Looking at the chemistry behind the term hydration it describes the arrangement of water molecules to create the formation of a protective hydration shell with the help of hydrogen bonds. This envelope offers protection and prevents damage to the skin from factors such as environmental stressors and noxious agents.
Moisture can leave the skin by a physical process known as evaporation which takes place at the surface of the skin. In layman terms this is known as sweating and is a process that is limited. The skin possesses a multitude of regulatory mechanisms to keep the upper layer, known as the stratum corneum, adequately moisturized.
Maintenance of the water content of skin
Furthermore, good skin care can significantly reduce the amount of water lost from the skin and thus increase the moisture content of the skin. The skin’s surface lipid layer plays a vital role in the hydration process.
Intercellular lipids (lipids located between cells) store moisture by using their hydrophobic properties to reduce the amount of water lost via evaporation.
Hydrating Skincare Products: Recommendations
Various active ingredients are capable of improving the skin’s moisture by strengthening the skin’s surface lipid layer. An example is almond oil, a product used in ancient Chinese, Ayurvedic and Greek medicine (2).
A randomized controlled and double-blind study showed that the application of lactic acid and refined almond oil, both with and without polidocanol (an antipruritic agent), led to a significant reduction in itchiness and an increase in the skin’s lipid content (3).
Aloe vera extract
Another class of ingredients shown to improve skin moisture and elasticity are aloe vera extracts. One particular study showed that a moisturizing cream containing aloe vera extracts, as well as wheat germ oil and other herbal ingredients, provided a measurable hydrating effect when participants applied the cream twice daily for three weeks (4).
Keys for skin hydration
Various topical preparations with a variety of active ingredients are available. These are important points to remember for achieving long-lasting hydration:
- Regular topical application of a moisturizing cream
- Adequate consumption of fluids (2-3 litres per day)
- Protecting the skin from drying out (avoiding air conditioning, excessive washing and sun exposure)