Question 1

What does Dimethicone/Mercaptopropyl Methicone Copolymer do in a cosmetic formula?

Accepted Answer

This ingredient is primarily a conditioning film-former for hair and skin, used to add slip, gloss, softness, and a water-resistant feel. Thiol-functional side groups can improve adhesion to keratin and help anchor conditioning effects.

Question 2

Is Dimethicone/Mercaptopropyl Methicone Copolymer clean?

Accepted Answer

This ingredient has clean-standard friction because it is a synthetic, persistent polymer rather than because it is usually irritating. Residual monomers, volatile cyclic species, and overall biodegradability are the main quality-control concerns.

Question 3

Is Dimethicone/Mercaptopropyl Methicone Copolymer sustainable?

Accepted Answer

This material is made through synthetic polymer chemistry using mineral-derived silicon and petrochemical feedstocks. It is not readily biodegradable and may persist in water and sediment, which weakens its sustainability profile.

Question 4

Is Dimethicone/Mercaptopropyl Methicone Copolymer COSMOS-approved?

Accepted Answer

This ingredient is not permitted in COSMOS-natural or COSMOS-organic products because synthetic organosiloxane polymers fall outside the standard’s allowed ingredient categories. It has weak Green Chemistry alignment due to nonrenewable feedstocks and persistence, even though it can perform at low use levels.

Question 5

How does Dimethicone/Mercaptopropyl Methicone Copolymer work chemically?

Accepted Answer

The molecule is a high-molecular-weight organosiloxane copolymer with flexible Si-O-Si segments and pendant thiol groups that can interact with keratinous surfaces. It is used at low levels in anhydrous or emulsion systems, is generally stable across common cosmetic pH ranges, and requires impurity control for residual monomers and volatile cyclic species.