Le Soins de la Peau de L’Hiver
Today, I’m going to discuss our skin and how it’s important to care for it when it’s colder outside. I am planning on writing more about biochemistry and cosmetics (skin & hair care) this year, since that is what I love/do, so I really hope y’all enjoy it!
When most people think of important organs, they’ll name nearly every internal system and completely neglect the largest on. Our skin. The skin is our body’s first line of defense. So even though several people think of it as superficial, it plays a huge role in our immune system. From protecting us from microbe-containing debris, regulating our temperature, or helping us absorb enough sunlight to create vitamin D, the skin is quite remarkable! But what exactly is skin?
Our skin is comprised of 3 different layers: the epidermis, dermis, & hypodermis. I won’t go too in depth with the details, but each one of layers also contains other layers. Think of it like an onion.
Epidermis: the outermost layer of our skin & it is mainly comprised of keratinocytes (cells that produce a protein called keratin) + lipids (fats). Keratin helps strengthen our skin + it is resistant to environmental toxins & physical stress. It’s also found in our hair!
There are 5 layers that make up the epidermis (in order from top to bottom): stratum corneum, stratum lucidum (only on our palms & soles of feet), stratum granulosum, stratum spinosum, & the stratum basale (contains melanocytes = cells that produce melanin)
The epidermis also contains dendritic cells (islets of Langerhans) which originate in our bone marrow (= immune properties). These dendrites act as ninjas, if you will, to fight off any foes (antibodies) from harming us.
Lastly, skin begins being synthesized in the stratum basale and moves upward, so once the cells reach the epidermis, they begin to shed. This process occurs every 26-42 days (it’s known as desquamation). Disturbances in desquamation can lead to skin disorders like psoriasis.
Dermis: unlike the epidermis, this layer only contains 2 main parts: the papillary + reticular layers. The dermis’ main role is to connect the epidermis to the rest of the body.
Papillary layer: found in palms and soles
Reticular: makes up 80% of the dermis & it is mainly dense, irregular connective tissue
The dermis also has an extracellular matrix which is mainly comprised of: collagen (I will write a post about collagen supplements soon), elastin, glycosaminoglycans = GAGs (I’m sure you’re heard of hyaluronic acid, right?), & proteoglycans
Hypodermis: the largest/thickest layer of skin that contains adipose/fat cells, which aid in anchoring the skin (so basically lots of veins & arteries are involved). This layer also contains cells that are responsible for converting UV light to vitamin D!
Whew! As you can tell, there is A LOT going on in the skin. I didn’t even touch on what all the layers in the epidermis are responsible for. So, hopefully reading this will encourage you to better care for your skin or at least appreciate its function a little more. If y’all would want me to go more in depth about any of these layers, please let me know, otherwise, the best summarization I’ve found is by Crashcourse. It doesn’t get too technical, so almost anyone can watch it and learn a thing or two.
Now that you know a bit of the basic anatomy of skin, I can go on to describing how our skin is affected when it’s winter. Xeroderma is just a fancy term for dry skin & if you already suffer from xerosis, then you become even more susceptible when the weather is colder. As you’ve probably heard, our bodies are mostly comprised of water and our skin is around 64% water. This is why staying hydrated is important to skin health (I drink waaaay too much water). But as we age and when environmental conditions change, the amount of water that evaporates from our skin increases. This is due to several factors that I won’t discuss, because I’m trying to keep this as simple as possible. But just like water, the lipid content in our skin changes as well. I will have to do a completely different post about skin lipids, because I would really like to go in-depth in that subject, but if you want to do some research for yourself, I will provide some data from one of my fave dermatology books. Remember the layers of the epidermis I mentioned above? Well the outermost layer, the SC, is comprised of a 20% lipid volume. That lipid volume is made up of 3 main lipids: ceramides (50%), fatty acids (10-20%), and cholesterol (25%). Yes, cholesterol is needed in your body!
With all that said, let’s discuss products and the main ingredients you should look out for (good and bad), when establishing your skincare routine. As I write this, I am very aware of all the different website (*cough cough* Paula’s Choice *cough cough*) that have already written about this topic, but there are a few people who have been asking me to do a post on this, so I am trying my hardest to give the best advice on this little section. Since, at this moment, I make my own skincare products, I will just link products that I would either use or contain similar ingredients to mine.
Avoid surfactants (aka surface-active agents)! Surfactants are comprised of 2 parts, a water soluble “head” and a fat soluble “tail.” This structure allows for them to strip the lipids from your skin and then be able to wash away with water. See, chemistry is simple! The only problem is, if you’re already dealing with xerosis, you want to keep in as much lipids as you can, so there are other types of cleansers for that. The pH of a product is also very crucial to this (yes, this will be another post).
Examples of surfactants: Sodium lauryl sulfate, ammonium laureth sulfate, disodium lauryl sulfosuccinate, cocamphocarboxyglycinate, cocoamidopropyl betaine, & α-Olefin sulfonate
Avoid alcohols!!! Till this day, I do not understand why alcohols are still used in toners. Even people, like me, who have oily skin should not use them. They might keep your skin dry for a little while, but then Le Châtelier’s Principle occurs and BAM! You can fry an egg on your face.
Moisturizers + Facial Oils
Try to avoid anything with petrolatum + mineral oil (not just because of the whole fossil fuels thing), but because this ingredient just sits atop your skin and does not penetrate your epidermis to get to the root of your dry skin issue. Also, you don’t want to shine like the top of the Chrysler Building. Try to look for products that contain jojoba oil! Jojoba oil is actually a wax ester (another type of fat), but it is able to penetrate the skin and actually make a difference in how your skin looks. Also look for products with ceramides.
Examples of good lipids: jojoba oil, ceramides, meadowfoam seed oil, baobab oil, rose-hip oil, red raspberry seed oil, sea buckthorn berry oil, argan oil, sweet almond oil, etc.
So what is the takeaway from all of this? In the winter, you should moisturize! BUT just make sure the ingredients in your moisturizer are not just sitting atop your skin. It is important to keep water in (which is why petrolatum is found in many dry skin formulations), but you also have to try to replenish the fatty acid & ceramide content in your skin.
Thank you for reading,
bisous bisous ♥