Objective: to determine the content of melatonin and indicators of antihypoxic resistance, the state of antioxidant protection according to the determination of the level of lactate, pyruvate and indicators of the glutathione system (glutathione reductase and glutathione peroxidase) in patients with cystic transformation of the pineal gland (CSG).Materials and methods: during the period from January 2015 to December 2016, 5930 patients were examined, including 300 people with cystic transformation of the pineal gland. 56 people were selected for laboratory examination. The age of the examined patients ranged from 25 to 43 years. Of these, 37 people with cystic transformation of the pineal gland (CSG): 20 women — people, and men — 17 people, 19 people — the control group. The data obtained were considered both in relation to the general group of patients with this disease, and in relation to the division according to gender (men, women), and the volume of HTCW (“large”, “small”).Results: in the general group of patients, an increase in the content of melatonin in saliva and blood was recorded in all portions. Against this background, the aerobic direction of metabolism prevailed, the processes of consumption and restoration of reduced glutathione increased, which indicates the activation of the mechanisms of adaptive-compensatory restructuring of the functional state of the body.Conclusion: melatonin production in patients with cystic transformation of the pineal gland is correlated with the size of the cysts, with the most pronounced production being recorded at night. In women, to a greater extent than in men, signs of stimulation of oxygen-dependent processes are found, which indicates the intensity of adaptive reactions and the elimination of toxic products in response to stress associated with the presence of cysts.