Cyclotetrasiloxane
Octamethylcyclotetrasiloxane (D4)
The most restricted of the cyclic siloxanes: ECHA-listed as a Substance of Very High Concern for both PBT/vPvB (persistent, bioaccumulative, toxic) properties and reproductive toxicity. EU law caps combined D4+D5 content at 0.1% in any rinse-off cosmetic product. Increasingly avoided industry-wide, including in leave-on formulas, ahead of anticipated further EU restriction.
Function & Common Use
Solvent / Emollient / Carrier for silicones
Silicone
Historically used in antiperspirants, hair and skin silicone formulations; now largely phased out or present only as a trace impurity in D5-based products
Synthetic
Concentration Limits
No formal limit
Max 0.1% combined with D5 in rinse-off products (REACH Annex XVII Entry 70, effective Feb 2020)
No specific 21 CFR cosmetic limit identified in source checked; EU limit reference: Max 0.1% combined with D5 in rinse-off
No specific MFDS limit identified in source checked; verify if ingredient is used in a Korean functional cosmetic category
Format restriction: Rinse-off: capped at 0.1% combined with D5 under EU REACH; leave-on use under continued SCCS review
Baby restriction: Avoid; not recommended in any baby products
Pregnancy: Avoid; classified as toxic for reproduction (Repr. 1B) under EU CLP; precautionary avoidance recommended
Frequently Asked Questions
Is Cyclotetrasiloxane safe to use in skincare?
Cyclotetrasiloxane has a High concern rating. The most restricted of the cyclic siloxanes: ECHA-listed as a Substance of Very High Concern for both PBT/vPvB (persistent, bioaccumulative, toxic) properties and reproductive toxicity. EU law caps combined D4+D5 content at 0.1% in any rinse-off cosmetic product. Increasingly avoided industry-wide, including in leave-on formulas, ahead of anticipated further EU restriction.
Is Cyclotetrasiloxane allowed in India?
Cyclotetrasiloxane is currently classified as "Permitted" under Indian cosmetics regulations. The maximum permitted concentration is No formal limit.
What is Cyclotetrasiloxane used for in cosmetics?
Cyclotetrasiloxane functions as: Solvent / Emollient / Carrier for silicones. It is commonly found in: Historically used in antiperspirants, hair and skin silicone formulations; now largely phased out or present only as a trace impurity in D5-based products.
Is Cyclotetrasiloxane safe for babies?
Cyclotetrasiloxane has baby/child restrictions: Avoid; not recommended in any baby products. Avoid using products containing this ingredient on infants unless specifically formulated and labelled for baby use.
Regulatory Status
Restricted; SVHC-listed; capped at 0.1% (combined with D5) in rinse-off products; classified as toxic for reproduction
Cosmetic ingredient; standard TGA cosmetic framework applies; no therapeutic goods listing required unless therapeutic claims are made
Not specifically listed as restricted cosmetic ingredient in NHPID source checked; standard Health Canada cosmetic notification applies
EU Annex: EU Annex III; REACH Annex XVII Entry 70; SVHC Candidate List (added 2018)
Identifiers
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