Dimethyl Sulfoxide (DMSO) is a colorless, organosulfur compound initially discovered as a by-product of the wood pulp and paper-making process. This compound gained attention in the mid-20th century for its remarkable ability to act as a highly effective solvent, dissolving both polar and nonpolar substances. Historically, it was explored as an anti-inflammatory and pain-relieving agent. It is now approved by the U.S. Food and Drug Administration for treating interstitial cystitis, a chronic bladder condition. DMSO is frequently employed in alternative medicine settings and in transdermal drug delivery systems, where it facilitates the movement of other substances across biological membranes.
Routes of Exposure and Absorption Risks
The most significant characteristic of DMSO is its high permeability, allowing it to move rapidly across the skin barrier and other biological membranes. Dermal absorption is the most common route of entry, occurring when the liquid or gel is applied topically. Inhalation of DMSO vapors is another exposure pathway, particularly in poorly ventilated environments or when heated. Accidental ingestion is also a risk, though less common than topical exposure.
The primary absorption risk associated with DMSO lies in its capacity to act as a carrier molecule, known as enhanced transdermal penetration. As DMSO passes through the skin, it transports any dissolved compounds or impurities directly into the bloodstream. Industrial-grade DMSO, which can contain contaminants like pesticides or heavy metals, poses a heightened toxicity risk. The introduction of these impurities, which otherwise could not cross the skin barrier, can lead to serious health consequences.
Common and Localized Adverse Reactions
Most adverse reactions are mild, transient, and localized to the application site. The most widely recognized side effect is the development of a distinct sulfurous, garlic-like, or oyster-like taste in the mouth. This odor is caused by the metabolic breakdown of DMSO into dimethyl sulfide (DMS), which is then excreted through the breath and skin. This specific body and breath odor can persist for up to 72 hours following application.
Localized skin reactions are common, manifesting as a stinging or burning sensation shortly after application. The skin may display temporary redness (erythema), itching, or hives. Repeated use can sometimes lead to localized skin dryness, thickening, or scaling. These topical effects are generally self-limiting and often relate to the concentration used. Nausea and occasional vomiting are also reported, particularly when DMSO is administered intravenously or in higher concentrations.
Systemic Toxicity and Severe Health Risks
Exposure to high doses of DMSO can lead to widespread systemic toxicity and severe health risks. Severe allergic responses, including anaphylactic reactions, have been documented. Symptoms include a widespread rash, facial swelling, nasal congestion, and difficulty breathing. Such reactions require immediate medical intervention due to the potential for airway compromise.
The compound has also been associated with hematological issues, most notably a dose-dependent breakdown of red blood cells (hemolysis), observed mainly with high-concentration intravenous infusions. DMSO exposure can affect organ systems, with reports of temporary liver and kidney dysfunction following massive intravenous administration. Eye toxicity is a documented concern, stemming from animal studies that showed lenticular changes, though this effect has not been consistently demonstrated in humans. Acute neurological effects may include headache, dizziness, and sedation, seen when the substance is used in large doses. More severe neurotoxicity, including seizures and encephalopathy, has been reported in rare cases, often linked to the rapid infusion of cryopreserved cells that use DMSO as a preservative.
Guidelines for Safe Handling and Risk Mitigation
Minimizing the risk of DMSO toxicity begins with using only high-purity, pharmaceutical-grade product, explicitly avoiding industrial or technical grades that may harbor contaminants. When handling the liquid, work in a well-ventilated area to prevent the inhalation of vapors. Users should wear appropriate personal protective equipment, including chemical-resistant gloves, as common materials like nitrile are easily permeated by DMSO.
Dilution is a practical step for reducing localized and systemic adverse effects, as lower concentrations are better tolerated. Solutions should not be applied to broken, abraded, or infected skin, as this increases the absorption rate and the risk of carrying surface contaminants into the body. Individuals who are pregnant, taking blood thinners, or using sedatives should exercise caution, as DMSO can increase the absorption and effect of certain medications. Adhering to these safety protocols helps mitigate the potential for localized irritation and severe systemic consequences.