Is Mercaptopropyltrimethoxysilane safe in cosmetics?
Mercaptopropyltrimethoxysilane has a safety rating of "MODERATE" in our database. EU status: prohibited. US status: permitted.
Moderate
Cosmetic Ingredient
Mercaptopropyltrimethoxysilane
Also known as: 1-Propanethiol, 3-(trimethoxysilyl)-, BRN 2038119, EINECS 224-588-5, gamma-Mercaptopropyltrimethoxysilane, Silane, 3-mercaptopropyltrimethoxy- (+2 more)
INCI: MERCAPTOPROPYLTRIMETHOXYSILANE
Mercaptopropyltrimethoxysilane (CAS 4420-74-0) is a cosmetic cosmetic ingredient functioning as Surface modifier / binding agent - a silane coupling agent that bonds organic. EU Regulation 1223/2009 status: prohibited. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety and pharmaceutical data.
View industrial chemical safety profile for CAS 4420-74-0 →
Auto-generated CPSR Part A draft with source citations
Cross-Vertical Regulatory Divergence
Mercaptopropyltrimethoxysilane is prohibited in EU cosmetics but has active industrial GHS classifications (H302, H312, H317, H319, H411).
Source: Cosmetics: ingredients.eu_status; Chemicals: ghs_classifications.signal_word/hazard_statement_code
Function
Surface modifier / binding agent - a silane coupling agent that bonds organic materials to inorganic surfaces. In cosmetics, used for surface treatment of pigments and fillers to improve dispersibility and skin adhesion.
Safety Rating
MODERATE
Chemistry & Identifiers
IUPAC Name
3-trimethoxysilylpropane-1-thiol
InChIKey
UUEWCQRISZBELL-UHFFFAOYSA-N
Regulatory Status
EU EU Status
prohibited
US US Status
permitted
US Notes
Allowed; no specific prohibition. Used as an indirect additive in cosmetic pigment coatings.
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Mercaptopropyltrimethoxysilane.
Calculate MoS for your specific formulation with the MoS Calculator.
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
100 - 1,000 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
No
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Adhesion/cohesion promoter
Antioxidant
Chemical reaction regulator
Conductive agent
Filler
Hardener
Softener and conditioner
Wetting agent (non-aqueous)
Expert Verdict
Expert safety assessment and concern-level summary for Mercaptopropyltrimethoxysilane.
Regulatory Flags
potential-allergen
Known Synonyms
1-Propanethiol, 3-(trimethoxysilyl)-
BRN 2038119
EINECS 224-588-5
gamma-Mercaptopropyltrimethoxysilane
Silane, 3-mercaptopropyltrimethoxy-
Union carbide A-189
(gamma-mercaptopropyl)trimethoxysilane
Chemical Function
Softener and conditioner
Antioxidant
Filler
Conductive agent
Chemical reaction regulator
Australian Status
AICIS status: listed
Cross-Vertical Safety Context
Same-CAS public records found in pharmaceutical data.
SOURCE
ChEMBL / DrugCentral / FAERS
DB_PHARMA CAS match
Pharmaceutical Data
Same-CAS rows from the pharmaceutical spoke database.
ChEMBL ID
CHEMBL3185147
Frequently Asked Questions
Is Mercaptopropyltrimethoxysilane allowed in the EU?
Mercaptopropyltrimethoxysilane EU regulatory status: prohibited. This is based on EU Regulation 1223/2009 and its amendments.
What does Mercaptopropyltrimethoxysilane do in cosmetics?
Mercaptopropyltrimethoxysilane functions as: Surface modifier / binding agent - a silane coupling agent that bonds organic materials to inorganic surfaces. In cosmetics, used for surface treatment of pigments and fillers to improve dispersibility and skin adhesion.. It is classified as a cosmetic ingredient in our database. CAS number: 4420-74-0.
Is Mercaptopropyltrimethoxysilane used outside cosmetics?
Mercaptopropyltrimethoxysilane also appears in industrial chemical safety and pharmaceutical data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.
Does Mercaptopropyltrimethoxysilane have different safety status in cosmetics vs industrial chemicals?
Mercaptopropyltrimethoxysilane is prohibited in EU cosmetics but has active industrial GHS classifications (H302, H312, H317, H319, H411).
Compliance Tools
Check Mercaptopropyltrimethoxysilane compliance across multiple jurisdictions:
Ingredient Decoder
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82 Allergen Checker
Check for EU declarable fragrance allergens
Substance Compliance
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MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
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