Formulating with film-formers to reduce TEWL

Maintaining optimal skin hydration is a primary objective in cosmetic formulation and is fundamental to both skin health and product performance. The skin naturally loses moisture through a continuous process known as transepidermal water loss, or TEWL. While this physiological function is essential for thermoregulation and barrier homeostasis, excessive TEWL is associated with dryness, irritation, barrier impairment and accelerated visible ageing. As a result, reducing TEWL has become a central focus in modern skincare science, particularly in products designed to support barrier repair, protect sensitive skin or provide long-lasting moisturisation.

Film-formers play a crucial role in achieving this goal. These ingredients form a protective, flexible and often invisible layer on the skin that slows the evaporation of water without impeding skin respiration. Unlike fully occlusive agents, film-formers provide a balanced approach to moisture retention, supporting the skin’s natural barrier function while maintaining a comfortable and elegant sensory profile. Their versatility allows them to be used across a wide range of formulation types including moisturisers, serums, sunscreens, cleansers and specialised barrier-repair treatments.

This document explores the science behind TEWL, the different classes of film-forming materials, the strategies used to integrate them effectively and the formulation challenges that must be considered. It also examines compatibility, regulatory perspectives, testing methods and specific ingredient examples that demonstrate high performance in both functional and sensory terms.

By understanding the mechanisms, material choices and formulation approaches associated with film-formers, cosmetic chemists can create more effective, evidence-based skincare products that support lasting hydration, improved barrier integrity and enhanced user experience.

Download this informative document now and find the best film-formers for your products today!