Evidence Trace, complete trial record
In plain terms
In plain terms: DMSO (Dimethyl Sulfoxide) shows early signals in human research but the evidence is limited -- small trials, surrogate endpoints, or not yet independently replicated. It is an emerging area, not yet a proven one.
DMSO (Dimethyl Sulfoxide)
C
Limited: small, mixed or unreplicated trials
The endpoint this grade is based on: self_report, Solvent sold as a liquid and a gel, marketed for joint pain and, more recently, taken by mouth for longevity. The randomized trials tested it on the skin for joint and tendon pain, with mixed results, and no trial has tested it against aging.
The evidence as the record states it
Eberhardt et al. (Fortschritte der Medizin, 1995; PMID 8529985): 112 patients with active knee osteoarthritis, 25% DMSO gel versus gel base for 3 weeks, less pain on loading, at rest and on pressure. Simon et al. (Pain, 2009; PMID 19380203): 775 patients with knee osteoarthritis, five arms over 12 weeks; the DMSO vehicle arm did not differ from placebo. Brien et al. (Osteoarthritis and Cartilage, 2008; PMID 18417375): systematic review of four DMSO trials in 681 patients, no definitive conclusion, poor methodology. Kneer et al. (Fortschritte der Medizin, 1994; PMID 8194818): 157 patients with acute shoulder or elbow tendon pain, 10% gel versus gel base for 14 days, 44% pain-free versus 9%. Zuurmond et al. (Acta Anaesthesiologica Scandinavica, 1996; PMID 8721469): 32 patients with acute reflex sympathetic dystrophy, 50% DMSO cream versus cream base, better disease scores. Perez et al. (Pain, 2003; PMID 12670672): 146 patients with complex regional pain syndrome type I, DMSO cream versus oral N-acetylcysteine, no overall difference. Ferraro et al. (Cochrane Database of Systematic Reviews, 2023; PMID 37306570): low-certainty evidence for DMSO in complex regional pain syndrome. Williams et al. (Arthritis and Rheumatism, 1985; PMID 3884019): 84 patients with systemic sclerosis finger ulcers, 2% and 70% DMSO versus saline, no difference. Duimel-Peeters et al. (International Journal of Nursing Studies, 2007; PMID 17553503): massage with DMSO cream did not prevent pressure ulcers better than position changes alone. Kollerup Madsen et al. (F1000Research, 2018; PMID 31489176): systematic review of adverse reactions across 109 studies. Swanson et al. (Journal of Laboratory and Clinical Medicine, 1983; PMID 6854139): DMSO lowered the active metabolite of sulindac. Roth and Shainhouse (Archives of Internal Medicine, 2004; PMID 15477437): DMSO as the absorption enhancer in a topical diclofenac solution. CONTEXT ONLY, NOT GRADED: Salim (Tumor Biology, 1993; PMID 8493453) and Salim (Chemotherapy, 1992; PMID 1591948), single-author randomized trials of oral DMSO after cancer surgery reporting longer survival, never independently repeated.
PMID 8529985 PMID 19380203 PMID 18417375 PMID 8194818 PMID 8721469 PMID 12670672 PMID 37306570 PMID 3884019 PMID 17553503 PMID 31489176 PMID 6854139 PMID 15477437 PMID 8493453 PMID 1591948
Evidence by specific use
Knee osteoarthritis pain, gel applied to the skin
Grade C
The positive trial is the smaller and shorter one. In the larger trial, DMSO was the vehicle for a diclofenac solution and was also given alone as a control arm; alone, it did not beat placebo on pain or function. The systematic review found no definitive conclusion could be drawn from the DMSO trials.
PMID 8529985 PMID 19380203 PMID 18417375
Acute shoulder or elbow tendon pain, gel applied to the skin
Grade C
One multicenter trial, positive: 44% pain-free at 14 days versus 9% on the gel base. It has not been repeated by another group, and a single unrepeated trial is a C on this site.
PMID 8194818
Complex regional pain syndrome type I, cream applied to the skin
Grade C
The placebo-controlled trial was small and positive. The larger trial compared DMSO with oral N-acetylcysteine rather than with placebo and found them about equal. Both trials came from the same Dutch group, and the Cochrane overview rates the evidence low certainty.
PMID 8721469 PMID 12670672 PMID 37306570
Finger ulcers in systemic sclerosis, applied to the skin
Grade D
Tested against saline and not better on any measure. The higher concentration added skin toxicity without adding healing.
PMID 3884019
Pressure ulcer prevention, massaged into the skin
Grade D
Tested in the setting where an earlier pilot had suggested benefit, and the benefit did not appear.
PMID 17553503
Longevity, healthspan or mortality, taken by mouth
Grade D
No human randomized trial has tested DMSO against aging, healthspan or lifespan, by mouth or any other route. The nearest human data are single-author trials of oral DMSO after cancer surgery reporting longer survival in advanced cancer, never repeated in thirty years. They are cited so a reader can find them, and they do not carry a letter.
PMID 8493453 PMID 1591948
Why Grade C Route by_use and not Grade B
Grade C reflects early or limited human evidence -- small trials, surrogate endpoints, or preliminary findings not yet independently replicated. The evidence points in a promising direction but does not yet meet the standard for Grade B. A single well-powered, independently replicated trial with a meaningful endpoint would move this to Grade B or higher.
What this grade covers and what it does not
Grade C, and it rests on the use with the most randomized evidence behind it: DMSO gel applied to the skin for knee osteoarthritis pain. One German trial of a 25% gel in 112 patients found less pain than with the gel base alone (Eberhardt et al., 1995; PMID 8529985). The largest trial run, 775 people with knee osteoarthritis over 12 weeks, included the DMSO solution on its own as one of its five arms and found it no better than placebo on pain or function (Simon et al., 2009; PMID 19380203). A systematic review of the DMSO knee trials concluded that no definitive conclusion can be drawn and flagged possible unblinding (PMID 18417375). A positive trial followed by a larger null one is a replication that failed, which is a C on this site. Pain is reported by the person, which would cap the record at B even if the trials agreed. WHAT THIS GRADE DOES NOT COVER: Aging, healthspan and lifespan, where no human randomized trial has been run at all, so that use is a D. DMSO taken by mouth, which is how it is now marketed for longevity. A series of 1990s trials from a single author, A.S. Salim, gave oral DMSO after cancer surgery and reported longer survival (PMID 8493453, PMID 1591948). Nobody has repeated them in thirty years, and they are listed here as context, not as evidence that moves a letter. The bladder instillation for interstitial cystitis is a prescription drug, RIMSO-50, and it carries its own grade on its own record.
What would move this grade
A well-powered randomized trial with an objective, clinically meaningful primary endpoint and at least one independent replication would support Grade B or higher.
How to track whether this is working
The trials measured pain on a scale and, in the tendon trial, joint mobility. There is no blood marker that reports whether DMSO is working.