Proposed hyaluronic acid (HA) mechanism of action*

The precise mechanism of action of HA is unknown; however, proposed mechanisms of HA activity include:

Replaces

OA synovial fluid with higher HA concentration — improves viscosity 10

Restores

shock-absorbing, lubricating ability of depleted synovial fluid 11

Maintains

boundary layer around nociceptors, reducing pain 12,13

Endogenous HA can catalyze physiological response

The synthesis of hyaluronan within synovial joints may be influenced by the concentration and molecular weight of hyaluronan in the extracellular environment.

HYALGAN® is a viscous solution with a molecular weight (500,000-730,000 daltons) fraction of purified natural sodium hyaluronate in buffered physiological sodium chloride, having a pH of 6.8-7.5. The sodium hyaluronate is extracted from rooster combs. Hyaluronate (also known as hyaluronan or HA) is a natural complex sugar of the glycosaminoglycan family and is a long-chain polymer containing repeating disaccharide units of Na-glucuronate-N-acetylglucosamine. 14

* May not be indicative of human clinical outcomes
† Within the molecular-weight range of US-approved HAs used in the treatment of OA knee pain, it is unknown what role these physiological processes may play in clinical benefit.