Dark circles under the eyes have several causes, including shadowing from puffiness above, pigment in the skin and vascularity below the skin surface. Glycolic peels are safe at both 20 and 30% in trained hands, but typically improve skin texture and won't do much for most dark circles. Better to have someone assess your eyes to see why you have dark circles and treat them appropriately.
Without before pictures or seeing you in person and examining your skin, it is impossible to give you specific advice. Such low strength peels are likely not going to make much of a difference.