Saturday, June 28, 2014

Chemical Exfoliants: AHAs & BHAs

So, Sher, what the hickity-heck are chemical exfoliants and why are they sooo much better than physical scrubs?

Oh, hey there. Glad you asked, my dear Hoojoo-ite (Hoojoo-er... Hoojoo-ian... uh... guys). First we'll cover the science, then the why it's awesome and end it all with product suggestions. Let's get into it...

What are AHAs?

AHA stands for Alpha Hydroxy Acid. AHAs are water soluable carboxylic acids used to gently exfoliate skin. pH is important when using chemical exfoliants (AHAs and BHAs)- if a product intended to be a chemical exfoliant is above a pH of 4, it essentially doesn't exfoliate. "The exact mechanism of action of these acids is still unknown; however, it has been shown that at low concentrations alpha-hydroxy acids decrease corneocyte cohesion at the lower levels of the stratum corneum and it has been suggested that this occurs by interference with the formation of ionic bonds. Essentially, by dissolving adhesions between cells in the upper layers of the skin, alpha-hydroxy acids induce shedding of dry scales from the skin's surface, commonly referred to as exfoliation. In so doing, they stimulate the growth of new skin, resulting in a rejuvenated, fresher complexion." To break it down, AHAs dissolve the glue holding dead skin cells together.

AHAs work well in treating photoaging (e.g. fine lines), hyperpigmentation (e.g. Post Inflammatory Hyperpigmentation or Melasma), and acne (i.e. by addressing keratinocyte plugging which is one route of acne pathogenesis). Furthermore, AHAs are humectants (lactic acid being the most humectant of the bunch). What this means is that AHAs are able to draw moisture into the skin. So they're absolutely fabulous for those with dry skin. Some AHAs to look for in your skincare arsenal are: Citric Acid, Glycolic Acid, Lactic Acid, Malic Acid, Mandelic Acid, and Tartaric Acid.

Of course when using an AHA, one must be careful to incorporate them slowly. The higher the concentration, the more potental for burning and irritation. Also AHAs are photosensitizing. Which means that your skin is now more sensitive to UVRs which could result in easier burning and darkening of hyperpigmentation, soooo... to the sunscreen!

A word of warning for those of color: when using AHAs, there is an increased chance of complications. Now this is just for cases when an AHA is used in a clinical setting (i.e. 20% glycolic acid) and reactions when using low, OTC preparations are rare. However, this is absolutely something you need to be aware of. These complications include (but are not limited to) appearance of dark pigmented skin blotches and skin irritation. So as always- patch test, patch test, patch test. If you notice any of these complications occuring in your skin, discontinue use of the product. Something to keep in mind as well: glycolic acid is generally considered one of the more well tolerated AHAs for darker skinned individuals.

What are BHAs?

BHA stands for Beta Hydroxy Acid. BHAs are oil soluable carboxylic acids. Salicylic acid is the most commonly known BHA although it is not technically a BHA. Thus in lieu of going into detail about BHAs, we will go into detail about salicylic acid.

Salicylic acid belongs to the same drug class as aspirin (salicylates); so if you're allergic to aspirin, don't use salicylic acid. This familial connection is also why people think applying a paste of aspirin will work in the same way as salicylic acid for their acne- it doesn't. To work in an exfoliant fashion, salicylic acid must be at a certain pH (below 4). When mixing aspirin into a paste, you can't be sure of the pH. The best you can hope for is some anti-inflammatory action- that is, of course, if you don't burn yourself in the process.

"Salicylic acid behaves differently on [the] skin than other [hydroxy acids], presumably due to its phenolic hydroxyl attachment that renders the hydroxyl acidic rather than neutral." "Salicylic acid facilitates desquamation by solubilizing the intercellular cement that binds scales in the stratum corneum, thereby loosening the keratin." The keratolytic effect of salicylic acid allows for the shedding of the horny outer layer of skin (and thus exfoliation). Salicylic acid also has a mild antiseptic action as well as an anti-inflammatory action.

In the treatment of acne, the exact mechanism of action with regards to salicylic acid is unknown, but it's believed that the drugs' keratolyic and anti-inflammatory actions are what allow it to be so effective. Moreover, salicylic acid may allow other drugs to penetrate further and it may have a comedolytic effect. Essentially salicylic acid breaks up comedones or 'degunks pores.'

Now if all of that was too much to read- fret not. I have made a little cheat sheet highlighting the differences between AHAs and BHAs so you can choose what will work best for your needs. And remember guys, if you wanna use both at the same time, you can. In fact, some of the product suggestions at the bottom contain both AHAs and BHAs.
(go ahead and spread this honey all over the internet. I don't mind. Just leave the link back when you do, okay? kisses)

Some products that work to exfoliate as well are retinoids and phenol solutions... but that's a subject for another post.

When using chemical exfoliants there is a risk of giving yourself a chemical burn. If rinsing with water doesn't cut it, a great way to neutralize chemical exfoliants (in case you decide not to patch test for whatever awful reason and just slap on the product) is a solution of baking soda and water. THIS IS BASICALLY (ha) THE ONLY TIME IT'S OKAY TO APPLY BAKING SODA TO YOUR SKIN. A solution of baking soda (1/2tsp) and water (1cup) will be alkaline which will neutralize the acidic exfoliant you've applied and stop the burning immediately. Keep that in mind if things get crazy. It's also great for stopping the burn when you toss your cookies after a crazy night of partying. [#Hoojoo Life tips]

Why you should use them (instead of physical scrubs)

Not to overstate the obvious, but physical scrubs are crazy, crazy harsh. Using products with jagged pieces in them tears into the skin, opening up avenues for bacteria to enter and create horrible acne problems. It's like trying to wax your 1972 cherry Chevelle with sand. An example of this is St. Ives Apricot Scrub. Don't use this on your face. Ever. Unless you hate yourself. Another example? Lush's Ocean Salt Scrub. Don't put these on your face guys. You might think you're helping out your face by scrubbing away flakes and bacteria, but the reality is that you're actively ripping up and destroying your delicate skin... and making the flakes worse.

Now obviously this is a controversial topic due to how popular tools like the Clarisonic are. It's expensive, it's a cult product, and people love it fanatically- trust me, I get it. Frankly, it's much more gentle on your skin to use chemical means to exfoliate. And more often than not, use of chemical exfoliants make your skin look so much better than a physical exfoliant ever could. HOWEVER (listen! listen!), careful use of the Clarisonic is ok. I'm talking between 2-3 times a week. Using it everyday (or Odin forbid, twice a day) will wreck your skin. Horrifically. You should not be breaking out from a Clarisonic (that breakout -it gets worse before it gets better- fallacy is bullcrap and you're donking up your skin hardcore by continuing to use the Clarisonic). If your skin looks raw/scaly/patchy/flaky, you are over using the Clarisonic and you need to put. it. down.

Quick Rundown on Getting Started
Now all of this information might be rather overwhelming. You might be thinking okay, this is nice and everything, but where the puke do I get started? You're going to want to start with the most gentle of options. Lactic Acid has one of the largest molecular structures and thus irritates the least. Salicylic Acid is incredibly gentle as well- and any skin type/tone can use it. It does great things for acne/oily skin, but dry skin and 'normal' skin can use it, too. You can also start at lower concentrations (of any acid) or start by using a product every few days or every other day (read the included instructions with the product- frequently companies will let you know how often to use their product). In the following product recommendation, I suggest starting with something like St. Ives Exfoliating pads, Paula Choice's AHA gel, TonyMoly Apple Tox, or Stridex. These are all very gentle options.

Also you should know that a 'purging' stage (really, an adjustment period) can happen with chemical exfoliants. So you may see things get worse before they get better. I highly suggest giving products at least a month (or two, really) to see if it is right for you. If you are still purging (and purging badly) months after starting use, it's time to move on to something else. FYI, the reason there is an adjustment period is that chemical exfoliants change the way your skin operates/behaves. You won't "purge" from a physical exfoliant (like a Clarisonic or a scrub).

Alright! That's it for the science. Sick of the rambling? Ready for some product suggestions? Awww yeah, I got you. ;)

Glycolic Acid
Alpha H- Liquid Gold
Alpha Hydrox- 14% Glycolic Acid Swipes (actually, anything by Alpha Hydrox)
Avene- Cleanance K
La Roche Posay- Mela-D Pigment Control
Makeup Artists Choice- Gly-luronic Serum
Paula's Choice- Skin Perfecting AHA gel
Peter Thomas Roth- Un-Wrinkle Peel Pads

Lactic Acid
Arcona- Brightening Drops Serum
DHC- Renewing AHA Cream
Garden of Wisdom- Lactic Acid 8% Exfoliant Pads
Garden of Wisdom- LactiSen 2% Gentle Gel
St. Ives- Scrub-Free Exfoliating Pads

Malic Acid
TonyMoly- Red Appletox Honey Cream

Mandelic Acid
Garden of Wisdom- Mandelic Acid 10% Serum
Makeup Artists Choice- Mandelic Acid Serum
Makeup Artists Choice- Mandelic Acid Toner

Salicylic Acid
La Roche-Posay- Effaclar Clarifying Lotion
Makeup Artists Choice- 3% Beta Hydroxy Serum
Olay- Age Defying Classic Night Cream
Paula's Choice- Skin Perfecting BHA Liquid Exfoliant
Paula's Choice- Clear Extra Strength Anti-Redness Exfoliating Solution [REVIEW]
Stridex- Max Strength 2% Salicylic Acid (attention: it comes in the red box- the one in the red box is the ONLY stridex product at the right pH. The rest of them have a pH that is too high and are therefore useless)

Point of interest, I purposely left out really intense chemical peels because I will be doing a post on chemical peels later. You do not want to just jump into crazy peels- I know you want to to lighten your hyperpigmentation BUT RESIST THE URGE! Chemical peels are hella serious (yes- hella. serious.) and you need to be well educated before starting them. So be patient grasshopper and wait for the main post. ♡

So that is it. Obviously this isn't every single product available that's effective. If you're not sure whether the chemical exfoliant you use (or want to buy) is effective, you can leave a comment in the doobly-doo asking me if it is. OR! You can try e-mailing the company yourself about the pH of the product (since I gave you efficacy pHs above).

All the links bolded are products I personally have used (or currently use) and love. The rest are products I know are effective I simply haven't had the chance to try yet. I tried to include every great product I could for everyone around the globe and use websites that are both trust worthy and ship internationally (since more than just North Americans visit this here blog). If you have trouble finding an exfoliant that works for you/you like, please leave a comment in the doobly-doo with your location and what you would like and I will try to help you the best I can. ♡

BONUS ROUND! If you are a new Paula's Choice (PC) customer and you would like to get 10 dollars off your order- click on this here link. PC has a referral program (so every person you refer gets 10 dollars off their order and you get a slice of the pie as well). Right now it only works for North Americans (sorry international buddies) but they're working on rolling out a global referral program. Obviously you do not need to use this program at all if you're uncomfortable with using it and all the links I've used are unaffiliated and simply link you to the products. PC is a great company and I will recommend them over and over again. But if you do decide to use it, not only do you win my undying love and affection but you're helping all the people who read (ooh ahh). I really hope to get to the point where I can make beginner's skincare care packages and by using that link, you help me get closer to that dream.

So that is that for this exciting episode of Hoojoo Skincare. See ya 'round next week.

Unlinked information was sourced from this book:
"Alpha Hydroxy Acids." Handbook of Cosmetic Skin Care. London: Informa UK Ltd, 2009. 148-154. Print.

***there are affiliate links in this post. If that makes you uncomfortable, don't worry. You can google the name of the product and purchase from your purveyor of choice. Just please keep in mind that affiliate links cost you nothing but help me keep running this blog. <3***


  1. Educated explanations that kept me entertained with your witty commentary. Thanks for this post! It was a great, informative guide. (:

    1. Witty? Oh, well thank you. <3 I do try. :)

  2. I've seen mixed thoughts on whether you need to wait 20-30 minutes after applying either AHA/BHA or both before resuming with the rest of your skincare. What are your thoughts on 1. if you need to wait and 2. if so how long?

    1. You know I really haven't seen any literature on whether or not you SHOULD wait. Honestly I've tried it both ways and I really don't notice a difference. I'd say, test it (one week waiting 20 minutes, one week only waiting for the product to dry) and do what works best on your skin. :)

  3. Thank you. This was an informative, comprehensive, and enjoyable to read write-up.

  4. Omg this is amazing. I get overwhelmed REALLY easily so I don't really know what I'm going to go with here. But, should I patch test where I am most sensitive? I have pretty acne prone skin and a lot of PIH, so I am interested in AHAs and BHAs, but don't want to dive in but rather wade slowly :)

    1. First you'll want to do an allergy test somewhere, like your arm. If you develop a rash or an allergic reaction within 24 hours, you'll know not to use the product. When you're testing a product to see if it reacts poorly with your skin, you'll want to pick a spot on your face that rarely gets acne. So that if you do develop acne, you know it's the product- and not anything else.

      If I were you, I would try the St. Ives pads or the Stridex. Those are really beginner friendly. :)

  5. Thank yo so much :) I appreciate scientifically sound posts about skincare with citations to back them up! Instead all you see these days are "chemicals are evil" without anything to back up their argument.
    I love what you're doing and continue doing so :)

    1. Aww, thank you. What a sweet comment. <3

  6. (Copied from my reddit post because I wanted to let everyone know)
    I've actually shown it to friends who were wondering about exfoliating. And definitely my mom; she's been trying chemical exfoliation and ended up using a BHA when she was really looking for the results of an AHA. My explanation didn't really click with her until she saw your post and that super helpful cheat sheet .png! Thank you!!

  7. Hi,
    I know you made this post some time ago but here it goes anyway....
    You have said that AHA/BHA's alter the way our skin operates, does this mean that if I were to use these products for some time and then (for whatever reason) stop using them my skin can't go back to operating normally? Would my skin be permanently dependent on these products for the skin renewal process? Or would it be able to go back to operating normally but not as well as it was operating before? If I discontinue would there be another adjustment period where my skin starts operating normally without help from the products?

    1. Basically what AHAs & BHAs do is they make your skin better at their job (allowing shedding to happen -faster-). So if you were to stop using a chemical exfoliant, your skin simply 'goes back to normal;' so no, it won't be operating as it had been (faster). It simply goes back to its pre-exfoliant state. And no, there won't be another adjustment period. You might notice some dulling or you might start getting break outs (as BHA's help fight acne, for all the reasons you read above).

      Lucky for you, I have my settings such that I get e-mails for new comments. ^__^ Hope I clarified things. <3

  8. This comment has been removed by a blog administrator.

  9. You removed my comment and just edited your post to update? I was just asking a question, and I thought you could have replied to me rather than just updating your blog.

    1. To be honest I really don't remember what your question was. As you can see I typically reply to comments, not simply delete them. I must have misunderstood your question.

  10. I've seen you do typically reply, which is why I was surprised and posted again. I was asking about Stridex, but you've since updated this page to specify that Stridex in the red box is the only Stridex with the correct pH for exfoliation. That's what I was asking. Previously you didn't have that detail; possibly you mentioned other Stridex as being suitable to exfoliate? I can't exactly remember now.

  11. Hi, thanks for the informative post. I see you wrote salicylic as an exfoliant should have a ph level under 4, what about salicylic toners? Should they be as close to the skin's natural ph level (5.5)?

  12. People with stretch marks have had success with using glycolic acid treatments

  13. Hi. Im a beginner exfoliant user. From everything ive read, those tell me that we need to exfoliate every week and every day (with ph n concentration less than weekly exfoliant). But so far, I only get the idea of daily exfoliate with some products like pixy glow or clinique clarify. Since I think weekly efoliate is necessary, I browse over n over n I think would like to do it with some product with high salicylic acid (yet affordable) such as aspirin. But that acid needs to be in exact ph (3 to 4) to works. My idea is I will mix aspirin with some toner that have ph 3 or 4. So, what do you think about my thoughts is that gonna works? And what do you think about that ritual ive explained? And do you know products that have high bha that indonesian can get and affordable? My face is normal combination and acne prone. Thank you in advance..

  14. Hi. Im a beginner exfoliant user. From everything ive read, those tell me that we need to exfoliate every week and every day (with ph n concentration less than weekly exfoliant). But so far, I only get the idea of daily exfoliate with some products like pixy glow or clinique clarify. Since I think weekly efoliate is necessary, I browse over n over n I think would like to do it with some product with high salicylic acid (yet affordable) such as aspirin. But that acid needs to be in exact ph (3 to 4) to works. My idea is I will mix aspirin with some toner that have ph 3 or 4. So, what do you think about my thoughts is that gonna works? And what do you think about that ritual ive explained? And do you know products that have high bha that indonesian can get and affordable? My face is normal combination and acne prone. Thank you in advance..