When your skin is moist, it becomes more receptive to absorbing hydrating products allowing it to penetrate deeper. The presence of water on your skin also softens its outer layer, facilitating an even spread of the moisturizer.
Applying hydrating products (certain toners, essence, certain serums, skin mists, & moisturizers) to damp skin offers a dual advantage—it not only helps lock in existing moisture through the 'occlusion effect' but also forms a protective barrier that prevents water from evaporating. This ensures prolonged skin hydration.
Moreover, hydrating wet skin enhances the product's effectiveness. The moisture enables deeper penetration, providing enhanced hydration and nourishment. The added benefit is that the water content in the skin aids in smoothing its surface, promoting an even application of the products.
Conversely, applying hydrating products to dry skin proves less effective. Dry skin tends to repel rather than absorb the product, leading to a surface-level application. This not only compromises the products absorption but can also exacerbate skin sensitivity and irritation. Dry skin signals a compromised skin barrier, hindering optimal moisture retention. Picture it like water on a dry sponge—applying moisturizer to dry skin is akin to placing water on the surface rather than ensuring absorption.
(Some products, including but not limited to retinoids, other medicated formulations, and vitamin C, are best avoided on wet skin).