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Annex II Entry 338 27/10/2010

Dimethyl sulfoxide (INN)

Dimethyl sulfoxide (INN) is listed in Annex II as a prohibited substance for cosmetic products placed on the EU market.

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Prohibited substance— Annex II, EU Regulation 1223/2009
Entry: 338

Chemical identity and properties

PubChem 2D chemical structure for CAS 67-68-5
CAS 67-68-5PubChem CID 679

Dimethyl Sulfoxide

Dimethyl sulfoxide is a 2-carbon sulfoxide in which the sulfur atom has two methyl substituents. It has a role as a geroprotector, an alkylating agent, a non-narcotic analgesic, a MRI contrast agent, a polar aprotic solvent, a radical scavenger, an antidote and an Escherichia coli metabolite. It is a volatile organic compound and a sulfoxide. — ChEBI

IUPAC name
methylsulfinylmethane
Molecular formula
C2H6OS
Molecular weight
78.14 g/mol
Exact mass
78.01393598 Da
XLogP3
-0.6
Topological polar surface area
36.3 Ų
Hydrogen-bond donors
0
Hydrogen-bond acceptors
2
Covalent units
1
Defined stereocentres
0

Also known as

DMSOMethyl sulfoxideDimethyl sulphoxideDimethylsulfoxidesulfinylbismethaneDemasorbDomosoMethane, sulfinylbis-
16 more reported names
DemsodroxDromisolDeltanDemavetDemesoDolicurHyadurInfiltrinaSomiprontDimexideDurasorbSyntexanDermasorbDimethyl sulfur oxideDoligurDipirartril-tropico
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External database identifiers

Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Record details

Chemical name

Dimethyl sulfoxide (INN)

Regulatory information

Regulation

(EC) 2009/1223

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Identified ingredients

Key data

CAS
67-68-5
EC
200-664-3
Annex
II
Entry number
338

Inventory links for Dimethyl sulfoxide (INN)

Inventory Restriction reference
Ref 85731

DMSO

CAS: 67-68-5
EC: 200-664-3

Direct matches are limited for this record, so nearby entries from Annex II are shown as well.

Annex II 343
Nearby record in the same annex

Dioxane

CAS: 123-91-1
EC: 204-661-8

What Annex II means for Dimethyl sulfoxide (INN)

Dimethyl sulfoxide (INN) is listed as a prohibited substance under Annex II of EU Cosmetics Regulation 1223/2009 and must not be intentionally added. Article 17 separately addresses unintended small quantities that are technically unavoidable under good manufacturing practice and compatible with the Article 3 safety requirement.

Formulators must screen their ingredients and raw materials to ensure none contain this substance. Suppliers should provide documentation confirming absence when requested.

This record is linked to 1 CosIng inventory ingredient for name and identifier cross-reference. The page also surfaces 12 related annex records with overlapping identifiers, annex logic or naming patterns.

Compliance checklist

  • Verify this substance is absent from all raw materials and finished formulations.
  • Request absence confirmation or CoA from raw material suppliers.
  • Document the screening result in the Product Information File (PIF).

Frequently asked questions

Yes. Dimethyl sulfoxide (INN) is listed in Annex II of EU Cosmetics Regulation 1223/2009 and is prohibited as an intentionally added cosmetic ingredient. Article 17 provides a narrow exception for unintended small quantities that are technically unavoidable under good manufacturing practice, provided the product remains safe under Article 3.

CAS 67-68-5 is the unique numerical identifier assigned to Dimethyl sulfoxide (INN) by the Chemical Abstracts Service. In cosmetic compliance work, the CAS number is used to cross-reference the substance across regulatory databases, raw material specifications and safety assessment reports. Multiple EU annex entries may share the same CAS number if the same substance appears under different conditions or in different annexes.

Use the INCI Checker tool on this site to paste your full ingredient list (INCI) and scan it against all Annex II–VI entries. The tool highlights any ingredients that match restricted, prohibited or allergen-flagged records. This is useful for rapid compliance screening of finished product formulas or raw material declarations.
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Source note for Annex II record Dimethyl sulfoxide (INN)

This page summarizes one Annex II record for Dimethyl sulfoxide (INN) from public European Commission cosmetic materials and adds linked inventory or identifier matches when available.

Use this record page to review Annex II conditions for Dimethyl sulfoxide (INN), but confirm any final regulatory decision against the current official annex wording and source files.

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