Blue Water Spa's Guide to Alpha Hydroxy Acids,
The Latest from Blue Water Spa
We borrowed this article from http://swiftcraftymonkey.blogspot.com/. There is a wealth of knowledge on this site.
Alpha hydroxy acids orAHAs come in many forms, but we are probably most familiar with the glycolic (this lovely molecule), lactic, and citric acid versions of this water soluble carboxylic acid.
I'm sure you've read a million times how fantastic AHAs are for our skin, but how do they work? The official statement is they induce epidermal effects through corneoctye disadhesion, operating by disrupting the ionic bonds between the cells so they can slough off and expose newer and lovelier cells underneath the stratum corneum, or top layer of cells. They also work as an anti-oxidant and can relieve post sun redness. All of these things make fine lines and wrinkles appear less obvious, reduce redness and inflammation, and expose new, shiny skin to the world.
AHAs work by penetrating our skin through the stratum corneum to the stratum granulosum. It acts as an exfoliant on the top layer of our skin by disrupting the bonding between the cells and allowing them to slough off, revealing those new and lovely cells I spoke of earlier.
AHA is considered stronger than BHA as it works from the lower to the upper levels of our skin, but this can work against us if too much of the stratum corneum is exposed. This can increase transepidermal water loss, so you will want to add extra humectants and occlusion ingredients to any lotions including AHA. This can also lead to thinning of the stratum corneum, so you will want to make sure if you are using AHA products, you're keeping your skin well protected. Always use a sunscreen if you are using AHAs in your products because AHAs can make you sun sensitive (even if you're using it in night cream, as taking the moisturizer off won't necessarily make you less sun sensitive!). And note that because AHAs actually penetrate our skin, they will bring other active ingredients with them, which means some extracts and other wonderful things will be more effective as they penetrate the skin
In one study, a lotion with 12% lactic acid increased the appearance of rough skin, increased exfoliation, and increased skin hydration by 33%. In another study, a 10% glycolic acid cream showed the exposed skin had a pinkish colouration with a shiny smooth surface.