Question 1

What does Poly- Hydroxystearic Acid do in a cosmetic formula?

Accepted Answer

This ingredient is primarily a dispersant and wetting agent, helping mineral pigments and mineral UV filters spread evenly through oils and emulsions. It improves suspension stability, texture, and film uniformity in tinted products and mineral sunscreens.

Question 2

Is Poly- Hydroxystearic Acid clean?

Accepted Answer

From a clean-beauty perspective, it is generally well tolerated and not a common allergen or sensitizer. The main review point is manufacturing documentation, especially residual processing materials and whether the source feedstocks meet a brand’s standard.

Question 3

Is Poly- Hydroxystearic Acid sustainable?

Accepted Answer

This material is commonly derived from castor-based fatty chemistry, so it can come from renewable plant feedstocks. It is oil soluble and polymeric, but its ester and fatty-acid backbone gives it a better environmental profile than persistent silicone dispersants.

Question 4

Is Poly- Hydroxystearic Acid COSMOS-approved?

Accepted Answer

It can be accepted under COSMOS-natural or COSMOS-organic when made from permitted feedstocks using approved processing, though final status depends on supplier certification. Its fit with Green Chemistry is strongest when plant-derived, efficiently esterified, and used to improve dispersion of mineral filters without persistent silicone carriers.

Question 5

How does Poly- Hydroxystearic Acid work chemically?

Accepted Answer

The molecule is a lipophilic ester-linked polymer built from hydroxylated C18 fatty-acid units, giving it strong affinity for oils and inorganic particle surfaces. Typical use is often around 0.5% to 5% as a dispersant, with higher levels possible in pigment concentrates, and it is generally stable across normal cosmetic pH because it sits mainly in the oil phase.