What it is
Cyclotetrasiloxane is a small, volatile cyclic silicone that imparts a silky, dry slip and evaporates after application, leaving a smooth finish without residue. It functions as a spreading agent and carrier in sunscreens and makeup, helping other ingredients distribute evenly. Its use has declined in many markets as formulators shift toward alternative silicones.
Safety & warnings
Cyclotetrasiloxane (D4) has faced regulatory scrutiny over environmental persistence and is restricted in some leave-on cosmetic uses in certain regions, which has reduced its prevalence in newer formulas. On skin it is generally non-irritating and non-comedogenic in typical use.
Origin & sourcing
Synthetic; a manufactured cyclic siloxane produced from silicon-based feedstocks.
Questions everyone asks
What is D4 in skincare?
D4 is cyclotetrasiloxane, a volatile silicone that gives a light, silky slip and evaporates to leave a smooth finish.
Why is cyclotetrasiloxane used less now?
Environmental and regulatory concerns about its persistence have led many formulators to favor alternative silicones.