Ectoine is a natural substance with which the Halorhodospira halochloris bacteria protect their cells from drying out. It is an extremely halophilic bacterium (meaning that it requires a salt-rich environment for its growth and survival), which is isolated from the hypersaline Wadi el Natrun lakes, located in the desert of the northwestern Nile Delta in Egypt. So it is a skin protection coming from the desert basically.
What the ectoine actually does is that it forms a special water system in the skin. In this way the proteins of the skin are stabilised with water and concentrations of salt. Ectoine assures that the water pocket of these proteins lasts longer which makes them more resistant to UV radiation as a natural protection.
Ectoine is used in skin protection cosmetics like FRESH moisturiser for men, Hydro Serums, Anti-wrinkle Serums, Eye Serums and day creams.