How to Use Lactic Acid
No one gave us a manual for taking care of our skin. So most of us have been performing roughly the same skin care regimen we started with as teens, with a few promising and expensive products thrown in here and there. If you are unsure about the efficacy of your regimen and you are not using an alpha hydroxy, this is a great place to start.
Alpha hydroxys are a chemical exfoliants with well-documented anti-aging properties, boosting collagen and elastin synthesis and increasing cell turnover. By far the most common AHA’s are Glycolic Acid (from sugar cane) and Lactic Acid (from milk). Other AHAs are citric, mandelic and tartaric acid. They act on the epidermis by loosening the keratinzation of dead cells, which causes them to bind and stick together like glue. This loosening helps dead skin cells slough, allowing newer, more youthful looking cells underneath to come through. Because they are bioavailable, meaning they are absorbed transdermally, they can also act on the dermis, stimulating and hastening production of collagen and elastin. AHAs are also known to even skin tone and texture, and to treat hyperpigmentation (liver spots).
Though glycolic acid is stronger, it is also more harsh and can cause irritation and drying for some skin. Humans do not have cell receptors for glycolic acid, rendering it an unfortunate free-radical generator. Lactic acid, on the other hand, has hydrating properties and does not produce free radicals. The dilution (percetange of acid to water) determines the strength of a mixture, however the pH is equally important. Too low a pH (3 or below) can cause irritation and burns, with no regenerating benefit, even in weak solution. A higher concentration of lactic acid (12 – 20% is an effective but not overwhelming dilution for most skin) with a pH of about 3.5 is ideal. Alpha hydroxys can be used continuously for up to 12 weeks with no diminution in effect. In other words, use AHAs for 12 weeks on, 12 weeks off.
Notes: Exfoliation, use of retinoids, and AHAs all temporarily thin the epidermis, so care must be taken when beginning an anti-aging regimen. Due to increased skin sensitivity and possible burns and permanent skin damage from the sun, always, always, ALWAYS use a broad-spectrum, 30+ sunscreen designed for face when employing AHA’s, retinoids, or any exfoliation regimen.