New Jersey Esthetics Practice Exam 2025 – Complete Test Prep

The main component of the epidermis that helps retain moisture is keratin. Keratin is a fibrous protein that forms a protective layer on the skin. It is a crucial part of the skin's barrier function, helping to prevent water loss and maintain hydration. The structure of keratin provides strength and resilience, allowing the skin to function effectively as a barrier against external elements.

While sebum, collagen, and elastin are important to skin health and structure, they do not play the primary role in moisture retention within the epidermis. Sebum, produced by sebaceous glands, contributes to skin lubrication and can help create a barrier that prevents moisture loss, but it is not a component of the epidermis itself. Collagen is primarily found in the dermis, providing structural support and elasticity, and elastin also resides in the dermis, allowing the skin to stretch and rebound. Hence, keratin stands out as the essential component in the epidermis responsible for retaining moisture.