Dermal fillers have gained significant attention in the field of aesthetic medicine due to their ability to restore volume and correct facial wrinkles. Even though such formulations have similar compositions, they can have different microstructure and molecular characteristics, which in turn affect the biodegradation profile. This study presents the results of an investigation of the physicochemical characteristics of four dermal fillers from different manufacturers (Sculptra^®, Gana V^®, AestheFill^®, and Repart PLA^®). The molecular and supramolecular characteristics of polylactic acid (L/D isomer ratio, molecular weight, degree of crystallinity), the morphology and size of PLA microparticles were determined. Hydrolytic degradation studies in phosphate buffer revealed differences in the rate of molecular weight reduction in the polymer. The obtained data may be important for the analysis and interpretation of the results of biological studies and clinical outcomes of the PLA dermal fillers.