The results of a study of the clinical effectiveness of the correction of involutional changes in the skin by the method of photodynamic therapy (PDT) with the use of a photosensitizer gel (PS), the active substance of which is the trismeglumine salt of chlorin e6, are presented. The data of fluorescence spectroscopy for monitoring the level of PS fluorescence in order to determine the optimal time of its exposure are demonstrated. The study of the optimal exposure time involved 80 patients with different skin phototypes. The study of the effectiveness of PDT involved 42 patients aged 44–68 years with signs of chrono- and photoaging. The PDT procedure was performed by irradiating the entire surface treated with the PS with a power density of 100 mW/cm2, a light dose of 120–140 J/cm2, a laser radiation wavelength of 660 nm, and a light beam area of 400–800 cm2. It was found that exposure to PS for 10–20 min gives the highest fluorescence and does not depend on the skin phototype. The clinical effect of PDT was achieved in 85.7% of patients; there were no negative subjective sensations. Moisture metrics increased on the skin of the face by 53%, reaching the control values in young healthy volunteers, on the skin of the hands - by 64%. Elastometry indicators on the skin of the face and hands increased by 19% and 16%, respectively. Thus, the PDT procedure with PS based on chlorin e6 is an effective method for correcting involutional changes in the skin, leads to a pronounced clinical effect, improves the parameters of skin moisture measurement and elastometry, and passes without undesirable local reactions. Optical coherence tomography showed an increase in collagen ordering.