What is the difference between superficial, medium, and deep chemical peels?

As the names imply, it is related to the depth of injury produced. There are many variations and different techniques,
but the most commonly used peels and their depth of injury are listed below:

Superficial peel (stratum granulosum to superficial papillary dermis)
• Trichloroacetic acid (TCA) 10% to 30%
• α-hydroxy acid 30% to 70%
Medium peel (papillary to upper reticular dermis)
• Trichloroacetic acid 35% to 50%
• Trichloroacetic acid “combination peels” (e.g., TCA + dry ice)
Deep peel (midreticular dermis)
• Phenol peels