The Ultimate Guide to Acids Found in Skincare

The world of acids can be overwhelming – they’re a lot of them out there that all do similar things but of course they all have subtle differences. However, those subtle differences can be useful to know about when it comes to shopping for and taking care of your skin. 

You may not have known this, but all the acids used in our skincare fall into one of three groups; AHA’s, BHA’s, and PHA’s. I know it sounds too scientific but trust us, you probably know a few of them so don’t feel overwhelmed!⁣ To help, we put together the ultimate guide together for you to reference anytime!


AHA, or Alpha Hydroxy Acids, is a group of acids that are naturally found in fruit, milk, sugarcane, etc. It is the “first generation” of the acids and can easily penetrate deep into the skin because of their small molecule size. Acid’s that fall into the AHA category are:

Glycolic Acid – One of the most common forms of AHA (and the most researched). Glycolic acid has one of the smallest molecular weight of all the AHA’s, which means it is very effective in penetrating deeper into the skin. Glycolic acid is also one of the most hydrating acids of them all! This acid is best for people with dry skin but is most likely going to be too irritating for someone with sensitive skin.⁣

Lactic Acid – Another form of AHA that helps to exfoliate the skin. Lactic acid has a larger molecular weight, therefore, it will provide a more superficial exfoliation. This means it is incredibly effective at smoothing and brightening the skin, and is less sensitizing than other AHAs. 


BHA, or Beta Hydroxy Acids, we predominantly use salicylic acid is the “second generation” of acids. This acid (which can be found in aspirin!) naturally occurs in the white willow tree and contains anti-inflammatory properties. BHA’s are fat-soluble and also have very small molecules so they are able to work deep within your skin to help exfoliate and dissolve oil. Acid’s that fall into the BHA category are: 

Salicylic Acid – Salicylic acid is the most common form of BHA. It actually exfoliates from within the pore, making it especially effective for those struggling with acne, congestion, or texture issues. 

Citric Acid – While primarily classified as an AHA, some formulations of citric acid are BHAs, too. In it’s AHA form, citric acid role is to balance skin’s pH level, however in its BHA form it is primarily used to dry out excess oil and exfoliate deep pores. 


PHA or Poly Hydroxy Acids are slow working acids such as gluconolactone and lactobionic acids. They have large molecules sizes, and therefore cannot penetrate the skin deeply and only work on the surface. Some might think, what’s the point of that? There are actually a few advantages! These mild acids are perfect for all types of sensitive and/or dry skin conditions such as eczema or rosacea. In addition to this, PHA’s don’t make the skin more photo-sensitive, or susceptible to damaging UV rays.⁣ Acid’s that fall into the PHA category are: 

Gluconolactone – is a natural substance that can often be found in creams and serums. It has all the benefits of AHA’s while still being suitable for sensitive/dry skin.

Lactobionic acid – Part of the PHA family and non-irritating, this patented ingredient is known as a “Bionic Acid” and is derived from natural sugars. Lactobionic acid is a potent antioxidant that has been shown to target naturally-occurring, skin degrading enzymes to help maintain a youthful look. Best for very dehydrated, parched and dry skin types. 

For More Information:

For more information about acids, please contact us at ZONA Med Spa. Or book a consultation online by clicking here.

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