Lack of hydration and lack of nutrition are two different but closely related mechanisms. If hydrating your skin is essential, only good nutrition will maintain hydration.
Explanations.
Lack of water or lipids?
Dry skin lacks lipids, dehydrated skin lacks water.
By way of illustration, the first “hungry”, the second “thirsty”.
Dehydration is primarily caused by a lack of water intake, but also by temperature variations and pollution.
Dry skin results from insufficient secretion of lipids, in the form of sebum. On a physiological level, the skin is naturally nourished by this sebum which, when produced in too large quantities, is responsible for oily skin. But when it is missing, the hydrolipidic protective film is insufficient to ensure its barrier function: Subjected to external aggression, the skin of the face dries out very quickly.
How to differentiate them?
Lack of hydration and lack of nutrition manifest differently.
Dehydrated skin is essentially characterized by a feeling of discomfort, with tightness and tingling. But no drought is visible.
Dry skin feels rough to the touch, with signs of dryness and flaking. The pulling is continuous. This is the “crocodile skin” effect.
What contributions?
To have well-hydrated skin, it is essential to have sufficient daily water intake: to drink, and also to eat fruits and vegetables. But it is also essential to provide moisturizing active ingredients when applied to the skin. These moisturizing treatments will contain active ingredients of natural origin such as Aloe Vera or hyaluronic acid for example.
By applying treatments containing fatty active ingredients such as vegetable oils, we protect the skin from dehydration: the skin cells remain well stuck to each other, the hydrolipidic protective film strengthens by constituting a barrier which will reduce dehydration avoiding natural evaporation.
An order to respect?
So nutrition and hydration are complementary, but should you respect an order of application in your routine?
In theory: first hydrate, then nourish to lock in hydration. So so-called rich treatments (creams) must be applied after moisturizing treatments (oils, oily serums).
In practice, opinions differ and lead to one conclusion: it is up to each person to evaluate the strategy that will suit them best!
Synthetic
It is essential to hydrate and nourish your skin. Skin hydration requires sufficient water intake through drinks and food on the one hand, and cosmetic treatments containing moisturizing active ingredients on the other. Nutrition requires care rich in vegetable oils, which will create a barrier preventing water loss. Only oily skin will have reduced nutritional needs.