Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan widely distributed in connective tissues, skin, and synovial fluid. Known for its exceptional ability to retain water, it is a key molecule in maintaining skin hydration and turgor. Structurally, HA is a linear polymer composed of repeating disaccharide units of N-acetylglucosamine and glucuronic acid, contributing to its hydrophilic nature.

In dermatology and cosmetics, HA is celebrated for its role in skin moisturization and anti-aging treatments. It acts as a humectant, attracting and retaining water in the extracellular matrix, which helps to plump the skin, smooth fine lines, and enhance elasticity. Topical formulations typically use low molecular weight (LMW) HA for deeper penetration, while high molecular weight (HMW) HA provides surface hydration and barrier protection

Clinical applications of HA extend to dermal fillers, where it restores volume and addresses facial wrinkles. Its biocompatibility and ability to stimulate fibroblasts for collagen synthesis further enhance its appeal. Scientific evaluations often focus on HA’s viscoelastic properties, hydration indices, and its role in reducing transepidermal water loss (TEWL), underscoring its efficacy as a cornerstone in skincare formulations.