Hydrogels have gained significant attention as effective vehicles for transdermal applications offering significant advantages in pharmaceutical and cosmetic applications. Their unique polymeric network structure enables efficient encapsulation and controlled release of active ingredients, making them ideal for therapeutic drug delivery systems (TDDs) and topical skincare formulations. In pharmaceutical approaches, hydrogels facilitate the transdermal transport of therapeutic agents into systemic circulation, improving bioavailability and patient compliance. In cosmetics, they enhance skin hydration and support the delivery of bioactive compounds, contributing to improved product performance and user satisfaction. Among various hydrogel-forming polymers, Hyaluronic Acid (HA) stands out as the most often used polymer in this field due to its biocompatibility, moisture-retention properties, and ability to penetrate the skin. This review explores the dual role of HA-based hydrogels in pharmaceutical and cosmetic application, detailing their structural characteristics, preparation methods, and mechanisms of active ingredient loading and release. Furthermore, the review presents the details on hydrogels and how they are used as TDDs. Special attention is given to hyaluronic acid (HA) in this field, and this review discusses the properties, preparation methods, and applications of HA-based hydrogels as a delivery system, including methods of loading the actives and the releasing of these actives from them.