Objectives: Report the results of a study to devise the factors influencing users' perception of smoothness related to dispensing Juvéderm® formulations. Introduction: Physicians need to be aware of dermal fillers' variable rheologic and physicochemical properties to select the most appropriate product for the target outcomes and achieve optimal patient results. Since a prior study showed some variation in the forces applied to dispense Juvéderm® formulations, biometric testing was conducted to assess and quantify users' perceptions of the "smoothness" of injection. Methods: Five Juvéderm® formulations with different smoothness profiles, defined as AC, D, and B, were tested by 12 experienced professionals. Muscle effort data was collected from the key muscle groups involved in the dispensing. The force applied to the plunger was recorded using a force-sensing resistor and analyzed to determine if force deviations may impact smoothness perceptions. In addition, survey methods were used to obtain subject feedback regarding perceptions of smoothness, effort, flow control, etc. P values <.1 were considered significant for this preliminary study. Results: Significantly more effort was required to dispense the formula H24 profile AC (H24AC) compared to the other formulations (P < .1). Consistently, users rated the perceived effort to dispense higher for the H24AC, followed by the VB20AC, VB20B, VB20B+, and V17D. The plunger forces' deviation was the highest for the H24AC and the lowest for the V17D. In the user's ratings, the V17D received the highest rating for overall smoothness, followed by the VB20AC, VB20B, VB20B+, and H24AC. The standard deviation of the force applied to the plunger inversely correlated with product smoothness (R = -.96). Conclusions: Objective and subjective measurements of muscle effort, plunger force, and product smoothness showed significant differences across the tested formulations. Notwithstanding, a strong correlation between plunger force deviation measures and the perceived smoothness was found, thus demonstrating users' perceptions of smoothness can be predicted. Early estimation of perceived smoothness may help product design meet physicians’ expectations of injection experience and thereby optimize aesthetic outcomes, patient safety, and treatment satisfaction.