We take a deep dive into what AHA/BHA is, what it does and how to incorporate it into your routine
Alpha-Hydroxy Acid / Beta-Hydroxy Acid
ˈælfə-hydroxy ˈæsɪd
AHA’s and BHA’s are types of hydroxy acids. AHA stands for Alpha-hydroxy Acid, and BHA stands for Beta-hydroxy acid.
They are chemical exfoliators, that peel away the dead skin cells on the upper skin surface.
Overview
AHA and BHA’s assist the shedding process of dead skin cells. Over time this process slows and AHA/BHA can be a great help. A build of dead skin can result in dry, flakey, dull skin with clogged pores and the potential for acne if P. acnes bacteria build up occurs.
AHA and BHA have similarities and differences; both must be formulated within a narrow pH range between 3 and 4, both diminish the look of lines and wrinkles, make skin look and feel firmer, hydrate skin, improve texture and dullness.
They differ in the fact that AHAs are water soluble and therefore work on the skin surface. This is better suited for normal to dry, sun damaged skin. AHA’s aid moisturising, and can reduce visible sun damage.
BHA works on the surface and in the pores, so works well with normal to oily skin. It works well on bumps, acne and enlarged pores. Despite its powerful range of ability it is calming to the skin and works well on sensitive skin and redness and rosacea.
Types of AHA:
- Citric Acid
- Glycolic Acid
- Lactic Acid
- Malic Acid
- Mandelic Acid
- Tartaric Acid
Types of BHA:
- Salicylic Acid
- Citric Acid (some formulations are BHA)
Purpose
They are a type of chemical that helps to gently exfoliate the build up of dead skin, leaving soft hydrated skin underneath.
They work to unglue the bonds holding the layer of dead skin, and these can then be removed with gentle cleaning or through a natural shedding process.
They reduce inflammation, signs of aging such as wrinkles and fine lines, minimise pores and even skin tone and overall skin texture.
Benefits
Deep exfoliation and may reduce acne, bumps, texture issues and some rosacea related redness.
AHAs help with dry skin relief and anti aging. BHA’s help with acne and associated conditions.
BHA’s are primarily used for acne and sun damage as it goes deep into follicles to remove clogged pores and dry out excess oils
Drawbacks
Take care when using with dry or sensitive skin. Work up gradually to avoid irritating your skin. In some cases can cause stinging or burning sensations. These will usually pass, lower your concentration and use frequency.
How to Use
Use of AHA/BHA’s are down to personal preference and experimentation. To avoid skin irritation when beginning AHA/BHA treatment start with a slow schedule. Apply every other day and build up. For sensitive skin begin once a week. Start with a product concentration of maximum 10%-15% AHA.
Products
Products that contain: AHA:
Products that contain: BHA
References:
Fact-check: Why does pH matter for AHAs and BHAs? | Lab Muffin Beauty Science (2014). Available at: https://labmuffin.com/fact-check-friday-why-does-ph-matter-for-ahas-and-bhas/
Understanding Skin Care Product Ingredients (2020). Available at: https://my.clevelandclinic.org/health/articles/10980-understanding-the-ingredients-in-skin-care-products
Wang, X. (1999) "A theory for the mechanism of action of the α-hydroxy acids applied to the skin", Medical Hypotheses, 53(5), pp. 380-382. doi: 10.1054/mehy.1998.0788.
https://pubmed.ncbi.nlm.nih.gov/10616036/