Petrolatum is a semi-solid mixture of hydrocarbons derived from petroleum, refined to cosmetic and pharmaceutical grades to remove impurities. From a dermatological and formulation science perspective, petrolatum is one of the most effective occlusive agents available, capable of reducing transepidermal water loss (TEWL) by up to 30 – 50% or more depending on concentration and formulation context. Its mechanism of action is strictly physical rather than biochemical: petrolatum forms a continuous, hydrophobic film over the skin surface, preventing evaporation of endogenous moisture and creating an optimal environment for barrier repair. Unlike humectants or emollients that interact with water or lipids within the stratum corneum, petrolatum functions as an inert barrier sealant, making it particularly valuable in compromised, inflamed, or severely dry skin conditions.

In skincare formulations, petrolatum is widely used in barrier-repair creams, ointments, healing balms, lip products, and dermatological treatments for xerosis, eczema-prone skin, and post-procedure recovery. Its chemical stability, resistance to oxidation, and lack of reactive functional groups contribute to exceptional shelf-life and formulation robustness. In haircare, petrolatum is employed more selectively, primarily in pomades, scalp protectants, and occlusive treatments designed to reduce moisture loss from the hair shaft and scalp. While it does not penetrate the hair fiber or provide intrinsic conditioning at the molecular level, it is effective at sealing moisture, enhancing shine, and reducing mechanical friction, particularly in textured or tightly coiled hair types when used in controlled amounts.