Silicones show up in an enormous share of moisturizers, primers and sunscreens — including several reviewed on this site, from Neutrogena Hydro Boost to Supergoop Unseen Sunscreen to Dr.Jart+ Cicapair. They're also one of the most confidently miscategorized ingredient groups in skincare, caught between two competing claims: that they clog pores, and that they're an environmental hazard. Both claims contain a real, narrow truth buried inside an overgeneralization. Here's the actual distinction.
- Dimethicone, the most common skincare silicone, has a comedogenic rating of 1 out of 5 — the dermatology literature does not support the widespread claim that silicones clog pores.
- The Cosmetic Ingredient Review panel considers dimethicone safe as used, partly because its large molecular size means it isn't meaningfully absorbed into skin.
- The environmental concern is real, but it applies specifically to cyclic silicones (D4, D5, D6) — not to dimethicone or other linear silicones, which is a distinction most 'silicones are bad' claims skip entirely.
- The EU has restricted D4 and D5 in rinse-off products since 2020, with D5 capped at 0.1% in leave-on products from June 2027, based on persistence and bioaccumulation data, not skin-safety data.
- Silicones create the smooth, blurring, 'silky' texture in primers and many moisturizers precisely because they sit on the surface as a film — understanding that explains both their benefit and their main limitation.
What silicones actually are
'Silicone' isn't one ingredient — it's a category of synthetic polymers built on a silicon-oxygen backbone, and the specific type matters more than the category label. Dimethicone is by far the most common in skincare: a linear silicone used as an emollient and skin protectant, creating the smooth, silky, blurring texture in primers, sunscreens and many moisturizers.
Cyclic silicones — cyclopentasiloxane (D5), cyclotetrasiloxane (D4) and cyclohexasiloxane (D6) — are a chemically different subgroup, often used for their fast-evaporating, lightweight feel in primers and hair products. This distinction between linear and cyclic silicones is the entire basis for the honest version of both major silicone controversies.
What silicones are actually good at
- Creating a smooth, blurring, 'photo filter' finish — this is why primers and color-correcting products (like tinted sunscreens or cica color correctors) lean on them heavily.
- Sealing in moisture as a breathable occlusive, without the heavy or greasy feel of oil-based occlusives like petrolatum or shea butter.
- Improving the spreadability and after-feel of actives and sunscreen filters, which is part of why many chemical sunscreens use them to offset the tacky feel some UV filters have on their own.
- Providing a protective barrier that can support skin barrier function in dry or compromised skin, without the pore-clogging risk sometimes assumed.
Frequently asked questions
Does dimethicone clog pores?
No, not according to the comedogenicity research — dimethicone carries a rating of 1 out of 5, which is low. It sits on the skin's surface as a breathable film rather than penetrating into pores, and the Cosmetic Ingredient Review panel has assessed it as safe as used in cosmetics.
Are silicones bad for the environment?
Specific cyclic silicones — D4, D5 and D6 — are genuinely a concern and are restricted in the EU because they're persistent and can bioaccumulate in aquatic environments. This doesn't apply to dimethicone or other linear silicones, which aren't part of these restrictions. Checking for cyclopentasiloxane or similar cyclic names on a label is the precise way to address this concern.
Why do primers and color-correcting creams use so much silicone?
Silicones create a smooth, blurring, light-diffusing finish on skin, which is exactly the effect a primer or color-corrector is going for. That same property is why products like tinted sunscreens and color-correcting treatments lean heavily on a silicone base.
Is silicone-free skincare actually better?
Not inherently — 'silicone-free' is a broader claim than the evidence supports, since the real comedogenicity and environmental concerns apply to specific silicone types, not the whole category. If a particular product with silicone in it breaks you out, that's valid personal feedback, but it doesn't mean silicones generally are the problem.
What's the difference between dimethicone and cyclopentasiloxane?
Dimethicone is a linear silicone commonly used as a moisturizing, film-forming emollient with an established safety and low-comedogenicity profile. Cyclopentasiloxane (D5) is a cyclic silicone, chemically different, prized for a lightweight, fast-evaporating feel — but it's the type facing real environmental restrictions in the EU, unlike dimethicone.
Sources & further reading
- "Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear" — Fulton et al., PubMed
- "Amended Safety Assessment of Dimethicone, Methicone, and Substituted Methicone Polymers" — Cosmetic Ingredient Review
- "D4/D5 regulation update: cyclosiloxanes in the EU" — UL Prospector
This article is written and edited by the Pure Moonlight team, grounded in the peer-reviewed and clinical sources listed above and cross-checked against our ingredient analyzer's database. It is not a substitute for advice from a dermatologist or doctor.