Is Cyclopentasiloxane safe in cosmetics?
Cyclopentasiloxane 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.
Cyclopentasiloxane
Also known as: D5, 4-04-00-04128, BRN 1800166, EINECS 208-764-9, Silicon SF 1202 (+2 more)
INCI: CYCLOPENTASILOXANE
Cyclopentasiloxane (CAS 541-02-6) is a cosmetic cosmetic ingredient functioning as solvent, emollient, volatile carrier, conditioning agent. NOAEL 3 mg/kg bw/day (PDF-verified against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: restricted, max ≥0.1% w/w prohibited in all consumer and professional products under EU Reg 2024/1328; enforcement June 6, 2026. 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 541-02-6 →
Auto-generated CPSR Part A draft with source citations
Function
solvent, emollient, volatile carrier, conditioning agent
Safety Rating
MODERATE
Regulatory Status
EU EU Status
restricted
EU Max Conc.
≥0.1% w/w prohibited in all consumer and professional products under EU Reg 2024/1328; enforcement June 6, 2026
US US Status
permitted
US Notes
No FDA restriction; no US cyclomethicone ban as of 2026; CIR assessed safe at use concentrations
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Cyclopentasiloxane.
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
10 study endpoints found for Cyclopentasiloxane. 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_vision_codex |
| NOAEL | =17.8 mg/kg bw/day | inhalation | - | NOAEL study | SCCS_vision_codex |
| NOAEL | =17.8 mg/kg bw/day | inhalation | - | NOAEL study | SCCS_vision_codex |
| NOAEL | =17.8 mg/kg bw/day | inhalation | - | NOAEL study | SCCS_vision_codex |
| NOAEL | =100 mg/kg bw/d | oral | - | irritation | SCCS_vision_codex |
| NOAEL | =100 mg/kg bw | oral | - | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =100 mg/kg | oral | rat | carcinogenicity | SCCS_vision_codex |
| NOAEL | =100 mg/kg bw/d | oral | - | irritation | SCCS_vision_codex |
| NOAEL | =100 mg/kg bw | oral | - | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =100 mg/kg | oral | rat | carcinogenicity | SCCS_vision_codex |
Pre-Calculated Safety Assessment
Pre-calculated NOAEL → SED → MoS audit trail for Cyclopentasiloxane across SCCS product categories, with measured dermal absorption where available.
Dermal Penetration Profile
Skin absorption and penetration characteristics of Cyclopentasiloxane, 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
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 IUCLID |
| LC50 | =8670 mg/m3 | Rat | inhalation | - | ECHA IUCLID |
| LC50 | >8264.65 mg/m3 | Rat | inhalation | - | ECHA IUCLID |
| LD50 | >2400 mg/kg | Rat | dermal | - | ECHA IUCLID |
| LD50 | >2000 mg/kg | Rabbit | dermal | acute | ECHA IUCLID |
| LD50 | >15360 mg/kg | Rabbit | dermal | acute | ECHA IUCLID |
| LD50 | >61440 mg/kg | Rat | oral | - | ECHA IUCLID |
| LD50 | >5000 mg/kg | Rat | oral | - | ECHA IUCLID |
| LD50 | >20000 mg/kg | Rat | oral | - | ECHA IUCLID |
| LD50 | >5000 mg/kg | Rat | oral | - | ECHA IUCLID |
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/VCRP |
| Deodorant | 5–20 | 40 | CIR/VCRP |
Additional Ingredient Properties
10 property records from structured ingredient metadata.
acne
{"cas_number": "541-02-6", "anti_acne_mechanism": "anti_inflammatory", "comedogenicity_rating_0_to_5": "0", "acne_type_efficacy": "inflammatory", "sebum_reduction_pct_clinical": "0-5", "prescription_required_usa": "No", "otc_drug_monograph_category": "No", "max_otc_concentration_pct": "No limit", "japan_quasi_drug_anti_acne": "No", "korea_functional_cosmetic_acne": "No", "eu_cosmetic_restriction_a…
anti_pollution
{"cas_number": "541-02-6", "ingredient_class": "anti_pollution", "primary_mechanism": "film_forming_barrier", "pollution_types_targeted": "PM2_5", "IR_A_protection": "no", "visible_light_protection": "no", "digital_screen_protection_claim": "no", "PAH_neutralization": "no", "ozone_protection": "no", "mitochondrial_protection": "no", "Nrf2_activation": "no", "AhR_pathway_modulation": "no", "NF_kB_i…
baby_pediatric
{"cas_number": "541-02-6", "ingredient_class": "other", "pediatric_safety_rating": "good", "minimum_age_months": "0", "neonatal_safe": "yes", "premature_infant_safe": "yes", "skin_barrier_maturity_consideration": "D5 silicone, volatile", "transepidermal_absorption_risk_pediatric": "very_low", "dose_per_kg_body_weight_concern": "Non-absorbed polymer", "skin_surface_area_to_weight_ratio_relevance": …
comedogenicity_detail
{"comedogenicity_rating": "0", "irritancy_rating": "0", "skin_type_suitability": "all,oily,combination,normal,acne-prone", "acne_safe": "yes", "source": "Volatile silicone"}
concentration
{"min_concentration_pct": "5.0", "max_concentration_pct": "30.0", "typical_concentration_pct": "15.0", "product_type": "Hair Serum", "function_at_concentration": "Lightweight conditioning", "source": "CIR Safety Assessment"}
deodorant
{"cas_number": "541-02-6", "ingredient_class": "other", "mechanism_of_action": "other", "antiperspirant_efficacy_sweat_reduction_pct": "0", "deodorant_efficacy_hours": "0", "odor_reduction_pct": "0", "bacteriostatic": "no", "bactericidal": "no", "microbiome_impact": "neutral", "axillary_microbiome_effect": "varies by ingredient", "MIC_value_if_antimicrobial": "varies", "astringency_level": "varies…
dermal_absorption
{"molecular_weight_da": "370.8", "log_p_value": "5.2", "skin_penetration_level": "surface", "penetration_depth": "surface only", "absorption_pct": "0.1-0.5", "systemic_absorption": "minimal", "penetration_enhancer": "no", "occlusion_effect": "yes", "vehicle_dependent": "no", "skin_barrier_effect": "neutral", "bioavailability_topical_pct": "0.05-0.2", "safety_margin_factor": "minimal", "source": "C…
hair_care
{"hair_function": "conditioning", "hair_type_suitability": "fine/medium", "curl_pattern_suitability": "all", "porosity_suitability": "low", "protein_sensitivity": "neutral", "moisture_protein_balance": "no", "cg_method_approved": "non-water-soluble", "silicone_type": "not-a-sulfate", "sulfate_type": "no", "drying_alcohol": "no", "fatty_alcohol": "yes", "heat_protectant": "yes", "color_safe": "neut…
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
Expert Verdict
Expert safety assessment and concern-level summary for Cyclopentasiloxane.
Regulatory Flags
svhc
vpvb
endocrine-disruptor
eu-restricted-2026
reach-reg-2024-1328
bioaccumulative
environmental-hazard
volatile-silicone
cyclic-siloxane
pops-candidate
reformulate-required
ifra_fragrance
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to Cyclopentasiloxane by CAS number or substance name.
Studies
20
Lowest NOAEL
17.8
Highest NOAEL
1000
Units vary across source rows: mg/kg bw/d, mg/kg bw, mg/kg
SCCS_vision_codex
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 Cyclopentasiloxane allowed in the EU?
Cyclopentasiloxane EU regulatory status: restricted. Maximum allowed concentration: ≥0.1% w/w prohibited in all consumer and professional products under EU Reg 2024/1328; enforcement June 6, 2026. This is based on EU Regulation 1223/2009 and its amendments.
What does Cyclopentasiloxane do in cosmetics?
Cyclopentasiloxane functions as: solvent, emollient, volatile carrier, conditioning agent. It is classified as a cosmetic ingredient in our database. CAS number: 541-02-6.
What is the NOAEL for Cyclopentasiloxane?
The NOAEL (No Observed Adverse Effect Level) for Cyclopentasiloxane 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_vision_codex.
Is Cyclopentasiloxane used outside cosmetics?
Cyclopentasiloxane 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 Cyclopentasiloxane 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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