Skin 101: Learn Basic Anatomy for Skincare!
All doctors agree: the skin is the largest and most important organ. As dermatologists, sometimes we see advice on Tik Tok that promotes certain products that are not good or even (uh oh) harmful to your skin! We want to educate you on the science of the skin - so you can understand why certain products / procedures work better than others, and you can decide what's best for your unique skin!
We’ll try to make this less as EXCITING as possible (well, as much as learning about the skin can be exciting). We’ll teach you what is important to know about the skin: no more, no less. Let’s go!
Skin Basics
For Skin 101 purposes, we'll make this easy. For most skin conditions, we're dealing with two layers of the skin: the epidermis (what you see) and the dermis (right below). Easy, right?! Topical medication is meant for conditions in the epidermis/upper dermis, while we usually need pills or injections to reach deep down into the dermis. It's too deep for a cream to reach!
For Skin 101, we will concentrate on three structures within the skin:
Stratum Corneum - The famous “Skin Barrier.” This layer of the skin gets lots of press. It’s important for moisturizers!
Melanocytes - Cells that make pigment. Located at the very bottom of the epidermis. These are important for dark spots or light spots!
Dermis - Thick layer full of strong collagen. ~1.5mm thick on the face. It’s important for texture, pores, wrinkles, scars, etc. It’s difficult for topicals to reach this layer because it’s so deep. That’s why topical treatments for wrinkles and scars usually don’t work well.
If You’re Concerned About Moisture…
…then you should focus on your stratum corneum! This layer is actually “dead” and acts as a shield to protect us from sun, dehydration, bacteria, and well, everything! Our stratum corneum looks like a brick wall:
Bricks = dead skin cells
Mortar = ceramides, cholesterol, fatty acids
You may have heard of ceramides as a common ingredient in moisturizer. This is to reinforce the layers between the dead skin cells. We’ll cover this more in Moisturizer 101!
It’s very important to keep our stratum corneum happy and functioning so it can fully protect us. If it's too thin or too damaged to function, it can't keep irritants out or water in. When this happens, our skin becomes inflamed, red, itchy, flakey, and burning. It’s important to recognize a damaged skin barrier (AKA damaged stratum corneum). When damaged, the skin needs some “time off” in order to heal (like you need time for a broken bone to heal!). If you have a damaged skin barrier, use only gentle moisturizer, cleanser, and sunscreen for 2 full weeks (for the stratum corneum for fully restore). When our stratum corneum is healthy and hydrated, our skin cells can keep water in and the bad guys out!
Did you know: When you are dusting your home, you are dusting up dead skin cells that you've flaked off!
If You’re Concerned About Pigment…
…then you should focus on your melanocytes! These cells make melanin to give us our skin tone. Melanocyte cells live on the bottom of the epidermis. They are hard at work producing pigment, packing it, and distributing it to the whole epidermis to protect you from UV damage. They're shielding your whole body from the sun!
Melanocyte cells are very sensitive. They can stop working if it’s too hot, too cold, or if there’s any trauma to the skin.
Let’s focus on the melanocyte cell itself. Because melanocytes are relatively superficial within the skin, topicals can work beautifully to alter pigment production. For example, let’s say you have a dark spot that you’d like to lighten. Within the melanocyte, there are 4 steps to make pigment. We can stop each of these 4 steps to reduce pigment production! You’ll likely recognize some of these ingredients, as they are very popular in skincare. Combining ingredients from different steps have the best chance of working.
Learn more about Retinol, Vitamin C, or Niacinamide here!
If You’re Concerned About Wrinkles or Scars…
…then you should focus on your dermis! Beneath the epidermis, we have the dermis. This is a more durable layer, filled with collagen and elastin to provide structure and elasticity to the skin. The dermis varies in thickness based on the part of the body: it is thinnest on the eyelids (just 0.5 mm) and thickest on the back (up to 1 cm!). Our dermis gets thinner as we age, hence the formation of wrinkles. For Skin 101 purposes, the dermis is under the epidermis, thicker, and gives us support! There's many structures in the dermis, but for our purposes, we will focus on three:
Hair Follicles - We are COVERED in hair, except for the palms, soles, and if you got a Braz... we'll leave that for Skin 102.
Oil Glands - AKA "sebaceous glands". Important in acne. Each oil gland dumps directly into a hair follicle so oil can disperse onto the skin.
Sweat Glands - AKA "eccrine glands" produce sweat and assist us in temperature regulation.
Note: When Eminem's "Palms are sweaty, knees weak, arms are heavy," he is referring to the eccrine glands of his palmar surfaces, which have the highest density of sweat glands in the entire body.
Thanks for the fun fact, Marshall!
Congratulations, You Passed Skin 101!
Now you are a Board Certified Dermatologist, congrats! Take a break and when you're ready, you can continue on to Scalp 101!