Most chemical peels do not thin the skin at all. They take the top layers off and allow you to produce new skin from below so the total thickness will not reduce. In fact chemical peels are made to prevent you from aging faster and maintain your youthful skin.
This is because, the skin typically sheds old, dull dead skin cells every 28 days, the process slows down with prolonged sun exposure and aging. The chemical peels cause this natural cell turnover process to speed up, helping to stimulate the growth of new collagen. It safely removes or exfoliates the top layer of dead skin allowing new, more youthful, healthy skin to show through.
However, like anything, you can definitely overdo peels or laser. Chemical peels and laser should be used as directed and under the care of a physician. The number that can be done per year largely depends on your skin type, and the type/depth of the peeling.
Always consult and follow doctors’ advice and peeling / laser will maintain a youthful skin in the long run.