Isostearyl Hydroxystearate

What is Isostearyl Hydroxystearate?

Isostearyl Hydroxystearate is a synthetic ester ingredient in cosmetics, formed by combining isostearyl alcohol—a branched fatty alcohol from vegetable sources—with 12-hydroxystearic acid derived from castor oil. It falls into the emollient and skin-conditioning category, appearing in products such as lipsticks, creams, lotions, and foundations. This compound functions by spreading evenly on the skin to form a thin, breathable film that fills surface imperfections, creating a smoother texture and enhancing the sensory feel of formulations. Its branched structure provides a non-oily, velvety finish while helping to limit moisture evaporation from the skin's outer layer. Commonly used for its ability to improve blendability and wear, it supports overall product performance without heaviness, making it suitable for diverse formulations.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1 View on EWG →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Emollient
Softens and smooths skin by filling in surface roughness and improving slip; can also help reduce moisture loss when paired with occlusives and film formers.

Benefits

Delivers a soft, smooth sensation by mimicking skin's natural lipids.

Facilitates easy application with enhanced slip and spreadability.

Assists in maintaining skin's hydration barrier with a lightweight feel.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
People with dry or textured skin seeking smoothing effects.
Anyone with a history of reactions to fatty acid esters.
Individuals preferring non-greasy emollients in daily routines.
Persons sensitive to castor-derived ingredients.
Those with oily or breakout-prone skin due to its non-pore-clogging nature.
Individuals who patch test new products and note discomfort.

Safety Notes

  • Considered safe for use in cosmetics by expert reviews.
  • Shows low potential for irritation or sensitization in formulations.

Frequently Asked Questions about Isostearyl Hydroxystearate

What role does it play in skincare?

It acts as an emollient to soften skin, enhance spread, and help retain moisture with a non-greasy touch.

Is it suitable for acne-prone skin?

Yes, with a comedogenic rating of 0, it poses low risk of contributing to clogs.

How does it differ from other emollients?

Its branched ester form offers superior slip and a matte finish compared to traditional oils.