Hydroxystearic Acid

What is Hydroxystearic Acid?

Hydroxystearic acid is a long-chain saturated fatty acid with a hydroxy group, often positioned at carbon 12, derived primarily from castor oil via hydrogenation of ricinoleic acid. It falls into the category of mild surfactants and emulsifiers in cosmetic formulations. This ingredient functions by lowering the surface tension at the interface of oil and water, promoting the creation of micelles that encapsulate dirt and oils for easy removal during cleansing. In emulsions, it stabilizes the blend of immiscible phases, resulting in smooth, consistent products like body washes, shampoos, creams, and micellar waters. Its fatty acid structure provides a non-drying profile, making it a common choice for everyday personal care items focused on gentle purification and texture enhancement.

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

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Surfactant
Lowers surface tension to enable cleansing, emulsifying, and foaming; central to shampoos, body washes, and many emulsions and micellar systems.
Cleansing agent
Removes dirt, oil, and impurities by lowering surface tension and forming micelles, enabling soils to be lifted and rinsed away from skin, hair, or teeth.
Emulsifying agent
Enables stable mixing of oil and water phases by forming an interfacial film, helping create lotions, creams, and cleansers with consistent texture.

Benefits

Aids in removing dirt and excess oils through micelle formation for thorough yet mild cleansing.

Stabilizes oil-water mixtures to produce even textures in lotions and creams.

Non-comedogenic nature supports clear pores without contributing to blockages.

Who It's For

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

Who May Benefit Who Should Avoid
Users of daily cleansers seeking effective impurity removal without stripping.
People with allergies to castor oil derivatives.
Individuals preferring emulsion-based products for smooth application.
Individuals sensitive to fatty acid surfactants.
Those with acne-prone skin benefiting from low pore-clogging potential.
Anyone advised by a dermatologist to limit emulsifiers.

Safety Notes

  • Considered low hazard for typical cosmetic concentrations.
  • Minimal irritation potential based on safety assessments.

Frequently Asked Questions about Hydroxystearic Acid

What does hydroxystearic acid do in skincare?

It cleanses by forming micelles to lift oils and dirt, and emulsifies for stable product textures.

Is hydroxystearic acid irritating?

It has low irritation potential, suitable for many skin types including sensitive.

Can it clog pores?

No, it carries a comedogenic rating of 0, indicating low risk of pore blockage.