What is exfoliation?
Every 1 to 3 months, a snake crawls out of it’s skin. In a process called shedding, the snake grows new skin under its old skin and leaves the old skin behind in one piece. Weird as it sounds, shedding isn’t unique to snakes. All animals shed their skin in one form or another, including us humans. In a process called desquamation, we lose about a million skin cells every single day.
Desquamation and exfoliation mean the same thing, but in popular lingo, the former tends to be reserved for the natural process that’s happening on an ongoing basis, while the latter usually refers to leveraging an external tool - mechanical or chemical - to nudge the natural process along more smoothly, and that’s the distinction I’m going to stick with in this post for clarity.
Here’s how it works. Our skin is made up of layers. There are three main layers: the epidermis, the dermis and the subcutis, and then there are sublayers. To understand the process of exfoliation, we need to concern ourselves with a slightly deeper understanding of the structure of the epidermis.
As shown in the figure, the epidermis is the top layer of the skin and consists of 5 sublayers. The deepest one is called the basal layer, or the stratum basale, and the outermost layer - the one that is externally visible - is called the corneal layer, or the stratum corneum. The cells in the basal layer are constantly dividing and producing new skin cells. As new cells are formed they are pushed up towards the stratum corneum in a process that typically takes around four weeks. The pace of this process however, tends to slow down as we get older and is also affected in people with skin conditions like psoriasis.
As skin cells are pushed up the layers, they become flatter and eventually lose their nuclei and die so the stratum corneum consists entirely of dead cells. Cells from the stratum corneum shed off constantly as enzymes present in the skin dissolve the “glue” - desmosomes - that holds them together. They are replaced by new cells that are pushed up from deeper layers. The normal process of desquamation is invisible as single corneocytes, i.e. dead skin cells , or very small aggregated units of them are shed off - we’re not snakes after all.
Healthy skin, where I define healthy skin as skin that’s able to properly maintain its barrier function of keeping hydration in and irritants and bacteria out, depends a great deal on the maintenance of a healthy stratum corneum. The health of the stratum corneum in turn depends on its proper continuous regeneration and the desquamation of devitalised cells.
What happens when the desquamation process goes wrong?
Over the years, everything in our body undergoes change, including the skin. One of these changes involves the progressive drying out of skin, which often also results in itching. This change can at least partly be attributed to the slowing down of the natural desquamation process, and is also experienced by people whose skin has prematurely aged for example, due to excessive sun exposure.
Other skin conditions, like psoriasis and ichthyosis, can also affect desquamation as can factors such as hormones, vitamin deficiencies, diet, environment, and even skincare. Impaired desquamation results in skin that is dull, as dead cells accumulate on the surface and scatter light instead of reflecting it. It also has a rough and uneven tone and texture. Impaired desquamation is also a key factor in the development of acne: since the “glue” between skin cells doesn’t dissolve properly, they shed off in larger aggregates that have a higher likelihood of clogging your pores.
What is exfoliation and how does it benefit the skin?
Exfoliation refers to the use of external tools and products to help remove dead cells from the skin’s surface. It benefits your skin by helping your skin’s natural desquamation process chug along more smoothly so skin conditions related to impaired desquamation, that we took a brief look at in the last section, don’t arise.
In my experience, while the amount required may vary from person to person and skin type to skin type, exfoliation is an essential skincare step for anyone over puberty. It’s also the only step that has an immediate positive impact on your skin, often resulting in brighter, softer skin with more even tone and texture, from the first use.
The benefits of exfoliation don’t end with this though. Here are some other benefits you can expect to experience with regular exfoliation:
Exfoliating your skin helps other products work better. Dead skin cells sitting on your skin’s surface form a barrier that stops skincare ingredients from being absorbed. Removing excess dead cells and clearing out your pores allows serums, moisturisers, and other skincare products to penetrate deeper and work better.
Better makeup application. Exfoliation removes dryness and flakes from the surface of the skin and evens out skin texture resulting in a smoother canvas for applying makeup.
Depending on the exfoliant used, it can even treat acne. When it comes to treating and preventing acne, exfoliants are not created equal. In this domain, chemical exfoliants are better and within the broader category of chemical exfoliants, salicylic acid reigns supreme. Salicylic acid, or BHA, has the distinction of being the only oil soluble hydroxy acid used in skincare. This allows it to penetrate your pores to loosen up existing clogs and keep new ones from forming. It is also antimicrobial and anti-inflammatory. These characteristics make it extremely beneficial for individuals with acne. You can read more about incorporating salicylic acid into your skincare routine, here.
Helps with pigmentation. While pigmentation is caused by excessive melanin production and is not necessarily related to desquamation, exfoliating can help with it by breaking up pigmented cells and sloughing them off. Combined with a topical agent such as vitamin C that targets melanocytes, the skin’s pigment factories, exfoliation can be especially powerful.
Helps fight off skin ageing. Chemical exfoliants help speed up the rate at which skin cells are renewed, a process that as we discussed earlier, slows down as we age. They also stimulate collagen production and help reduce the rate at which collagen is broken down in the skin. These properties make it ideal for individuals looking to fight off the signs of ageing such as fine lines and wrinkles.
However, before you incorporate exfoliation into your skincare routine, make sure that your skincare basics: cleanser, moisturiser and SPF are in order. SPF is especially important when you’re exfoliating since exfoliation can make your skin more sensitive to the sun resulting in an exacerbation of the conditions that you’re looking to treat.
If you’re not entirely sure of whether or not your basic skincare routine is in order, check out this post on how to build a skincare routine, or get in touch with us for a free skincare consultation. In subsequent sections I’ll cover the different types of exfoliants, and I’ll give you pointers on how to incorporate exfoliation into your skincare routine for maximum effectiveness.