DMSO (dimethyl sulfoxide) is a colorless liquid solvent with an unusual ability to penetrate skin rapidly and carry other substances with it into the body. This property has made it both a legitimate medical tool and a source of persistent hype. In reality, DMSO has only one FDA-approved use in humans, though its biological effects span pain relief, inflammation reduction, and enhanced drug delivery.
How DMSO Gets Into Your Body
DMSO’s defining trait is how easily it crosses biological barriers. If you spill it on your hand, you’ll taste garlic on your tongue within minutes. That garlic flavor comes from a byproduct your body creates as it metabolizes the compound, and the speed of that reaction demonstrates just how quickly DMSO moves through skin and into the bloodstream.
It works by disrupting the outermost layer of skin, called the stratum corneum, which normally acts as a tight barrier. DMSO interacts with the fats between skin cells, temporarily loosening their packing arrangement so molecules can slip through more easily. It also creates tiny solvent pockets within the tissue that pull dissolved substances deeper, and it boosts the concentration of whatever is dissolved in it at the skin’s surface. The net effect: DMSO moves through skin efficiently and drags other small molecules along for the ride.
This “carrier” property is both DMSO’s greatest strength and its biggest risk. It can deliver helpful drugs through the skin, but it can just as easily transport harmful chemicals into your bloodstream.
The One FDA-Approved Use
DMSO has a single approved medical application in the United States: treating interstitial cystitis, a chronic and painful bladder condition. Under the brand name Rimso-50, a 50% DMSO solution is delivered directly into the bladder through a catheter, left in place for about 15 minutes, and then drained. Treatments typically happen every two weeks until symptoms improve, then taper to a less frequent schedule.
DMSO is one of the most commonly used bladder instillation treatments for this condition, sometimes mixed with other medications. Its anti-inflammatory properties and ability to penetrate the bladder lining make it effective for reducing the pain and urgency that define interstitial cystitis. This is not a home treatment. It’s performed in a clinical setting.
Anti-Inflammatory and Antioxidant Effects
Beyond its role as a carrier, DMSO has direct biological activity. At low concentrations, it acts as a free radical scavenger, neutralizing highly reactive molecules called hydroxyl radicals that damage cells and drive inflammation. Its metabolic byproduct, dimethyl sulfide (the compound responsible for that garlic taste), scavenges a different type of free radical: reactive oxygen. Together, DMSO and its byproduct offer a two-layer antioxidant effect.
DMSO also interacts strongly with the fatty membranes surrounding cells, which contributes to both its anti-inflammatory and neuroprotective effects. These properties are well documented in lab settings, though translating them into reliable clinical treatments has proven more complicated.
Does It Actually Reduce Pain?
DMSO has a long reputation as a topical pain reliever, particularly for joint pain and arthritis. The evidence, however, is underwhelming. A systematic review examining randomized controlled trials of DMSO for osteoarthritis (covering 326 patients total) found that while two of three studies showed a statistically significant reduction in pain compared to controls, the actual improvement was not clinically meaningful. The meta-analysis found an average pain reduction of just 6.34 mm on a 100 mm pain scale, a difference so small it wouldn’t be noticeable to most people. The overall effect was neither statistically nor clinically significant.
In short, DMSO may produce a mild warming or soothing sensation when applied to skin, but current evidence does not support it as an effective standalone pain treatment for arthritis.
How It Enhances Drug Delivery
Where DMSO shows the most clinical promise is as a vehicle for getting other drugs through the skin. It has been used to increase the penetration of chemotherapy agents for treating superficial skin cancers and warts, pushing the medication through the outer skin layer, depositing it in deeper tissue, and promoting transport into local blood vessels. This approach allows higher drug concentrations to reach the target area without requiring injections or pills.
This same mechanism is why DMSO appears in some compounding pharmacies as an ingredient in custom topical formulations. It can make medications that wouldn’t normally absorb well through skin become effective as topical treatments.
Side Effects and Skin Irritation
The most universal side effect of DMSO is the garlic-like taste and body odor it produces, which can persist for hours after skin application. Your body converts DMSO into dimethyl sulfide, a sulfur compound that gets exhaled through your lungs and secreted through your pores.
Skin irritation depends heavily on concentration. Solutions above 60% can cause redness and peeling of the outer skin layer, especially with prolonged contact. In studies, exposures of three hours to 60% DMSO or brief exposures to 90% concentrations produced visible clinical signs of irritation. Repeated daily exposure at moderate concentrations (60 to 73%) also showed a cumulative effect, with skin becoming progressively more vulnerable rather than adapting. Lower concentrations are generally tolerated without significant irritation.
Early clinical trials in the 1960s raised concerns about eye-related side effects, which prompted the FDA to halt most DMSO research in 1965. The agency later classified DMSO in its safest solvent category, but those initial safety concerns significantly slowed its path toward broader medical approval.
The Carrier Effect Cuts Both Ways
DMSO’s ability to transport molecules through skin is indiscriminate. It will carry beneficial drugs into your body, but it will also carry anything else dissolved in it or sitting on your skin. Insect repellent, sunscreen chemicals, cleaning product residue, or any other substance on your hands could potentially be pulled into your bloodstream if DMSO is applied over it.
DMSO also amplifies the effects of certain drugs when used alongside them. It potentiates the activity of blood thinners like heparin, insulin, corticosteroids, and atropine, both through skin absorption and systemically. It also has mild cholinesterase-inhibiting activity, meaning it should never be combined with organophosphate pesticides or similar compounds. In veterinary medicine, a horse died from mercury poisoning after DMSO was mixed with mercury-containing compounds and applied to its skin. The DMSO carried a lethal dose of mercury straight into the animal’s bloodstream.
The takeaway: your skin must be completely clean before any DMSO application, and you should be cautious about combining it with other topical products.
Industrial vs. Pharmaceutical Grade
One of the most practical dangers with DMSO is product purity. Industrial-grade DMSO, which is widely available and inexpensive, is not manufactured for human use. The equipment used to produce it often processes pesticides and other toxic chemicals, making contamination essentially unavoidable. Because DMSO is such an effective solvent and skin-penetrating agent, any contaminants in the product get delivered directly into your body.
Pharmaceutical-grade DMSO (99.9% purity) is produced under controlled conditions specifically to avoid this problem. If you’re using DMSO for any purpose involving skin contact, the grade matters enormously. A bargain bottle of industrial DMSO could contain trace pesticides, heavy metals, or other manufacturing residues that DMSO will efficiently transport through your skin and into your bloodstream.