5. Protects the barrier function of the skin
One of the major jobs of the skin is to protect us (to a point) from harmful toxins, free radicals and the dangerous UV rays of the sun. It does this by maintaining a lipid barrier in the upper layer of skin called the stratum corneum.
The stratum corneum is made up of ultra-tough skin cells called corneocytes, but these skin cells would be nothing without the lipids (fats) that hold them together. If the corneocytes are the bricks of the stratum corneum, the lipids are the cement.
These lipids are made up of ceramides and fatty acids, and as well as protecting us from the environment, they form a waterproof barrier to prevent moisture from escaping, drying the skin out.
But again, harsh environmental conditions can damage this barrier. Over-washing, long, hot baths, allergens, irritants, sunburn and exposure to harsh chemicals from soaps and perhaps our working environment can all also compromise the barrier function of the skin.
Using a moisturiser, especially one that contains ceramides, helps to maintain the lipids in the skin, helping to better our resilience against UV radiation and toxins, leading to overall happier skin.