C18-38 Alkyl Hydroxystearoyl Stearate

C18-38 Alkyl Hydroxystearoyl Stearate is a synthetic ester derived from stearic acid and fatty alcohols. It functions primarily as an emollient and emulsion stabiliser in skincare formulations, helping oil and water-based ingredients blend smoothly and remain stable over time.This ingredient is used sparingly in skincare products (found in roughly 0.1% of formulations) and serves a technical rather than a standalone therapeutic role. Its presence typically indicates a carefully formulated product where texture, spreadability and long-term stability have been considered.

As an ester, this ingredient works by depositing a thin, occlusive layer on the skin's surface. This helps reduce transepidermal water loss and creates a smoother appearance by filling micro-gaps in the skin's texture.In formulations, it acts as an emulsion stabiliser by positioning itself at the oil–water interface, allowing the product to maintain a consistent texture and preventing ingredients from separating over time.

This ingredient is a formulation component rather than a standalone active, so its benefits are best experienced as part of a complete product. Use according to the product instructions. Its effects are cumulative with regular use, particularly for improving skin texture over several weeks. It works well in moisturisers, serums and lightweight creams where a refined texture is desired.

Generally well-tolerated and rarely associated with irritation or sensitisation. It is not known to cause photosensitivity or interact significantly with other skincare ingredients.