Hyaluronic Acid is formed by skin cells and is part of the connective tissue of the skin. One of its key functions is to retain moisture, and it has the ability to bind in between 1,000 and 10,000 times its own weight in water (i.e. one gram binds between one and ten liters). As we age, the skin's natural ability to produce Hyaluronic Acid depletes and wrinkles start to form and deepen.

Urea (also known as Carbamide) is produced naturally by the skin and is part of the essential Natural Moisturizing Factor (NMF) which regulates skin’s moisture content. Urea is hygroscopic, which means it is able to bind moisture into the outermost layer of skin. It is also keratolytic, meaning helps the skin to get rid of dead skin cells dead skin cells, to make it smooth again, and has anti-itch and anti-microbial properties. As a result, it improves natural exfoliation and soothes and smoothes the skin’s surface. As a substance produced naturally by the skin, Urea is well-tolerated even by dry and sensitive skin. Because all of these effects and very good study data, Urea is the gold standard in treating of dry skin.*

^{* Reference: Augustin M et al., diagnosis and treatment of xerosis cutis – a position paper, JDDG 2019, DOI: 10.1111/ddg.13906}

Ceramides are important lipids in the hydrolipid film (which protects the external layers of skin). Produced naturally in healthy skin, they strengthen the skin barrier, helping to prevent moisture loss due to evaporation and keeping out irritants that can cause inflammation and itching. When skin’s Ceramide levels fall the skin barrier is impaired. Skin can start to lose water and become dry and irritated.

Eucerin uses synthetic Ceramides that are biologically-identical and that enhance skin’s natural barrier – locking in moisture and preventing dryness and irritation.