THE 101: Acid Exfoliation


Hello! If you follow me on Instagram or are one of my clients (thank you, I appreciate you!) then you also probably hear me talk about acid exfoliation often because it should be an essential for almost everyone. I've always gotten a lot of questions about how, when and why to exfoliate, so lets talk acids!  If you want to skip to my acid exfoliator reviews, click here. 


Why should I exfoliate?

Removing built up skin and increasing cell turnover is part of keeping skin looking fresh and smooth. Our skin does this to some extent naturally, but as we get older along with so many types of environmental damage, the skin's natural ability of shedding these cells slows down. Exfoliating helps in preventing clogged pores and breakouts, evens out skin tone, improves texture, reduces signs of aging like fine lines and lets your other skincare products work even better since they will have less of a barrier to get through. 

How exactly does an acid work?

Simply put, acids dissolve the 'glue' or the bonds that hold dead skin cells together. This act of breaking down these bonds promotes exfoliation at varying depths. For my technical science friends that love chemistry and want references, check this out from one of my favorite blogs.

Which type of acid should I use?

Acids can be naturally occurring, or be synthetically made. I personally think both are equally effective. If you prefer to use organic or eco-friendly products, there are absolutely acid brands in that category too! Depending on your skin type, and your skin goals, you'll want to look for products with specific acids. All skin types will benefit from AHA's and PHAs but oily and acne prone skin should use AHA and BHA, or just BHA. Experiment and see what works best for you! There are dozens of acids, but I'm going to go into detail about the most commonly found acids.

Glycolic Acid: Gycolic is the most researched and most common AHA found in acid exfoliators. It's water soluble and hydrophilic so even though it has some degreasing properties, it mostly stays away from the lining of hair follicles and pores. This a great acid for all signs of aging and normal to oily or normal to dry skin. Because of the very small molecular structure of glycolic, it also can sometimes result in inflammation on sensitive skin types. Very sensitive skin may do better with acids that have larger molecules, like lactic acid, polyhydroxy acid, or salicylic acid.

Lactic Acid: Lactic is another popular AHA, but has a larger molecular structure than glycolic which means it penetrates into your skin slower and therefore resulting in less of a chance of inflammation if you have sensitive skin. Lactic has shown to have antimicrobial benefits and inhibit tyrosinase production (which means its helpful in reducing pigmentation). This acid also functions as a humectant, making it ideal for normal to dry skin but beneficial for all skin types

Mandelic Acid: Mandelic, an AHA, has been growing in popularity. I've seen it used primarily in Asian Beauty brands for years, but recently have seen it in US brand formulations. This acid has potent antioxidant properties and is fat soluble with antibacterial properties making it great for normal to oily skin prone to breakouts.

Malic Acid: Malic, another AHA, is found in some fruits and veggies (most commonly in apples) which is why its commonly referred to as a 'fruit acid.' I see this acid often in more eco-friendly brands since its easily derived from natural sources. Malic has shown to be somewhat less effective then other AHA's so its usually combined with other acids. Its humectant properties make is great for normal to dry skin.

Azelaic Acid: This belongs to an acid group called dicarboxylic acids. Not only does it have exfoliating and antibacterial properties, but it's also shown to have antioxidant activity. Working with doctors, I have seen firsthand the miracles that azelaic acid topical prescription products have had on stubborn acne and rosacea. This is a great alternative for skin that is allergic to benzoyl peroxide. I've seen it in non-rx formulas up to 14%, and expect more formulas to start using this acid.

Salicylic Acid: Salicylic is in the BHA (beta hydroxy acid) group. It's oil soluble and lipophilic, meaning it can exfoliate in your actual pores. There are similar ingredients to sal acid, like betaine salicylate that work similarly. The antibacterial and anti-inflammatory properties makes this ideal for oily, acne prone skin types. 

Gluconolactone: This PHA (polyhydroxy acid) is part of the newer exfoliating acids and has been shown to have humectant and antibacterial properties. This is ideal for all skin types, but the larger molecular structure makes it less irritating than glycolic and worth considering for skin types that are sensitive or are on retinoids.

Other Acids :There are even more exfoliating acids in the world of skincare. Tricholocetic acid (or TCA)  and retinoic acids are used in many peels that I perform at my office, but rarely seen in leave-on acid exfoliators available to consumers. Lipohydroxy acid is a derivative of salicylic acid that has a slow penetration, but I believe it's exclusive to L'Oreal brands. Tartaric acid is another 'fruit acid' naturally found in grapes. I don't see it in many products but its considered an AHA and has antioxidant properties.

How do I use an exfoliating acid? 

Acids can come in all forms of skincare: cleansers, toners, serums, creams, or masks. I recommend using them in leave-on form since cleanser doesn't stay on your skin long enough to really exfoliate. I personally prefer acids in liquid form (serums or toners) because I find them easier to incorporate into my skincare, however you can experiment with an acid in a lotion or cream- it's really your preference. Generally lighter texture products are ideal for oily skin but any skin type can use them. Cream and lotions with acids work best for normal to dry skin. Depending on what issues you are treating and the concentration of the acids will determine how often to use it. Apply your exfoliant after you cleanse and tone. Then apply hydrating products if needed. Even though I recommend using acids at night, acid exfoliation will make your skin more sensitive to the sun, so SUNSCREEN IS MANDATORY :)

How often should I be using an acid exfoliator?

Acids with a concentration from 2% to 10% can be used daily (preferably at night) or every other night. Acids above that can be used one to three times a week. If you are thinking "Jordana, please, you're lucky if I wash my face most nights" and can't commit to adding an acid to your routine, try an over the counter peel twice a month or see an esthetician or a dermatologist for a peel! 

Who shouldn't use an acid?

If you have very sensitive skin, highly reactive skin, and/or a lot of allergies, then patch test your acid first. If you are on accutane or prescription retinoids, you probably won't need an acid exfoliant, but you can try mild formula once or twice a week. When my clients are on non-prescription retinoids, I'll usually have them use mild acid exfoliants on the nights they don't use their retinoid. I recommend getting your skin used to either a retinoid or the acid before using both. Don't apply acids over irritated skin, or active herpes/cold sores near or on the mouth. Avoid eyelids but you can experiment with using under your eyes, just stop about half inch from the lower lid. If you are pregnant or breastfeeding, ask your doctor if you should use acids. I feel most are totally safe but it's best to go over that with your doc.

How I patch test: Apply the product to one side of your lower face, near your lower ear/ jawline. Don't apply any other products over it when you patch test. Give it 24 hours to monitor for any reactions. Tingling sensations can be normal, but should subside within minutes. If all looks well after that 24 hour period, then try on your entire face. 

What acid exfoliators do you recommend? 

Reviews can be found here. Happy exfoliating!