect (-0.84). Serious adverse events were no more common than in controls (relative risk 0.98); about 6.5% of mud recipients had mild, short-lived skin redness, largely from heat. The authors note several limits: participants cannot be blinded to mud, peloid type, temperature and protocol varied widely, results differed between trials (I2 = 62% for pain), a correction for possible publication bias lowered the pain estimate to -0.66, most trials came from European spa settings, and safety beyond 12 months is unknown. They call for larger blinded trials with standardised peloids and longer follow-up, and frame pelotherapy as an adjunct to, not a replacement for, drug and physiotherapy care.

Key findings

• This review pooled 33 controlled studies of 2,651 adults with joint and muscle conditions to test pelotherapy, the application of heated mineral mud, peat or clay as packs or baths, and found it reduced pain more than sham, usual care or no treatment (standardised mean difference, a size-of-effect measure, -0.74; moderate certainty).
• The pain benefit was still visible at 3 months (-0.61) and 6 months (-0.49), and physical function (-0.69) and quality of life on the SF-36 (+0.58) improved as well; knee osteoarthritis showed the largest effect (-0.86).
• Serious side effects were no more common than in comparison groups (relative risk 0.98, where 1.0 means no difference); the most frequent problem was mild, short-lived skin redness in about 6.5% of mud recipients, mostly from heat.
• Participants cannot be blinded to mud, the mud type and temperature varied between trials, and there was clear inconsistency in results (I2 = 62%), so the authors adjusted for possible missing studies and obtained a smaller but still meaningful pain effect (-0.66).
• The authors position pelotherapy as an add-on to, not a replacement for, drug and physiotherapy care, and note that safety beyond 12 months and the best standardised mud protocol remain unstudied.

Common questions