There is no scientific evidence supporting the notion that petroleum jelly products, such as Vaseline, can darken the skin. Products like Vaseline have no effect on skin pigmentation. The idea that it darkens skin seems to be based on observations of individuals with extremely dry skin, which reflects light differently, making it appear pale, and lighter. Hydrating and moisturizing, can effectively diminish the pale appearance, restoring its natural healthy color and radiant glow.