Moderate Cosmetic Ingredient Dermal Penetration

Cyclomethicone

INCI: CYCLOPENTASILOXANE

CAS Number
541-02-6
Function
solvent
Safety Rating
MODERATE

Regulatory Status

🇪🇺 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 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 55 jurisdictions, use the Substance Compliance tool.

Safety Data

Margin of Safety (MoS)
not established
Dermal Absorption
low
Sensitization
none

Calculate MoS for your specific formulation with the MoS Calculator.

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 Verdict

Cyclomethicone (D4/D5/D6 blend) is a volatile solvent providing silky sensory profile in hair and skin products. D4 is fully banned in EU; D5 and D6 are restricted at ≤0.1% in rinse-off products (D6 effective June 2026) and all three restricted in leave-on products at ≤0.1% (effective June 2027) per REACH Regulation 2024/1328. All components classified as SVHC with vPvB properties by ECHA and linked to environmental persistence and animal reproductive toxicity. US permits use without restriction. Reformulation recommended for EU compliance by June 2026-2027.

⚠️
Concern Level: Moderate

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

Frequently Asked Questions

Is Cyclomethicone safe in cosmetics?

Cyclomethicone (D4/D5/D6 blend) is a volatile solvent providing silky sensory profile in hair and skin products. D4 is fully banned in EU; D5 and D6 are restricted at ≤0.1% in rinse-off products (D6 effective June 2026) and all three restricted in leave-on products at ≤0.1% (effective June 2027) per REACH Regulation 2024/1328. All components classified as SVHC with vPvB properties by ECHA and linked to environmental persistence and animal reproductive toxicity. US permits use without restriction. Reformulation recommended for EU compliance by June 2026-2027. The EU classifies Cyclomethicone as "restricted". Safety rating: MODERATE.

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 Margin of Safety for Cyclomethicone?

not established The Margin of Safety (MoS) is calculated using SCCS methodology. A MoS above 100 is generally considered safe. Use the MoS Calculator tool to calculate MoS for your specific formulation and product category.

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