Beneath the Surface
It truly amazes me the wonders going on between the layers of our skin, just beyond our sight. Oh the infinite wisdom of our Creator!
These last few weeks between enjoying family coming to stay with us, I've been delving more into the structure of skin. As a quick anatomy refresher our skin has three layers: the epidermis, dermis, and hypodermis. Within those basic layers, each layers has its own complex set if you will. The epidermis (the outermost layer) has four layers, with an added fifth in places where skin is thicker like the palms of our hands and feet.
I've picked one of these epidermal layers and dug in a bit deeper. The top layer of the epidermis is the stratum corneum. It is the layer of skin we actually see. It looks similar to a basket weave, or another often used comparison is the bricks and mortar analogy. As cells (keratoinocytes) are formed in the bottom layer of the epidermis, the stratum basale, they travel upward finally reaching the outermost layer. The process I just described to you is called keratinisation. At this point we now have dead skin cells, which are sloughed off or exfoliated. The fancy word for this is desquamation. When cells are born in the basale layer they are living, but when they come to the surface they are exposed to air, no longer alive. This whole journey of the skin cells takes about 28 days, but lengthens as we age. After age 50, it takes more like 37 days for cells to rejuvenate. This time span is important for us to be aware of especially when thinking about exfoliation and skin sensitivity. Are you scrubbing your skin too much or too harshly? Are you not exfoliating at all? There are scrubs out there that remove more layers of dead skin cells than are necessary. This can also lead to increased oil production, which is what you don't want if you tend to have oily skin. Exfoliating is a very good thing. Who doesn't want smooth, glowing skin? The question is how often should I exfoliate? The There are different types of exfoliation too. Mechanical (think jojoba beads, rose hip powder, ground oats etc), chemical (glycolic acids like salicylic acid) and enzyme (often from fruit). This isn't meant to be a post on exfoliation, but while I'm on the topic, how often is appropriate to exfoliate. The answer totally depends on the method being used. Most mechanical forms can be used one to two times a week. My currant favorite is using rose hip powder or apple fiber powder. The "grain" is tiny and when mixed with water or even an oil cleanser it works so gently and so thoroughly. Chemical and enzyme exfoliants, or peels rather, will say on the box or label how often they should be used.
Okay, back on course :) The corneum has some big responsibilities. It's top priorities also includes protecting itself from foreign matters entering the skin and preventing major moisture loss (aka dehydration). This is where that bricks and mortar picture I mentioned earlier comes into play. It looks like this: the bricks are the dead skin cells (now called corneocytes) and the mortar filling in the cracks is this lipid or oil rich matrix. These lipids act as a barrier trapping water in the layers beneath, preventing excessive water loss. Maybe you've heard of Natural Moisturizing Factor? The brand, The Ordinary, has a product designated to it https://theordinary.com/product/rdn-natural-moisturizing-factors-ha-30ml?redir=1. Basically, 20%-30% of the skin cells we see on the surface of our skin contain NMF. They are water-soluble compounds that are found only in the stratum corneum which help your skin stay hydrated. In case you care to know, NMF is a combination of about 40% free amino acids, 12% PCA, 12% lactic acid, 7% urea, and the other 30% being a blend of various components. Harsh detergants and harsh climates like dry cold winters and very hot sun and wind can decrease the Natural Moisturing Factor in our skin.
Understanding what our skin is composed of just a bit more, can also help us understand what our skin might need, products, and their penetration. This is really just the tip of the ice berg, but I hope I've been able to paint even a small picture for you of the life happening right inside our own skin.
Until next time . . .