Water-Based vs Oil-Based Serums for Hydration: Which One Is Right for Your Skin? (USA) Neither format automatically hydrates better. A water-based serum may supply humectants that help retain water in the outer skin layer; a facial oil mainly supplies emollients and may help limit moisture loss. The complete formula, your existing moisturizer, and how your … Continue reading Water-Based vs Oil-Based Serums for Hydration: Which One Is Right for Your Skin? (USA)