Welcome to a new installment in what has become a mini-series about exfoliation. I wrote about this a few years ago and have updated the information, so let’s get started.

Today, we're going to look at chemical exfoliants - what they are and how they work, and we're going to learn how to do DIY chemical exfoliating. If that sounds a little scary, stick with me and I predict you’ll be all smiles in a mere moment.

You might be wondering why we're looking at delicious edibles while talking about chemical exfoliants. The reason is quite simple, as you shall shortly discover.

But before we get busy exfoliating, let's take a super brief historical peek at chemical exfoliation.

It's as Old as The Hills

Chemical exfoliation (also called peeling) is actually not at all new. The Egyptians have references to it as early as 1550 BC. I've tried to discover exactly how it was used around 1550 BC, but information is exceedingly scarce.

Fast forward several hundred years:

The use of chemical substances to improve various skin conditions surfaced (again) in the 1800's where Austrian physician and dermatologist Ferdinande Hebra entered the scene. Hebra wrote the groundbreaking Atlas of Skin Diseases and helped set the stage for many modern dermatological practices. He used chemical peeling agents such as phenol, croton oil and nitric acid in various combinations. Among (many) other things, his medicated soaps were developed and sold to 'treat freckles and wash away tan'.

How Chemical Exfoliants Work

Chemical exfoliants work by dissolving the protein binder (or 'glue') of skin cells. This allows the cells to be shed from the skin.

Using a chemical exfoliant might sound like the harshest thing you could possibly put on your skin, but chemical exfoliants can be quite effective without being harsh.

Acids For Skin

You've probably heard of alpha hydroxy acids (AHA's). Some of the most typical chemical exfoliants are AHA's. A quick look around your kitchen will likely reveal a number of AHA-rich ingredients because they are naturally present in many fruits and foods. Apples, lemons, limes and even sugar cane have a natural content of AHA’s.

While they have many natural sources, AHA's can also be synthetically made.

Here's a breakdown of some of the most common alpha hydroxy acids:

Glycolic Acid

With excellent skin penetrability, glycolic acid is not only ideal for 'tickling' the cells and making them want to grow, it's also widely used in skincare. Natural sources include fruits such as pineapple, sugar cane, sugar beets, and (unripe) grapes.

For cosmetic use, glycolic acid is created to be nature identical (read: a chemical 'copy' is created in a lab environment).

Glycolic acid has a small molecule size and it is the concentration of the acid and the pH that makes for its strong effect. A higher concentration will effectively remove a layer of skin. Depending on the pH level, glycolic acid can be a serious skin irritant. Dosed correctly, it's an effective exfoliant.

There are different production methods for this ingredient. Some result in unwanted extra components (such as formaldehyde). For cosmetics use, the purer the final product, the better.

Mandelic Acid

From the German word Mandel (which means almond), mandelic acid is indeed sourced from almonds. It is often combined with other AHA's for chemical exfoliation/peels.

Citric Acid

You've probably already guessed the source of this widely used AHA. Aside from functioning as a pH regulator in many cosmetics formulations, citric acid is also used in combination with other AHA's for various skin treatments.

Lactic Acid

There are many stories of Cleopatra bathing in milk to keep her skin beautiful. They could very well be true, because milk contains lactic acid – an effective chemical exfoliant. But Cleopatra probably wanted maximum effect from her milk bath, so her preference may well have been the most lactic-acid-rich milk of all – donkey's milk.

Because lactic acid is a natural part of the human body, it isn't likely to cause allergic reactions. Using Lactic acid for chemical exfoliation helps hydrate the skin, helps stop bacteria production, and even slows down pigment accumulation.

Here's a list of the benefits of using lactic acid to exfoliate:

Good for fighting hyperpigmentation
Helps reduce fine lines and wrinkles
Helps unclog pores
Helps prevent blocked follicles
Helps prevent age spots
Helps for sun damage

For Once, More is Better

Percentages matter: a study showed that applying 12% lactic acid twice daily over a period of 12 weeks made a measurable difference in thickness of the skin. Both epidermis and dermis showed improvement. In the same study, another group used only 5% lactic acid and had less positive results. In this case, more was better. (links below)

The best lactic acid sources:

buttermilk
sour cream
yoghurt

DIY Chemical Exfoliating

Natural yoghurt is an effective, inexpensive and incredibly easy face treatment. It is mild enough to be used daily, yet effective enough to where you will see a noticeable difference with daily use.

Simply apply natural yoghurt to cleansed skin in a thick layer (or layer it up with many thin applications) and let it sit for as little or long as you please.

For better adhesiveness and staying power, you could add a small amount of kaolin clay, but if the yoghurt is thick enough, then feel free to use it straight up.

It’s as easy as applying, allowing to sit for as long as you please, then removing

To remove:

Gently ’scrape’ off the yoghurt with a spoon
Rinse face
Pat dry
Finish with face mist (hydrosol) and a few drops of your favorite face oil or moisturizer

On some days, I'll only have 5 minutes to do a yoghurt mask, but even 5 minutes is better than no minutes. And this treatment is so easy, quick, cheap, and effective, how can you not want to do it every day?

Enjoy!