Is Cysteamine safe in cosmetics?
Cysteamine has a safety rating of "MODERATE" in our database. EU status: permitted. US status: permitted.
Moderate
Active Ingredient
Cysteamine
Also known as: Ethanethiol, 2-amino-, hydrochloride, Ethanethiol, 2-amino-, hydrochloride (1:1), Mercaptamine hydrochloride, 1-Aminoethane-2-thiol hydrochloride, Bekaptan (+8 more)
INCI: CYSTEAMINE HCL
Cysteamine (CAS 156-57-0) is a cosmetic active ingredient functioning as Multi-mechanism depigmenting aminothiol; shifts melanogenesis from eumelanin. EU Regulation 1223/2009 status: permitted, max 5%. 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 156-57-0 →
Auto-generated CPSR Part A draft with source citations
Function
Multi-mechanism depigmenting aminothiol; shifts melanogenesis from eumelanin (dark) toward pheomelanin (lighter) via glutathione/thiol pathway; also inhibits tyrosinase, scavenges dopaquinone intermediate, and chelates iron and copper ions involved in melanin biosynthesis
Safety Rating
MODERATE
Chemistry & Identifiers
EC Number
205-858-1
Regulatory Status
EU EU Status
permitted
EU Max Conc.
5%
US US Status
permitted
US Notes
Permitted in cosmetics under FD&C Act general safety requirements. No FDA OTC monograph or GRASE determination. Approved as prescription drug (cysteamine bitartrate) for nephropathic cystinosis since 1994. No concentration limit for cosmetic use. No CIR safety assessment published.
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Cysteamine.
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
10 - 100 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
No
Expanded Jurisdictional Detail
Additional regulatory detail beyond the 7-jurisdiction summary: Saudi SFDA, Korea MFDS, ASEAN ACD, Japan/Korea, Brazil/India, and cross-jurisdictional restriction entries.
Additional Jurisdictional Restrictions (1)
| Jurisdiction | Status | Max % | Product Type |
|---|---|---|---|
| CN | restricted | 5 | Hair waving/straightening products |
Additional Ingredient Properties
1 property record from structured ingredient metadata.
depigmentation
{"cas_number": "156-57-0", "ingredient_class": "combined_mechanism", "primary_mechanism_of_action": "Synthetic or isolated bioactive with melanin reduction properties", "secondary_mechanisms": "Variable", "molecular_target": "other", "tyrosinase_inhibition_IC50_uM": "varies", "tyrosinase_inhibition_type": "competitive", "melanin_reduction_pct_in_vitro": "25-45", "melanin_reduction_pct_clinical": "…
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Antioxidant
Hair waving or straightening
Reducing agent
Expert Verdict
Expert safety assessment and concern-level summary for Cysteamine.
Regulatory Flags
contact-sensitizer
developmental-toxicity
rinse-off-only
japan-restricted
no-sccs-opinion
no-cir-assessment
occupational-risk
clastogenic-potential-flagged
Known Synonyms
Ethanethiol, 2-amino-, hydrochloride
Ethanethiol, 2-amino-, hydrochloride (1:1)
Mercaptamine hydrochloride
1-Aminoethane-2-thiol hydrochloride
Bekaptan
EINECS 205-858-1
Ethylamine, 2-mercapto-, hydrochloride
Mercaptoethylamine hydrochloride
NSC 21116
eta-Mercaptoethylamine hydrochloride
beta-Mercaptoaethylamin chlorhydrat
Cysteaminhydrochlorid
UNII-IF1B771SVB
Chemical Function
Antioxidant
Reducing agent
Hair waving or straightening
Regulatory Lists
pharmaceutical
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.
Compound
CYSTEAMINE HYDROCHLORIDE
ChEMBL ID
CHEMBL1256137
Max Phase
4
Adverse Event Associations
22
Frequently Asked Questions
Is Cysteamine allowed in the EU?
Cysteamine EU regulatory status: permitted. Maximum allowed concentration: 5%. This is based on EU Regulation 1223/2009 and its amendments.
What does Cysteamine do in cosmetics?
Cysteamine functions as: Multi-mechanism depigmenting aminothiol; shifts melanogenesis from eumelanin (dark) toward pheomelanin (lighter) via glutathione/thiol pathway; also inhibits tyrosinase, scavenges dopaquinone intermediate, and chelates iron and copper ions involved in melanin biosynthesis. It is classified as a Active Ingredient in our database. CAS number: 156-57-0.
Is Cysteamine used outside cosmetics?
Cysteamine 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.
Compliance Tools
Check Cysteamine compliance across multiple jurisdictions:
Ingredient Decoder
Paste a full ingredient list for instant analysis
82 Allergen Checker
Check for EU declarable fragrance allergens
Substance Compliance
Check compliance across multiple jurisdictions
MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
Compare limits across jurisdictions
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Cysteamine HCl
Good
Chemical family
Skin Brightening
P-PHENETIDINE
Moderate
Chemical family
Hair Dyeing
CYSTEINE HCL
Good
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