Exfoliation is an integral part of keeping skin smooth and clear, free from debris that accumulates in the pores. It removes dead surface cells that dull the complexion, brightens pigmentation and helps lighten post breakout marks. However, the primary benefit of regular exfoliation is that exfoliation boosts cell turnover and stimulates skin repair.
AHAs (alpha hydroxy acids) are considered top down exfoliants. That means they dislodge dead cells on the skin's outer layers and in the pores by dissolving the bonds that stick these cells together and keep them attached to the skin's surface. They offer immediate results by providing smoother, softer skin.
Retinols are considered bottom up exfoliants. They work by filtering through the skin and stimulating cell production at the base of the epidermis. As the new cells rise up to the surface they push off older cells, leaving cell layers more organized and youthful looking At the same time retinols send chemical messages to fibroblasts in the dermis to produce new collagen and elastin and supports the dermal matrix that provides skin firmness and mitigates fine lines and wrinkles.
For optimal results it is advised that you adopt both a top down and bottom up approach to your exfoliation regime.