What are AHAs, PHAs, and BHAs?

What are AHAs, PHAs, and BHAs?

AHA, PHA,&  BHA this can sound like some crazy scientific jargon. But AHA, PHA, and BHA are all acids that work to brighten your complexion. I know what your thinking, I don’t want to put acid on my skin and melt my face off. Don’t worry these acids work as mild exfoliates to reduce acne, fade dark spots and brighten your skin. But what exactly do these acronyms mean and which should you be using?

The Chemical Structure of Lactic Acid a very common AHA


Alpha Hydroxy Acids or AHAs

Let’s start alphabetically and start with Alpha Hydroxy Acids or for short AHAs. If we look at the structure above the name alpha hydroxy acid comes from a carboxylic acid with a substituted hydroxy group on the second carbon (which in organic chemistry is referred to as the alpha carbon). What does that mean? It is a very very stable polar acid. As a result,  it occurs naturally in milk, fruits, and sugars. AHAs can also be made very easily synthetically. The thing about our skin is it sheds. (I know it sounds gross) But we shed the top layer of our skin regularly to show nice new baby soft skin. What makes AHA’s so useful is it increase cell turnover. Basically, they make you shed a lot of skin faster and more regularly. AHA’s are the most common acid you’ll encounter in your skincare. What makes AHA’s so unique is that it can penetrate the upper levels of your skin and really improve your complexion. It gets rid of those top layers of your skin with all those imperfections! AHAs can be used to reduce the appearance of fine lines and wrinkles as well.  For instance, the most popular AHAs are Glycolic acid and Lactic acid. You may find these ingredients in a myriad of skincare products. What is also beneficial about AHA’s is that the hydroxy group helps attract water. Not only do AHAs shed the top layer of your skin but it moisturizes it at the same time.

Basic Chemical Structures of BHAs

Beta Hydroxy Acids

So next we have Beta Hydroxy Acids. If we look above at the structure of Beta Hydroxy Acids they have a carboxylic acid with a hydroxy group on the third carbon. ( Which as you guessed in organic chemistry is referred to as the beta carbon.) What does that mean? Having more carbons in the structure separating the functional groups (the OH groups)  makes the compound less acidic and polar. As a result, synthetic BHA’s are harder to create and are less acidic to your skin. So you will see less skin turnover than with AHAs. An acid with high polarity interacts with water more than oil. Therefore, BHA tends to interact more with oil than water. As a result, BHAs penetrate the upper layer of your skin and breaks down oil buildup in your pores. One of the most common BHA is salicylic acid. (Every pubescent teenager is aware of salicylic acid!) This acid helps breakdown and stop the appearance of acne. Much like AHAs, BHAs moisturize the skin by attracting water due to their OH groups. Think of BHAs as more of pore cleansers that give you an evener complexion over a long period of time.

Basic Chemical Structure of PHAs

Poly Hydroxy Acids or PHA

So I know what your thinking. The chemistry of AHA and BHA were simple and here we have a literal beast. Don’t worry, what your looking at isn’t a super crazy molecule only a chemist would understand Polyhydroxy acids or PHAs are pretty simple. The Latin word “poly” means many. (Don’t worry I’m getting to the point) PHAs are basically Alpha hydroxy acids but with extra hydroxy groups attached to them. What does that do? It makes PHA’s less acidic versions of AHAs. PHA’s are useful for people who have really sensitive skin. Basically,  if your skin reacts or turns really red when you use an AHA you can use a PHA. PHA’s are really moisturizing too just like AHAs. The only drawback fo PHAs is since they are less acid that makes you will have to use them for longer to see results. They work a lot slower than AHAs. But if that keeps you from burning your skin off then its definitely worth it! 

AHA, BHA and PHA are all important acids to improve skin complexion. It is important to use these acids correctly for more beautiful and brighter skin! So now you are basically a chemist. One thing to remember about AHA, BHA, and PHas is you are using them you should also be using a sunscreen every day. (but your already using sunscreen everyday right?) Since these acids are causing your cells to turnover faster it is showing new aby layers of skin. Which need extra sun protection. If you are using AHA, BHA and PHAs without sunscreen your basically wasting your money because you will be damaging your skin more with UV rays

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