— § 01
What ceramides actually are.
Ceramides are sphingolipid molecules that, with cholesterol and free fatty acids, build the lamellar matrix of the stratum corneum — the structural mortar between corneocytes. They are the skin's primary water-retention infrastructure. When that matrix breaks down (age, harsh cleansers, retinoid onboarding, eczema, winter air), transepidermal water loss rises and almost every active becomes harsher than it should be.
Topical ceramides — particularly when delivered with cholesterol and fatty acids in physiologic ratios — measurably restore that matrix. This is one of the rare skincare claims supported by both bioengineering data and decades of clinical use in atopic dermatitis. It is also one of the most undersold ingredients on the market.