Hyaluronic Acid Basics and Rheology.

Hyaluronic acid (HA) is the most common dermal filler in use. It improves wrinkles and volume loss not only by filling and volumizing but also by hydrating the injected area with its water affinity. It is a naturally occurring component of skin, and there is a negligible risk of immunologic or allergic reaction with injection. It is rapidly degraded by the injection of hyaluronidase, thus creating an ideal injectable material that is low risk and reversible. Its duration of effect may be longer than expected based on bioavailability of the HA product due to collagen synthesis or fibroblast stimulation.