Brief Answer:
Topical retinoids
Detailed Answer:
Hi.
Topical retinoids increase the rate of keratinocyte turnover resulting in an increased rate of follicular proliferation and differentiation. This results in decreased follicular occlusion and faster microcomedone clearance which is responsible for there beneficial effect in acne.
Retinoids loosen the bonds between these dead cells in the
Stratum corneum (SC), allowing them to let go of each other and flake off more easily, exposing the smoother, more radiant skin beneath. So I suppose it's true to say that "retinoids thin the dead layer of skin." They make the dead cell layer of the SC look more compact so that it can more easily reflect light. Alpha and Beta Hydroxy Acids (AHAs and BHAs), scrubs,
chemical peels and
microdermabrasion all have the same effect. This is the reason that you should be especially regular about using a daily sunscreen if you use any of these products or treatments, because they remove a bit of sun protection, that's normally offered by the dead skin cells.
Retinoids may thin out that dead superficial layer of epidermal skin, but they actually help thicken the living
dermis underneath. The dermis is the important layer when it comes to skin aging because
wrinkles occur in the dermis. The dermis contains structure-giving
collagen, elastin to keep skin elastic, and
hyaluronic acid (HA) to give skin volume by helping it hold on to water. Retinoids are therefore good for the skin because they prevent and reverse ageing. So that is an added advantage of using a topical retinoid.
regards