Our skin’s epidermis acts as its first line of defense, and its outermost layer, the Stratum Corneum, contributes the most protection. NMF (Natural Moisturizing Factor), whose main role is to maintain adequate skin hydration, is contained within these skin cells.
- maintains plasticity of the skin which protects it from damage
- allows hydrolytic enzymes to function in the process of natural skin cell shedding (desquamation)
- contributes to optimum stratum corneum barrier function.
The NMF is a blend of efficient humectants that attract and bind water from the atmosphere, drawing it into the corneocytes.
The lack of NMF manifests as areas of dry skin with scaling, flaking, or even fissuring and cracking. These conditions include Atopic Dermatitis, psoriasis, ichthyosis vulgaris, and xerosis.
What causes NMF loss?
Routine soap washing of the skin has been shown to remove the NMF from the superficial layers of the stratum corneum. In fact, the outermost layers typically show reduced NMF levels, largely due to bathing or exposure to UV light. Age is also a factor, since sebum and NMF production decreases as age increases.
So how much water does the skin actually absorb?
Actually, only one-thirds of the water contained in the Stratum Corneum is bound within the skin, with the remainder escaping. So does this mean that soaking in the bath doesn’t actually ‘hydrate’ your skin? Kinda. It is only the NMF-bound water that maintains skin elasticity.
How can we replenish NMFs?
We can replenish NMF through the external application of moisturizers that mimic the NMF function. Moisturizers are advised to be applied immediately after showering or bathing since water evaporates from your skin really quickly, leaving it dry. It helps keep some of that water on the skin, making it softer, pliable, and smoother. (This is where the different types of moisturizers come in. We’ll write a blog post on that soon!)
This is also why humectant ingredients (ingredients that attract water to skin) such as urea, lactic acid, and hyaluronic acid have recently sprung up in popularity in many cosmetic formulations, because it is one of the many components in the NMF blend!