The molecular weight of therapeutic hyaluronan (sodium hyaluronate): how significant is it?

J Rheumatol. 1994 Feb;21(2):297-301.


Various molecular weight hyaluronic acid (HA) preparations have been injected into joints for the treatment of human and equine osteoarthritis. A therapeutic advantage has been claimed for commercial products with a molecular weight in the range found in normal synovial fluid (SF), compared to lower molecular weight products. But a correlation between molecular weight and efficacy is not borne out by an analysis of the available literature on clinical results. SF viscosity, HA concentration, HA molecular weight and rate of synthesis in joint disease. It is proposed that the beneficial effect of injected HA in joint disease may be due to pharmacological rather than to physical properties.

Publication types

  • Review

MeSH terms

  • Animals
  • Horse Diseases / drug therapy
  • Horses
  • Humans
  • Hyaluronic Acid / chemistry*
  • Hyaluronic Acid / therapeutic use*
  • Joint Diseases / drug therapy*
  • Joint Diseases / veterinary
  • Molecular Weight
  • Osteoarthritis / drug therapy
  • Osteoarthritis / veterinary
  • Synovial Fluid / drug effects
  • Synovial Fluid / physiology
  • Viscosity


  • Hyaluronic Acid