Moisturizers are substances designed to improve and maintain the skin barrier. They could include active ingredients that minimize dehydration, photoprotect, and provide antioxidant properties. Moisturizers are based on occlusive substances such as petrolatum and dimethicone, and humectant substances, such as glycerin, with a variety of sunscreens and botanicals for added functionality. Moisturizers prevent and treat dry skin, protect sensitive skin, improve skin tone and texture. Also, moisturizers can serve as important adjunctive therapeutic modalities for patients with various dermatologic disorders, including acne vulgaris, rosacea, retinoid-induced irritant dermatitis, atopic dermatitis, psoriasis, and the skin dryness that appears to occur with intrinsic and extrinsic aging. Therapeutic moisturizers, defined as those proven in clinical trials to be both compatible with topical therapies and biocompatible with the skin, not only improve the signs and symptoms of dry skin but also, as research has demonstrated, help maintain hydration and overall integrity of the stratum corneum. The type of humectants and emollients contained in a therapeutic moisturizer can affect the overall tolerability of the formulation. Dermatologists should recommend therapeutic moisturizers that are noncomedogenic, devoid of irritant ingredients, and compatible with many therapeutic regimens. But some factors have to be considered when assessing the safety of a moisturizer. We should consider harmful effects including allergenicity, irritation and carcinogenesis.