Hyaluronic acid (HA) dermal fillers have become very popular agents for facial rejuvenation. There are a number of HA fillers available on the market with continuous evolution of products and product ranges, technology and injection strategies and approaches. The choice of product can become confusing for practitioners with so many different brands, characteristics and strongly marketed unique selling points of each product. In this paper, basic characteristics and rheology of the HA fillers are discussed to aid selection of appropriate products for the correct indications, taking into consideration patient factors.
HA is found in nearly all biological fluids and tissues, including synovial fluid and extracellular matrix. Both vertebrates and the capsule of some bacteria contain HA.1 It has a high molecular mass and has unique biological, viscoelastic and rheological properties, making…