Ingredient review

Cyclotetrasiloxane

INCI: CYCLOTETRASILOXANE

A volatile silicone that gives a silky feel and helps products spread smoothly, but its environmental persistence has raised regulatory concerns in some regions.

beautyskincaresilicone

In plain English

Cyclotetrasiloxane is a type of silicone that evaporates quickly from the skin, leaving a smooth, non-greasy finish. It's often used to help creams and serums glide on easily and to reduce the sticky feeling of other ingredients. Think of it as a temporary helper that disappears after application, so it doesn't build up on your skin.

Review score

Safety, usefulness, and evidence

3.5Good
3.5/ 5

Potentially useful with some tradeoffs

The evidence base is useful, but some claims depend heavily on the formula.

Risk flags are low for most users, though the finished product can still irritate.

Source
synthetic
Evidence
moderate
Irritation
low
Clogging risk
low
How reviews are scored

Quick decision guide

Useful, but context matters

Cyclotetrasiloxane is generally a lower-concern ingredient when the full formula suits your skin.

Plain-English read

Treat this as a practical screening step before you compare products that contain this ingredient.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Cyclotetrasiloxane.
  2. Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
  3. Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.

Score terms in plain English

Irritation risk

low

Less likely to sting, burn, or bother most users, though sensitive skin can still react.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

moderate

There is useful support, but formula details and claim strength still matter.

What it is

A synthetic cyclic silicone (a ring-shaped molecule) that is volatile, meaning it evaporates at skin temperature. It is part of the cyclomethicone family.

How it works

When applied, cyclotetrasiloxane spreads into a thin, even film that temporarily reduces friction. It then evaporates, leaving behind other active ingredients without a heavy residue. This improves the sensory feel of the product.

Pros

Silky, lightweight feel

Creates a smooth, non-greasy finish that many users find pleasant, especially in primers and sunscreens.

Improves product performance

Helps other ingredients spread evenly and reduces the sticky or heavy sensation of some creams and oils.

Cons and cautions

Environmental persistence

Cyclotetrasiloxane does not break down easily in the environment and can accumulate in wildlife, leading to restrictions in some regions.

Regulatory scrutiny

The EU has classified it as a substance of very high concern (SVHC) under REACH, limiting its use in rinse-off products.

Best for

  • People who prefer lightweight, fast-absorbing textures
  • Those looking for a smooth base under makeup

Use caution if

  • Environmentally conscious consumers concerned about persistence
  • Anyone seeking strictly biodegradable or natural formulations

Usage tips

Use in leave-on products where its volatility can be an advantage
Pair with non-volatile emollients to balance feel and longevity
Check product labels if you prefer silicones with lower environmental impact

Safety summary

Low acute toxicity and skin irritation risk for humans. The main concern is environmental persistence, not direct harm to users. Regulatory actions focus on reducing release into the environment.

Research notes

Studies show low dermal absorption and no significant skin sensitization. Environmental monitoring confirms widespread presence in water and air, leading to regulatory restrictions in Europe.

Common label clues

Typical concentration
1% to 15% in leave-on products
Regulatory status
Restricted in rinse-off cosmetic products in the EU (concentration limit of 0.1% or less) due to persistence and bioaccumulation concerns. Allowed in leave-on products but under review.
Common uses
Moisturizers, Primers, Sunscreens, Hair serums, Makeup
Environmental note
This silicone is very persistent in water and air, and can accumulate in aquatic organisms. It is not biodegradable.

Good to know

  • Cyclotetrasiloxane is often abbreviated as D4
  • It is a common component in cyclomethicone blends
  • Some brands have voluntarily phased it out due to environmental concerns

Common questions

What is Cyclotetrasiloxane in beauty products?

Cyclotetrasiloxane is a type of silicone that evaporates quickly from the skin, leaving a smooth, non-greasy finish. It's often used to help creams and serums glide on easily and to reduce the sticky feeling of other ingredients. Think of it as a temporary helper that disappears after application, so it doesn't build up on your skin.

What does Cyclotetrasiloxane do in a beauty product?

When applied, cyclotetrasiloxane spreads into a thin, even film that temporarily reduces friction. It then evaporates, leaving behind other active ingredients without a heavy residue. This improves the sensory feel of the product.

Is Cyclotetrasiloxane safe for most people?

Low acute toxicity and skin irritation risk for humans. The main concern is environmental persistence, not direct harm to users. Regulatory actions focus on reducing release into the environment.

Who should be careful with Cyclotetrasiloxane?

Environmentally conscious consumers concerned about persistence Anyone seeking strictly biodegradable or natural formulations

Research sources

European Chemicals Agency (ECHA) - CyclotetrasiloxaneOpenCosmetic Ingredient Review (CIR) - Safety Assessment of CyclomethiconeOpenPubMed - Dermal absorption of cyclic siloxanesOpen

Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.