Glycolic acid is primarily used to exfoliate the skin, improve texture, and reduce hyperpigmentation, which can result in a more even skin tone. While it may help fade dark spots and sun damage, it is not typically used for the purpose of lightening or whitening the skin overall. Its effects on skin tone can vary from person to person, and it's important to use glycolic acid products as directed and to wear sunscreen when using them to prevent further skin discoloration.