Chemical exfoliating 101

When I'm preparing my skincare posts, I want to provide an enjoyable read for both beginners and HC skincare enthusiasts. Some of these pieces of information seem so mundane and general knowledge to me I wonder if sharing them again is worth it? After having multiple chats with my friends, only a few had heard of chemical exfoliants. I think they're unsung heroes of skincare, especially where I live the importance of chemical exfoliating isn't loudly hyped up. Personally I love chemical exfoliants, I think every one should know how to use - or in some cases avoid them!  (PS. never put lemon on your face, they're just for decorative purposes)

Why should one exfoliate?

The uppermost layer of our skin consists of dead skin cells with a cell turnover of ~28 days, which slows down as we age. A packed layer of these dead skin cells can make our skin appear appear dull, uneven texture or congested. Most common form of acne is caused as a hair follicle gets clogged by excess dead skin cells and sebum. Exfoliating gets rid of the dead, old skin cells revealing younger, plumper skin underneath. It helps to brighten our skin, safely get rid of pigmentation or scaring over time, help with texture issues and even acne and blackheads. After exfoliation other skincare products will also penetrate better, making them more efficient.

Chemical exfoliation or scrubs

Scrubs are lotions, gels, etc. which contain small grains of salt, sugar, coffee, oats, powders and unfortunately in some cases microbeads, which pollute our environment. Scrubs can also be washing cloths, dry brushes and gloves, basically any mechanical/physical exfoliator. I find them especially beneficial for my body skin like elbows, knees, legs or anywhere I can use more abrasive exfoliating. The problem with facial scrubs is you can make micro cuts on your face, which can damage your skin, cause redness or sensitivity.  I almost never use mechanical exfoliators on my face, except for my favorite Cure Natural Aqua Gel, which is a very delicate scrub. 

Chemical exfoliators are mild chemical peels that come in two general types: AHA and BHA with various strengths. Not to be confused with putting battery acid on your face, chemical exfoliators can be even gentler than traditional scrubs. Most of chemical exfoliants are toners or lotions you apply on a clean face and don't wash off. This is an effective and safe way to mildly exfoliate your skin many times a week (instead of scrubbing 1-2 times/week), treat acne, congestion and texture issues. A mild strength chemical exfoliator can be well-suited for even sensitive skin types.

What are the differences between BHA and AHA?

AHA and BHA have a lot in common regarding smoothing or evening out your skin, but there are some unique qualities that benefit different skin concerns. Please notice AHA and BHA strengths don't go hand in hand and the you should start from a lower dosage (<1% BHA or <8% AHA) – especially if you're sensitive. Experimenting will show what works the best for you and how often you should apply: from 2 times a day – every other day, for example. Like with all skincare, please use a common sense, patch test and step away if you're irritated. Your skin shouldn't peel or burn.

AHA is short for alpha hydroxy acid, such as glycolic acid (from sugar cane), lactic acid (from milk) and mandelic acid (from almonds). Sometimes called 'fruit acids', as most commonly they can be deprived from foods, such as fruits. AHAs help getting rid of dead skin cells by loosening up glue-like lipids between the cells, revealing reveal brighter and healthier skin underneath. Shedding the dead skin cells can treat hyperpigmentation effectively. They can also plump the skin and help with wrinkling, as all AHAs have some humectant properties. AHAs do increase photosensitivity, so always use a stable sunscreen during the day!  

BHA is short for beta hydroxy acid aka salicylic acid is known acne treatment, as it can penetrate deeper in to pores and get rid of the gunk inside a pore. If you have blackheads, acne or clogged pores is BHA potentially your best friend. BHA can be drying and is often a good choice for combo or oily skin. Personally I have dry and acne prone skin, and I haven't had any problems using BHA. Salicylic acid is derived from salicin and not recommended if you have an aspirin allergy. 


- AHA is great for: loss of firmness, signs of ageing, treating pigmentation such as scars or sun spots, texture issues, dry skin. Causes sun sensitivity.
- BHA is great for: blackheads, clogged and enlarged pores, oily skin, bumps under skin

pH and concentration

The concern with picking a hydroxy acid product is pH. Too high pH and the acid won't penetrate the skin, too low and you have the risk of irritation. Usually in commercial products, the problem is the former. Also, there's the issue of concentration of acid in the product. In proper chemical exfoliants, the concentration and pH should be listed on the packaging or manufacturer's website. As I said above, you want to start from milder and work your way up, but here's an example what the pH and effective concentration for a leave-on chemical exfoliant should be:

- AHA: pH less than 4, concentration 4-10%
- BHA: pH less than 3.5, concentration 1-2%

Acids in a skincare routine

On Accutane, I don't use any chemical exfoliants to avoid irritation and peeling, but normally my routine would go something like this: I rarely use a traditional toner so I apply AHA/BHA or combo of both after cleansing, both AM and PM. If I'm using combination of both, I'll apply BHA first - assuming it's lower pH (as it should). If I'm using a Vitamin C serum like LAA, I'll apply a pH adjusting toner after cleansing, then the Vitamin C with ~15 wait time to let the product absorb, then acid(s), hydrating essences, toners and so on from water soluble to oil soluble. Recap:

Cleanse (single/double) > pH adjust > LAA Vit C + wait time > BHA > AHA > rest of routine

Use what works for you

As I said, experiment and chose your exfoliant according to your own skin concerns. I'll save the differences between types AHAs and product recommendations for a future post. I hope this introduction post was helpful and gave you more insight about chemical exfoliants and what wonderful benefits they can have for your skin! 

Have you tried chemical exfoliants? Please leave me a comment if these type of basic 101 posts are helpful or should I get into product recommendations and particulars right away.

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