"It is demonstrated that skin with pH values below 5.0 is in a better condition than skin with pH values above 5.0, as shown by measuring the biophysical parameters of barrier function, moisturization and scaling." (Lambers et al.)Now, to refresh us all on pH, or potential hydrogen:
Wikipedia! That little bit about pH being logarithmic means that the small differences between pH numbers represent huge (exponential) differences in the actual acidity or alkalinity of substances.
Not only is skin in better shape when its pH is lower, but the study also estimates that skin's natural (not altered by soaps, which are typically highly alkaline) pH is even lower, putting it an estimated 4.7.
For perspective, these measures are pretty right:
But wait, you say, this study is all about skin's resident microflora. I don't want bugs on my skin!!! Ok at this point we've all seen these:
The effect of pH on adhesion of resident skin microflora was also assessed; an acid skin pH (4-4.5) keeps the resident bacterial flora attached to the skin, whereas an alkaline pH (8-9) promotes the dispersal from the skin.So if for no other reason than to keep your skin's protective bacterial colonies intact, providing you with enhanced barrier function and better moisturization, acid acid acid!
Of course we still want clean skin that can absorb the anti-aging ingredients we love so much. There's a simple way to get clean skin and still leave your skin at an appropriate pH for bacterial recolonization: toner. It's so simple I'm not going to talk about it much, except to say that all the toners we stock at the Skin Studio meet the requirement of bringing skin back down to its natural low pH, and some of them go even further.....
Further, you ask? YES, this is the tingly part of the Acids post! With so many surface benefits occurring in the 4.5-5.5 pH range, why go lower? Well, there are kind of a LOT of studies showing that stronger acids applied professionally as chemical peels clear up acne, reduce melasma about as well as laser treatment (better, in my opinion, since there is no risk of excessive pigmentation as a side effect), remodel collagen and reduce wrinkles, reduce dark under-eye circles, acne vulgaris, oily skin, textural changes, melasma, and post-inflammatory hyperpigmentation, are safe in darker skin tones.
Since I know you clicked through to each and every one of those links, I'm thinking you probably noticed the mention in several places of "preconditioning" the skin for peels. What does it mean? Easy... just like using toner regularly keeps the skin's pH low and the surface skin cells desquamated, your esthetician will probably also add in a retinoid, a barrier-maintenance product, and possibly a pigment inhibitor so that your peel treatment will progress evenly and predictably.
Results? Why, healthier skin, a thicker dermis, thinner epidermis, better texture, reduction in blemishes and pigmented lesions, firmer, and more youthful skin.