Dimethyl sulfoxide, or DMSO, is a small organosulfur molecule widely used as a polar aprotic solvent. It is not a peptide, and it is not SLU-PP-332.
DMSO is useful in research because it mixes with water and many organic solvents. It is also an experimental variable. Primary studies show that DMSO can change biological readouts depending on concentration, exposure duration, cell model, and endpoint. “Used as a solvent” should not be rewritten as “biologically inert” or “universally compatible.”
FDA has approved specific 50% aqueous dimethyl sulfoxide finished drugs for a narrow urologic use. That approval does not extend to a 3 mL laboratory-solvent vial or any other concentration, grade, route, or purpose.
Evidence state at a glance
| Field | Current record |
|---|---|
| Preferred name | Dimethyl sulfoxide |
| Common abbreviation | DMSO |
| CAS | 67-68-5 |
| Formula | C2H6OS |
| Molecular weight | About 78.13 g/mol |
| Compound type | Small organosulfur molecule; polar aprotic solvent |
| FDA-approved finished-drug context | RIMSO-50, 50% w/w aqueous solution under NDA 017788; generic 50% product approved in 2026 |
| Laboratory evidence | Solvent effects are model-, concentration-, duration-, and endpoint-dependent |
| Catalog status | Concentration, grade definition, water content, sterility status, and lot evidence unresolved |
| Evidence reviewed | August 27, 2026 |
What exactly is DMSO?
PubChem and the NIST Chemistry WebBook identify dimethyl sulfoxide as C2H6OS, CAS 67-68-5, with molecular weight about 78.13 g/mol.[1][2]
The name alone does not define a laboratory product. A vial might contain neat DMSO, an aqueous DMSO solution, an analytical reagent, a cell-culture reagent, a cryopreservation product, an excipient, or a regulated finished drug.
To identify a material, a label and specification should state at least the concentration and basis, grade standard, assay, water content, relevant impurity limits, container, manufacturer, sterility status, and lot.
DMSO is a solvent, and a variable
Solvents can affect the system being studied. A proper experimental record therefore identifies DMSO concentration, exposure time, cell or assay model, solvent-only control, and compatibility with the test compound.
A 2019 study exposed human cardiac and hepatic 3D microtissues to 0.1% DMSO for two weeks. The investigators reported extensive transcriptomic changes and model-dependent effects on other molecular measurements.[8]
An earlier study in primary human and rat hepatocytes found few gene-expression effects up to 0.5% under its conditions and no measured cytotoxicity up to 2%, while observing more expression changes at a higher concentration.[9]
These findings are not contradictory instructions or a universal cutoff. They show that model and duration matter. A concentration that appears noncytotoxic on one endpoint may still change a more sensitive molecular readout in another system.
The responsible conclusion is that DMSO should be controlled and reported as part of the experimental design.
Which DMSO product is FDA approved?
RIMSO-50 is a prescription finished drug under NDA 017788. Its official label identifies a sterile, nonpyrogenic 50% w/w aqueous dimethyl sulfoxide solution and a specific intravesical indication for symptomatic relief of interstitial cystitis.[3]
The same label expressly limits the approval: RIMSO-50 is not approved as safe and effective for other indications, and the label says there is no clinical evidence of effectiveness for bacterial urinary-tract infections.[3]
FDA also approved ANDA 220173 for a generic dimethyl sulfoxide irrigation USP, 50% w/w, on July 7, 2026.[4]
These approvals do not apply to:
- neat or unspecified-concentration DMSO;
- an unidentified laboratory reagent;
- a solvent supplied with or for another research compound;
- topical, injectable, oral, or other unapproved preparations;
- a product that lacks the approved formulation, label, manufacturer, and quality system.
What does the human evidence show?
Human DMSO evidence is formulation-, route-, and condition-specific.
A 1988 controlled crossover trial enrolled 33 participants with interstitial cystitis and reported advantages over saline on selected subjective and objective measures.[5] A 2021 randomized, double-blind, placebo-controlled Japanese study evaluated a named 50% DMSO formulation in 96 participants and reported a statistically significant difference on its primary symptom-index endpoint.[6]
Those findings relate to defined 50% intravesical formulations in a particular condition. They cannot support general claims for DMSO as a laboratory solvent or for a separate vial.
The registry record is not uniformly positive or complete. NCT00317070 enrolled 10 participants, was terminated, and had no posted results when checked August 27, 2026.[7]
Safety evidence remains formulation-specific
The RIMSO-50 label describes hypersensitivity concerns, discomfort and chemical cystitis in its clinical context. It discusses animal lens findings and states that adequate controlled pregnancy studies are lacking and pediatric safety and effectiveness are unestablished. These are product-label boundaries, not a complete risk assessment for every DMSO exposure. Official label, warnings, precautions and adverse reactions.
In the 12-week KRP-116D trial, investigators classified adverse reactions in 29 of 49 active participants and 13 of 47 placebo participants. They described those reactions as mild or moderate. The trial did not report deaths, but its size and duration limit conclusions about uncommon or delayed outcomes. Primary trial, safety section.
The bladder formulation's record cannot establish safety for oral, topical or injected research preparations. Changing the route changes the question being asked. It can also change the relevance of concentration, accompanying ingredients and the tissues exposed.
A cryopreserved-cell case is a different clinical setting
Maral and colleagues described a tonic-clonic seizure shortly after the start of an autologous peripheral-blood-cell infusion involving DMSO-preserved material. Cardiac arrest followed. The authors attributed concern to DMSO-associated toxicity while acknowledging uncertainty about the mechanism. This appraisal is limited to the primary indexed abstract; the full case work-up was not independently examined. Primary report, PMID 30099684.
The abstract is sufficient to identify a serious reported temporal association in a defined clinical setting. It is not sufficient to reconstruct all concurrent exposures, prior risk factors or the reasoning used to exclude alternatives. Those limitations should remain explicit, particularly when a publication's title uses stronger causal wording than can be independently evaluated from the accessible record.
For the same reason, the event cannot be translated into a probability for someone encountering a different DMSO formulation or route. A route-specific safety signal can be important without supporting a cross-route numerical extrapolation.
For the positive symptom-index finding, null week-12 pain result, participant flow and adverse events, see the full KRP-116D trial appraisal.
Why “SLU Solution DMSO” is a problem
The Serum Research catalog product is titled “SLU Solution DMSO (3 mL).” Its body says the vial contains DMSO. The name can nevertheless imply that it contains SLU-PP-332 or is a validated vehicle for that compound.
No official or primary source reviewed for this page establishes that relationship. The DMSO item should not be linked from the SLU-PP-332 evidence page or presented as a preparation system.
The catalog also does not state:
- neat versus aqueous formulation;
- DMSO concentration or concentration basis;
- what “laboratory grade” means;
- assay and water-content limits;
- relevant impurity profile;
- sterility status;
- container compatibility;
- manufacturer and matching lot report.
Until those facts are documented, the product link remains blocked.
Major evidence limitations
- Solvent behavior depends on the solute, matrix, concentration, temperature, protocol, and endpoint.
- DMSO can change biological readouts; it should not be treated as universally inert.
- In-vitro effects cannot be converted into human health claims.
- FDA approval applies to specified 50% finished irrigation products and a narrow labeled use.
- A trial or approved product does not validate a laboratory solvent lot.
- “Laboratory grade” has no useful meaning without a named standard, methods, criteria, results, and lot linkage.
- No source reviewed establishes a relationship between the catalog DMSO and SLU-PP-332.
Frequently asked questions
Is DMSO a peptide?
No. It is a small organosulfur molecule with formula C2H6OS.[1][2]
Is DMSO biologically inert?
Not universally. Primary cell and microtissue studies have measured DMSO-dependent changes, with results varying by model, concentration, duration, and endpoint.[8][9]
Is DMSO FDA approved?
Specific 50% aqueous finished drugs are FDA approved for a defined intravesical indication.[3][4] That does not make every DMSO material or use approved.
Does the RIMSO-50 evidence apply to laboratory DMSO?
No. It applies to a named finished drug, formulation, route, and labeled condition.
Is “SLU Solution DMSO” the compound SLU-PP-332?
No. The live catalog copy identifies DMSO. No reviewed source establishes that the product contains SLU-PP-332.
Does this page validate the Serum Research DMSO vial?
No. Its concentration, grade specification, water content, sterility status, manufacturer, and lot evidence must be documented before a link is added.
Primary and official sources
- PubChem dimethyl sulfoxide record, CID 679
- NIST Chemistry WebBook record for dimethyl sulfoxide
- DailyMed RIMSO-50 label, NDA 017788
- FDA Competitive Generic Therapy approvals list, ANDA 220173, July 7, 2026
- Controlled DMSO crossover study, PMID 3288775
- Randomized placebo-controlled 50% DMSO study, PMID 33580603
- ClinicalTrials.gov NCT00317070
- 0.1% DMSO multi-omics microtissue study, PMID 30874586
- DMSO gene-expression study in primary hepatocytes, PMID 21339255
Further research appraisals
Prepared for Serum Research, a commercial supplier. These research summaries do not independently validate its catalog products and are not instructions for personal medical use.