TCA is a non-toxic chemical (trichloracetic acid), which has been used to perform skin peels for over 20 years. It is a relative of vinegar (acetic acid.) When TCA is applied to the skin, it causes the top layers of cells to dry up and peel off over a period of several days to one week. When the old skin is peeled off, it exposes a new layer of undamaged skin, which has a smoother texture and more even color. Some clinicians, in fact, still prefer TCA peels for treating sun damage or melasma, usually in combination with other in clinic treatments. TCA peels are most commonly used to reduce brown spots and age spots, to improve the texture of leathery, sun damaged skin and impart more glow, to improve melasma, to treat some types of acne and to reduce fine lines.