The debate on natural versus synthetic AHAs has
ranged for several years. Basically, the therapeutic
index is the ratio of stimulation to irritation. Accord-
ing to the acidifying property of AHAs, they have a
potential to irritate the skin. However, their irritation
potential is coupled with the ability to stimulate cell
renewal. It has been found that the therapeutic index
of the natural AHAs surpasses that of the synthetic
AHAs. It is likely that the natural AHAs contain nat-
ural soothing agents which can reduce the irritation
potential, and not interfere with stimulatory activity
of AHAs [30]. Coupled with using the transdermal
patch to control the topical delivery of the natural
AHAs, irritation to skin caused by these compounds
should be much lesser.