Novel sulfhydryl group-containing amides and disulfide group-containing bis-amides useful for treating or preventing an abnormal biological condition or a disease, and/or improving the texture or appearance of the skin, as well as compositions containing amides and bis-amides and methods for their use are described. Such types of abnormal biological conditions or diseases include skin atrophy, i.e., the thinning and/or general degradation of the dermis often characterized by a decrease in collagen and/or elastin as well as decreased number, size and doubling potential of fibroblast cells, and other maladies including, but are not limited to dry skin, severe dry skin, dandruff, acne, keratoses, psoriasis, eczema, skin flakiness, pruritus, age spots, lentigines, melasmas, wrinkles, warts, blemished skin, hyperpigmented skin, hyperkeratotic skin, inflammatory dermatoses, age-related skin changes and skin in need of cleansers.