Updated: Feb 23
There seem to be a lot of misconceptions about peels - given the name, a peel sounds kind of scary if you don't know what that really entails. The word itself evokes mental images of sheets of skin peeling off your face, and red raw skin - not an attractive thought.
In reality though, despite the somewhat scary name, most peels are a very un-scary, and very effective treatment for many things including acne, breakouts, scarring, pigmentation and fine lines/wrinkles.
Most "traditional" peels are acid-based - again, scarier than it sounds (remember, "ascorbic acid" is just vitamin C!) - although some are formulated with vitamin A instead of, or combined with acids.
There are a plethora of acids to choose from when selecting a peel solution - each with their own properties and specific benefits to the skin. You might be familiar with some of them: glycolic acid, salicylic acid, lactic acid, mandelic acid - to name a few.
How Acid-Based Peels Work (this applies to most peels)
Put in the simplest terms, acid-based peels work by breaking down the top layer of skin, causing it to shed. But let's dig a little deeper.
Your skin cells are held together by little bonds connecting the cells to each other - you can think of these like the "glue" that holds your skin together. Acid-based peels break down this "glue", thus freeing the skin cells so that they may freely shed from your skin - hence, the peeling.
The breaking-down action of peels occurs at different depths in the skin, depending on the acid used. Acids with a larger molecular size (for instance, lactic acid) can't penetrate very deeply into the skin - they are simply too large. These acids work mostly superficially on the skins surface, tend to cause a less peeling, and are typically the least irritating to the skin. Acids with a smaller molecular size, like glycolic acid, penetrate deeper into the skin, tending to cause more peeling and be more irritating to the skin.
Which Acids Do What?
Lactic Acid is usually tolerated pretty well by the skin. It's hydrating, because it facilitates the release of NMF (Natural Moisturising Factor - the skin's naturally produced, lipid-rich moisturising factors), and its exfoliating effects result in improvement in skin texture, and evening out of skin tone/lightening of pigmentation. It's a great acid for skins that are sensitive, or haven't used acids before. It's also a great supportive acid when combined with other acids in a peel solution (most peels contain a combination of multiple different acids).
Glycolic Acid penetrates deeper than lactic acid, due its smaller molecular size - for this reason, it can be more irritating to the skin. Its deeper penetration results in more peeling. Again, it is wonderful for treating pigmentation, and it also has a plumping effect on the skin so it helps to reduce the appearance of fine lines and wrinkles.
Salycilic Acid is a personal favourite of mine. This acid is fantastic for breakouts, excess oil production and acne, as it penetrates deep into the pores of the skin breaking down oil, and dead skin cells that can clog/congest the skin. It's also anti-inflammatory, making it ideal for inflamed breakouts/acne and it helps to reduce redness in the skin.
Mandelic Acid is another personal favourite. Mandelic acid is my absolute go-to acid for treating post-inflammatory pigmentation (the red/pigmented marks or spots that linger long after breakouts and acne have healed). Mandelic acid is safe to use on dark skin, and like salicylic acid, it has anti-inflammatory properties.
There are other acids that are commonly used in peels (Kojic, Pyruvic, Azelaic, Trichloroacetic Acid), but the above acids are typically the most commonly used.
Vitamin A Based Peels
The mechanism of vitamin A peels is quite different to acid-based peels - they essentially work from the inside out. To understand how vitamin A peels work, it's important to understand the basic process of skin cell turnover.
Essentially, at the basal (base) layer of your skin, new cells are being formed all the time to replace the old ones. When a new cell is formed, it gradually rises up through the layers of your skin, all the while growing older and tougher (keratinising), and eventually ending up in the outer layer of the skin (the stratum corneum). At this point, the aged, dried out cells act as a protective barrier for your skin until they fall off and are replaced with the next "batch" so to speak.
The rate at which this whole process happens varies largely depending on age, as well as your skincare, diet, and other lifestyle factors. The "ideal" rate of skin cell turnover is 28 days - as in, your skin cells live for 28 days from being produced to shedding off the top layer of your skin.
When you are in your teens, cell turnover rate can be as fast as 14 days. When you're in your 40's, 50's, and 60's this rate slows down dramatically (up to 75+ days) resulting in those skin cells sitting on your skin for longer and longer, which ultimately negatively affects the health and appearance of your skin.
Vitamin A increases the rate at which new skin cells are produced, speeding up skin cell turnover. This is the case when you use a low strength vitamin A serum at home. A vitamin A peel works by delivering a high dose of vitamin A to the skin, causing a dramatic short term acceleration in cell turnover. The rate of cell turnover speeds up to a degree that the outer layer of skin begins to shed due the speed of the new cells coming through, pushing old cells off.
Vitamin A has some other pretty significant benefits for the skin too:
Vitamin A reduces and regulates oil production in the skin - so for those of you struggling with excess oil production and its negative effects (blackheads, breakouts, acne, enlarged pores), vitamin A is your new best friend.
Strengthens + Thickens Fragile Skin
Vitamin A increases collagen production in the skin, plumping, strengthening and thickening fragile or lined/wrinkly skin.
Fades/heals Inflammatory Pigmentation
Vitamin A is super effective in fading and healing post-inflammatory pigment (the residual red or pigmented marks that stick around long after a breakout or acne has been and gone). It promotes healing in the skin, and increasing cell turnover helps the pigment to fade faster.
So what actually happens w