Oils such as mango, avocado and argan oil are full of long chain fatty acids that moisturise and lock water into the skin. You can tell if an oil has long chain fatty acids if it is solid just below room temperature (21 degrees).
Hyaluronic Acid/Urea/Glycerine/Polyglutamic Acid
These are all humectants meaning they draw moisture to the skin and hold it there. If you’re using powerful humectants such as Hyaluronic acid that you mist your skin before applying - otherwise there is a danger that the acid will leech water from your skin (rather than the air) leaving you looking even more desiccated.
Aloe Vera
Aloe vera is a succulent plant that in the wild is designed to bind water in its leaves. It soaks straight into parched skin and holds water there.
Colloidal Oat
Finely ground oat powder has been used for centuries to soothe dry and itchy skin. Its mix of fats, proteins, vitamins, minerals, and other nutrients make dry skin feel soft and hydrated all day long.
Lactic Acid
When you have dry skin, it is usually also flakey. This is because the skin needs moisture in order to replenish (desquamate) itself. Lactic acid is one of the milder AHAs. It helps gently remove the top layer of dry skin allowing moisture to get in and help your face look lovely and fresh.