Why is moisturising essential?
Because moisturisation increases water content, making it imperative for all skins types, even the oiliest.
Water and skin health
Skin is a protective barrier against water loss and harmful pathogens, through a film called the acid mantle.
The acid mantle is a mixture of our natural skin oils, sweat and natural moisturising factors (NMF; think of it as skin's natural humectants) in water. Thus, water is crucial in maintaining the strength of the barrier to
- keep unwanted microbes out by maintaining a slightly acidic pH of 4.5-5.5
- minimise water loss/dryness
- allow all skin functions to perform optimally including repair and shedding/renewal (desquamation)
Superficially, a lack of water translates to fine crepey lines, peeling skin, rough texture and dull or lacklustre skin tone . Not pretty.
How moisturisation is achieved
Since water is so important, it makes sense to retain as much of it as possible. This is where moisturisers come in. They contain ingredients that increase/maintain our skin's water content.
Moisturisation is achieved in 2 ways
- Directly - increase water content of skin through humectants
- Indirectly - decrease water evaporation through oils/emollients
Effective, long-lasting hydration requires both modes of action. This is why oils alone cannot actually moisturise - they do not actively increase skin's water content!
What are the best humectants and emollients to use in a moisturiser? That's coming up next, so check back soon!