Is Cyclopentasiloxane banned in Europe?

What the EU does

Restricted, not banned, and getting tighter. Cyclopentasiloxane, the silicone known as D5, has been limited in the EU under REACH since January 31, 2020: a maximum of 0.1% in rinse-off cosmetics such as shampoos and shower gels, because D5 is persistent and bioaccumulative in the environment. That first limit was driven mainly by environmental concern, not acute human-health risk.

The rules then widened. Commission Regulation (EU) 2024/1328 extended the 0.1% cap to leave-on products too, for D5 and D6, taking effect June 6, 2027. So after that date, a moisturizer or serum sold in the EU may contain no more than a trace of D5. Its shorter cousin D4 (cyclotetrasiloxane) goes further: it has been effectively banned from cosmetics since January 1, 2022, over suspected endocrine disruption. The pattern is a restriction escalating toward the vanishing point for D5, and a de facto ban already for D4.

Citation REACH restriction (Regulation (EU) 2018/35) for D4/D5 in rinse-off, effective 31 Jan 2020; Commission Regulation (EU) 2024/1328 (D5/D6 leave-on 0.1% from 6 June 2027); D4 restricted from 2022

What the US does

No comparable federal limit. In the US, cyclopentasiloxane is widely used in cosmetics with no FDA concentration cap. It is a favorite in primers, hair serums, antiperspirants, and foundations because it gives that silky, fast-evaporating slip and then disappears without residue. American formulas routinely contain it at levels far above the EU's 0.1%.

This is a genuine transatlantic gap, and its origin is worth being precise about: the EU restriction is largely environmental (D5 is persistent, bioaccumulative, and toxic to aquatic life), with endocrine concern driving the D4 action, rather than a finding that D5 harms the person wearing it. So a European "silicone-free or trace only" serum and an American silicone-rich one reflect different regulatory priorities, environmental persistence versus formulator freedom, more than a dispute about direct skin safety.

Citation FDA: no specific concentration limit for cyclopentasiloxane in cosmetics

Products that commonly contain it

D5 is the silicone that gives products a silky, quick-drying feel. Common in:

• Hair serums, heat protectants, and anti-frizz sprays
• Face primers, foundations, and BB creams
• Antiperspirants and deodorants
• Moisturizers and "dry-touch" sunscreens

What to look for on a label

On an INCI list, spot it by these names:

• "Cyclopentasiloxane" or "D5"
• "Cyclomethicone" is an older umbrella term that can include D5 and D6
• D4 is "cyclotetrasiloxane"; D6 is "cyclohexasiloxane"
• An EU rinse-off product should hold D5 at 0.1% or less; from June 2027 leave-on products follow

Or skip the squinting: paste the whole ingredient list into our checker and it flags everything in our database. Nothing you paste leaves your browser.

Frequently asked questions

Related ingredients

• Mineral Oil · Another texture ingredient scrutinized more in the EU than the US
• Petrolatum · A slip-and-barrier ingredient with its own EU purity rules

Related reading

• Why Are European Sunscreens Better?