The human skin has a thin protective layer of dead cells (Stratum Corneum), which naturally shed over time in a process called desquamation. Skin cells are produced at the lower layers of the epidermis and travel to the visible surface of the skin (takes between 14 – 28 days), where they die and shed from the skin, to be replaced by newer cells keeping the skin tone even and healthy. Most of the visible skin is composed of dead cells, which are tough and help protect you.
However, many things can interfere with and slow down the desquamation process, such as aging (can start as early as 25), environmental factors (exposure to sunlight), hormonal fluctuations, lack of sleep, poor diet, deficiencies in various vitamins, pollution and environmental changes. With all of these influences affecting the desquamation process, it is apparent why exfoliation is so important to the skin. Removing this build-up of dead, damaged cells stimulates the regeneration of new cells, improving the skin’s appearance, feel and texture. Not exfoliating can lead to breakouts, clogged pores, rough patches, wrinkles, and dull/uneven skin.
There are 2 main categories of exfoliation: Physical/Mechanical and Chemical.
Physical/Mechanical Exfoliation
Physical/mechanical exfoliation employs the use of either a tool (e.g. Brush or Sponge) or ingredients (e.g. Polystyrene Beads, Sugar/Salt Grains, Ground Coffee, Crushed Apricot Kernels, Rice Bran, Oatmeal) that physically buff away dead cells from the surface of the skin mechanically. Physical exfoliation has a reputation for being harsh as many scrubs available on the market can be too coarse to be used on people’s faces, e.g. Apricot Scrub. Also people use physical exfoliants too frequently, scrub too hard and feel like it is not working if their skin doesn’t feel “squeaky” clean afterwards. This is very wrong! Over exfoliating can result in skin irritation and will ultimately make your skin worse, reducing the ability of the Stratum Corneum (outer layer of the skin) to act as a barrier against microbes and prevent moisture loss. The skin on the face is thin and delicate so gentle exfoliation is advised (do NOT over apply pressure) and should be limited to once or twice a week. Remember the goal of exfoliation is simply to remove the old dead layer of the skin from the surface, not to rip perfectly healthy new skin off.
Chemical Exfoliation
Chemical exfoliation employs a variety of means to achieve skin renewal such as Alpha Hydroxy Acids – AHAs (like Lactic Acid, Glycolic Acid, Mandelic Acid), Beta Hydroxy Acids – BHAs (Salicylic Acid), Retinol (i.e. Vitamin A) and protein-digesting Enzymes (like Papain, Bromelain and Actinidin). It’s not entirely clear how Hydroxy acids work to exfoliate the skin, it is likely to be a combination of increasing cell turnover at the epidermis and dissolving the “glue” (desmosomes) that holds skin cells together, so the dead cells simply slough off. As well as just removing dead skin cells, they also improve hyperpigmentation and reduce the appearance of fine lines and wrinkles.
Choosing which chemical exfoliant to use can be quite tricky as there are different kinds of formulations (rinse off products, leave on products) and they come with different percentages. It is advised that you start with low percentages and slowly increase the concentration to avoid irritation. If your skin is really sensitive, you can start with a low percentage hydroxyl acid leave-on product and mix it with a moisturizer until your skin gets used to it.
Here is a simple guide:
Best for dry and sun-damaged skin: Glycolic Acid
Best for oily and acne-prone skin: Salicylic Acid
Best for sensitive skin: Lactic Acid (not as effective at Glycolic acid as it has larger molecules which don’t penetrate the skin so well)
Best for aging skin: Retinol (It is not exactly classified as an exfoliant but it increases cell turnover which helps dead skin cells detach. It can be mixed with AHAs)
Remember that chemical exfoliants increase the photosensitivity of the skin so it extremely important to use a very good sunscreen (broad spectrum <SPF 30) daily.
So, Which Is Better, Chemical Or Physical Exfoliation?
Both types of exfoliation have their benefits, and different types of physical or chemical exfoliation have their advantages and disadvantages too. To be honest, there is no hard and fast rule about which type of exfoliation to go for as all skin types can benefit from both physical and chemical exfoliants. In general, people tend to see greater effects using chemical exfoliation as they work on the deeper layers of the skin.
Here are some advantages and disadvantages:
Physical Exfoliation
|
Advantages
|
Disadvantages |
| Immediate results | Only works on uppermost skin layers |
| Lower chance of an unexpected allergic or irritant reaction |
Can be harsh and abrasive, easy to scrub too hard leading to over-exfoliated skin |
Chemical Exfoliation
| Advantages | Disadvantages |
| More precise and works more evenly than physical exfoliation | Slower to work |
| Ingredients often have secondary advantages (e.g. Glycolic acid boots collagen production and hydrates skin) | Higher chance of unexpected allergic or irritant reactions |
| Works deeper and more effectively than physical exfoliation | Can cause photosensitivity |
In summary, if you want smoother, brighter and younger looking skin, exfoliation is the way to go. Start exfoliating once a week and increase frequency if it looks like it is working well. For leave-on products, do a patch test before incorporating them into your routine, especially if you have sensitive skin. Watch out for over-exfoliation, if your skin becomes red and tight you are most likely over-exfoliating, take a break for a few days to let you skin recover then start again slowly.
If you are still confused about what type of exfoliation to choose, please feel free to send me an email: Hilary@hilaryrodriguez.com
Photo Credit: Botanik Boutique
