Is Cyclomethicone safe in cosmetics?
Cyclomethicone has a safety rating of "MODERATE" in our database. EU status: restricted. US status: permitted. 10 toxicological study endpoint(s) are available in our database.
Cyclomethicone
Also known as: D5, 4-04-00-04128, BRN 1800166, EINECS 208-764-9, Silicon SF 1202 (+2 more)
INCI: CYCLOPENTASILOXANE
Cyclomethicone (CAS 541-02-6) is a cosmetic cosmetic ingredient functioning as solvent. NOAEL 3 mg/kg bw/day (PDF-verified against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: restricted, max D4: prohibited; D5+D4: ≤0.1% rinse-off (since Jan 31, 2020); D6: ≤0.1% rinse-off (effective June 6, 2026); D4+D5+D6: ≤0.1% leave-on (effective June 6, 2027). Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety and pharmaceutical data.
Function
solvent
Editorial assessment
MODERATE
Preliminary editorial note — not a computed safety verdict.
Regulatory Status
EU EU Status
restricted
EU Max Conc.
D4: prohibited; D5+D4: ≤0.1% rinse-off (since Jan 31, 2020); D6: ≤0.1% rinse-off (effective June 6, 2026); D4+D5+D6: ≤0.1% leave-on (effective June 6, 2027)
US US Status
permitted
US Notes
Generic INCI Cyclomethicone replaced by Cyclopentasiloxane (D5) or Cyclotetrasiloxane (D4); both EU-restricted in wash-off products
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Cyclomethicone.
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
10 study endpoints found for Cyclomethicone. NOAEL (No Observed Adverse Effect Level) values are used to calculate the Margin of Safety per SCCS methodology.
| Endpoint | Value | Route | Species | Study Type | Source |
|---|---|---|---|---|---|
| NOAEL | =17.8 mg/kg bw/day | inhalation | - | NOAEL study | SCCS Opinion |
| NOAEL | =17.8 mg/kg bw/day | inhalation | - | NOAEL study | SCCS Opinion |
| NOAEL | =17.8 mg/kg bw/day | inhalation | - | NOAEL study | SCCS Opinion |
| NOAEL | =17.8 mg/kg bw/day | inhalation | - | NOAEL study | SCCS Opinion |
| NOAEL | =100 mg/kg bw/d | oral | - | irritation | SCCS Opinion |
| NOAEL | =100 mg/kg bw | oral | - | repeated dose toxicity | SCCS Opinion |
| NOAEL | =100 mg/kg | oral | rat | carcinogenicity | SCCS Opinion |
| NOAEL | =100 mg/kg bw/d | oral | - | irritation | SCCS Opinion |
| NOAEL | =100 mg/kg bw | oral | - | repeated dose toxicity | SCCS Opinion |
| NOAEL | =100 mg/kg | oral | rat | carcinogenicity | SCCS Opinion |
Pre-Calculated Safety Assessment
Conditional — safe only within SCCS limits: reported concentrations safe except hair-styling aerosols and sun-care spray products; oral care not covered; D4 impurity as low as possible
Pre-calculated NOAEL → SED → MoS audit trail for Cyclomethicone across SCCS product categories, with measured dermal absorption where available.
Dermal Penetration Profile
Skin absorption and penetration characteristics of Cyclomethicone, relevant to systemic exposure and MoS calculations.
Absorption %
0.1-0.5%
Penetration Level
surface
Penetration Depth
surface only
Molecular Weight
370.8 Da
Log P
5.2
Systemic Absorption
minimal
Topical Bioavailability
0.05-0.2%
Safety Margin Factor
minimal
Source: CIR Expert Panel
EPA ToxValDB — Toxicity Values
10 toxicity values from EPA ToxValDB (aggregated from CCTE, HPV, ToxRefDB, IRIS, and other regulatory dossiers).
| Endpoint | Value | Species | Route | Duration | Source |
|---|---|---|---|---|---|
| LD50 | >2000 mg/kg | Rabbit | dermal | acute | ECHA |
| LC50 | =8670 mg/m3 | Rat | inhalation | - | ECHA |
| LC50 | >8264.65 mg/m3 | Rat | inhalation | - | ECHA |
| LD50 | >2400 mg/kg | Rat | dermal | - | ECHA |
| LD50 | >2000 mg/kg | Rabbit | dermal | acute | ECHA |
| LD50 | >15360 mg/kg | Rabbit | dermal | acute | ECHA |
| LD50 | >61440 mg/kg | Rat | oral | - | ECHA |
| LD50 | >5000 mg/kg | Rat | oral | - | ECHA |
| LD50 | >20000 mg/kg | Rat | oral | - | ECHA |
| LD50 | >5000 mg/kg | Rat | oral | - | ECHA |
Endocrine Disruptor Evidence (Expanded)
Cross-referenced EDC classifications, mechanism data, and dose-response evidence from EDLists, SIN List, and cosmetic-specific detail sources.
Suspected
Evidence: Moderate
(2019)
Health effects: Yes
Affected pathways: Estrogenic
Regulatory framework: Cosmetics
Source list: II
Cosmetic-Specific Mechanism
Category: other
Receptor targets: ERα (weak), uterotrophic activity
LOEC: 500 mg/kg in vivo (rats)
EU status: restricted (max 0.1% in rinse-off products; banned in wash-off ≥0.1%)
weak agonist
Dose-Response Data Points
| Endpoint | Target | Value | Direction |
|---|---|---|---|
| dermal_SC_cumulative | skin | 63.9 µg/cm²/24h | - |
| dermal_epidermis_cumulative | skin | 29.9 µg/cm²/24h | - |
| Displacement of [3H]-E2 from ER binding | ER | EC50/IC50: EC50 not achievable; weak binding >=10 uM; LOEC: >=10 uM; NOEC: <10 uM mixed | very weak agonist (binding only at very high conc) |
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
10,000 - 100,000 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
Yes (since 27-Jun-2018)
Hazard classification: Restricted (Annex XVII)
SVHC reason: PBT (Article 57d)
Substance of Very High Concern (SVHC)
Included: 27-Jun-2018
PBT (Article 57d); vPvB (Article 57e)
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.
JPKR Japan/Korea Cosmetics
Korea (Restricted): max 19.7
Additional Jurisdictional Restrictions (2)
| Jurisdiction | Status | Max % | Product Type |
|---|---|---|---|
| AU | restricted | - | cosmetics |
| UK | restricted | - | - |
Expanded Dermal Absorption Data
Cross-database dermal penetration: EPA Dryad physics-based, Roberts Mendeley permeation, and SCCS-aggregated measured values.
Aggregated DA Values (5 records across 5 sources)
| Type | DA % | Method | Skin Model | SCCS Ref |
|---|---|---|---|---|
| measured | 1.5% | in_vitro | - | SCCS/0174 |
| measured | 0.05% | in_vitro | - | SCCS/0174 |
| measured | 0.09% | in_vitro | - | SCCS/0174 |
| measured | 0.17% | - | - | SCCS/0174 |
| default | 2.3% | - | - | SCCS/0174 |
Typical Use Concentrations
Reported concentration ranges per product category from SCCS/CIR/industry sources.
| Product Category | Typical Range | Max Reported | Source |
|---|---|---|---|
| Foundation | 5–25 | 50 | CIR Safety Assessment |
| Deodorant | 5–20 | 40 | CIR Safety Assessment |
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Diluent
Emulsifier
Film former
Fragrance
Lubricating agent
Processing aids not otherwise specified
Softener and conditioner
Solvent
Surface modifier
Regulatory List Membership (2)
EU Regulated in Personal Care
IFRA Fragrance Transparency List
Editorial summary
Preliminary editorial summary for Cyclomethicone — not a computed safety verdict. See the sourced toxicological data above.
Regulatory Flags
eu-restricted
d4-eu-banned
d5-d6-restricted-2026-rinseof
d4-d5-d6-restricted-2027-leaveon
vpvb
svhc
reach-2024-1328
volatile-silicone
cyclic-siloxane
environmental-hazard
bioaccumulative
reformulation-urgent
cosmos-prohibited
eu_children_restricted
ifra_fragrance
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to Cyclomethicone by CAS number or substance name.
Studies
20
Lowest NOAEL
17.8
Highest NOAEL
1000
Units vary across source rows: mg/kg bw/day, mg/kg bw/d, mg/kg bw
SCCS Opinion
Dermal Absorption
View details ->| Absorption % | Method | Vehicle |
|---|---|---|
| 1.5% | in_vitro | - |
| 0.05% | in_vitro | - |
| 0.09% | in_vitro | - |
| 0.17% | - | - |
| 2.3% | - | - |
Known Synonyms
D5
4-04-00-04128
BRN 1800166
EINECS 208-764-9
Silicon SF 1202
Dekamethylcyklopentasiloxan
UNII-0THT5PCI0R
Chemical Function
Solvent
Lubricating agent
Regulatory Lists
Canada; pharmaceutical
Europe; Personal care
Europe; Personal care
inert_ingredient; non_food_use; Pesticides
Europe; Other direct contact consumer goods
CEDI
detected; Europe; Other direct contact consumer goods
IFRA Transparency
Europe
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
CHEMBL1885178
Frequently Asked Questions
Is Cyclomethicone allowed in the EU?
Cyclomethicone EU regulatory status: restricted. Maximum allowed concentration: D4: prohibited; D5+D4: ≤0.1% rinse-off (since Jan 31, 2020); D6: ≤0.1% rinse-off (effective June 6, 2026); D4+D5+D6: ≤0.1% leave-on (effective June 6, 2027). This is based on EU Regulation 1223/2009 and its amendments.
What does Cyclomethicone do in cosmetics?
Cyclomethicone functions as: solvent. It is classified as a cosmetic ingredient in our database. CAS number: 541-02-6.
What is the NOAEL for Cyclomethicone?
The NOAEL (No Observed Adverse Effect Level) for Cyclomethicone is =17.8 mg/kg bw/day based on a NOAEL study study via inhalation route in rat. A total of 10 study endpoints are available. Source: SCCS Opinion.
Is Cyclomethicone used outside cosmetics?
Cyclomethicone 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 Cyclomethicone 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
Compare limits across jurisdictions
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