Epidermis

What is it?

The epidermis is the skin’s outermost layer and serves as the body’s primary barrier against environmental threats, harmful microbes, and moisture loss. Though it's incredibly thin, it plays a crucial role in overall skin health, appearance, and function.

This layer is mainly composed of keratinocytes, which produce keratin—a protein that reinforces the skin and helps retain hydration. It also includes melanocytes, responsible for producing melanin and determining skin tone; Langerhans cells, which contribute to immune defense; and Merkel cells, involved in sensing touch. Together, these cells help the epidermis protect, repair, and regulate itself.

How does it work?

Since the epidermis lacks its own blood supply, it relies on the dermis beneath it to receive nutrients and oxygen. Its overall health depends on a well-functioning barrier often called the acid mantle—composed of sebum, sweat, and lipids. When this barrier is intact, it helps the skin retain moisture and block out irritants. If compromised, the skin can become dry, sensitive, inflamed, or more vulnerable to infection.

Most topical skincare products work on this outer layer. Ingredients like AHAs, retinoids, and niacinamide act on the epidermis to improve texture, stimulate cell turnover, and fade pigmentation. Moisturisers help replenish the lipids in the stratum corneum, strengthening the barrier and keeping skin hydrated and smooth.

The epidermis naturally renews itself about every 28 days, though this process slows with age, stress, or environmental damage. Gentle exfoliation and proper hydration support this renewal cycle and help maintain clear, resilient skin. Sunscreen remains essential, as UV rays cause damage starting at this level, contributing to early ageing and increasing the risk of skin cancer.

This layer is where effective skincare starts—and where even small improvements can lead to visible results.