BACKGROUND Cohesion is described as the force between particles of the same substance that acts to unitethem. Contrary to rheology, there are currently no ready-made instruments designed to measure cohesion, ormethods which could be easily adapted to gels. To study and compare the possible clinical effects from thecohesive properties of a gel, it is necessary to standardize the definition and measurement of cohesion.OBJECTIVE The purpose of this study was to develop and evaluate methods for measuring cohesion.METHODS AND MATERIALS Three different methods were evaluated and compared with measures ofperceived cohesion; compression force, dispersion in water and drop weight. Two different families of fillers(Emervel and Restylane) were used for evaluating the different methods.RESULTS The compression force did not reflect the measures of perceived cohesion. The dispersion methodshowed variable results over time, had some practical issues, and is evaluated by subjective assessment. Thebest correlation to the perceived cohesion was found with the drop weight method.CONCLUSION The drop weight method which closely resembles the definition of cohesion (IUPAC) wasconsidered to be the best method for measuring cohesion.