Final answer:
The main difference lies in the action method; mechanical exfoliants remove dead skin cells through physical scrubbing, while chemical exfoliants dissolve them through chemical reactions.
Step-by-step explanation:
The main difference between a mechanical exfoliating ingredient and a chemical exfoliating ingredient lies in their specific methods of action on the skin. Mechanical exfoliants work through physical action, using small, rough particles or substances, which help to remove dead skin cells through gentle to firm scrubbing motions. This type of exfoliation doesn't alter the skin's chemical balance but effectively reduces the microbial load on the skin or tissue. Examples include microbeads, sugar or salt granules, and even finely ground nut shells.
In contrast, chemical exfoliants use mild acids or enzymes to loosen and dissolve dead skin cells, promoting skin renewal at a chemical level. These ingredients rely on a chemical reaction that breaks the bonds between skin cells, allowing them to detach and be washed away. Common chemical exfoliants include alpha-hydroxy acids (AHAs), beta-hydroxy acids (BHAs), and enzymes derived from fruits. Unlike mechanical exfoliation, chemical exfoliation can penetrate deeper into the skin and work without the need for physical abrasion.