Acids & Exfoliants - What are they & what do they do?

We all hear about how we should be using a mix of acids on our skin to promote healthy, glowing skin and prevent aging. However, before you start adding acids into your skin care routine, it’s important that you understand the basics of acids: what are they, what do they do, benefits, what should we be aware about?


Let’s break it down.  Hydroxy acids are acids that have anti-aging and skin soothing effects. Hydroxy acids are actually a family of chemicals: α-hydroxy acids (AHAs) and β-hydroxy acids (BHAs), combination hydroxy acids (CHA) and polyhydroxy acids (PHAs).

• AHAs - glycolic, lactic, citric, magic, mandolin, tartaric acids
• BHA: salicylic acid
• CHAs are formulations made of salicylic acid combined with an AHA
• PHAs are larger molecular weight AHAs.

For the purposes of this blog post, I will be focusing on AHA and BHAs.
AHA and BHA are really just broad terms with little differing significance (to anyone other than a chemist). But wait - I think it's still important to educate yourself about the difference between BHA & AHAs and essentially, what's going on your face.

Before we understand the difference between AHA and BHAs, let’s consider our skin - our body’s largest organ. Our skin’s outer layer is composed of damaged skin as well as dead skin cells, which slough off over time. Younger skin is more efficient at this process via exfoliation, which stimulates the growth of new skin cells at the deeper level. But as we age, our skin gets “less good” at this - so the outer surface of our skin starts to thicken with a build up of damaged skin, scar tissue & dead skill cells. This type of surface makes the skin appear dull and also decreases elasticity; lines and creases begin and eventually, deeper wrinkles appear. When we exfoliate, we peel off surface skills to allow new skin cells to regenerate and emerge, thus giving us the healthy, glowing skin we strive for!

How do AHA & BHAs work?
AHA and BHAs loosen the glue holding the skin cells together, thus causing the top layer of the skin to exfoliate. This allows for:

• improved skin tone and texture
• reduction in fine lines and wrinkles
• fading of age spots
• helps to control oily skin and acne associated problems

AHAs come in different types of products, such as cleansers, moisturizers, and skin treatments.

AHA & BHAs are similar because they both:

• diminish the look of lines and wrinkles
• help make skin look and feel firmer
• hydrate
• improved the look of dull skin and uneven skin tone
• smooth out rough texture of the skin

AHA & BHAs are different because:

• There is a difference in chemical structure (BHA occurs in the beta position on the carbon chain; AHAs occur in the alpha position). But for our purpose….
• The alpha hydroxy acid group consists of a variety of different acids; the beta hydroxy acid group consists of salicylic acid.
• Salicylic acid (BHA) is unique among all of the hydroxy acids because it can "enter the milieu of the sebaceous unit, inducing exfoliation in the oily areas of the face" (Draelos, 2000, p. 154). On the other hand, AHAs cannot exfoliate optimally in the oily areas of the face (i.e. usually the central forehead, nose, and chin areas). Therefore, their activity in acne treatment isn't as great, nor do they produce peeling on oily skin.
  • Essentially, this means that AHAs work on the skin’s surface and are water soluble, while BHA is oil soluble and works on skins surface AND inside the pore. So, BHA works well for normal to oily skin prone to bumps blogs blemishes and enlarged pores. BHA is also good for rosacea because it has natural skin calming properties. Essentially BHA is a well rounded ingredient.

How can you tell the effectiveness of a product?

• The type of AHA used
• pH level & concentration
  • The lower the pH (the higher the acidity) the more rapidly the product is absorbed into the skin
    • But keep in mind, as an acid, the greater the burning sensation…
  • pH can be controlled by altering the concentration of the hydroxy acid
    • For example, 10% glycolic acid is x4 more acidic than 1% glycolic acid
• cosmetics’ formulation

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I hope this blog post provided you with valuable information about acids. There's always so much to learn, and I am happy to be learning and sharing knowledge at the same time. 

PS. Remember to always wear sunscreen - regardless of whether or not you are using acids in your routine; it is the best thing you can do for anti-aging!



References:

Cates, N. D. (1998). Uncovering a new you: AHA's & BHA's. Better Nutrition, 60(6), 70-74.

Draelos, Z. D. (2000). α‐Hydroxy acids, β‐hydroxy acid, and other topical agents. Dermatologic Therapy, 13(2), 154-158.

Paula's Choice (n.d.). The difference between AHA and BHA exfoliants. Retrieved from https://www.paulaschoice.com/expert-advice/skincare-advice/paulas-choice-product-tips/difference-between-aha-and-bha-exfoliants.html

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