Trichloroacetic acid (TCA) is a versatile peeling agent used for superficial and medium-depth peels depending on the concentration of the solution. It is a trichlorinated carbonic acid that exists in the form of hygroscopic and deliquescent crystals. It has a pKa of 0.26 and is hydrophilic. It is dissolved w/v in distilled water to create the desired concentration for chemical peeling.