To evaluate the efficacy of mexidol and necessity of using it in patients with endocrine polyneuropathies caused by primary hypothyroidism (PPHT). MATERIALS AND METHODS; We have examined 51 patients with confirmed diagnosis of PPHT and assessed their neurological status and indicators of metabolic homeostasis before and after treatment. Electroneuromyography (ENMG) was performed to assess the status of the peripheral nervous system.The results indicate the presence of endocrine disorders of obligate metabolic homeostasis in patients with polyneuropathies. Antioxidants, in particular, mexidol, in a complex with other drugs can be used in the treatment of these disorders. Worsening of ENMG-parameters, demonstrating a trend towards the normalization in response to treatment antioxidants, are characteristics of this pathology.The efficacy of mexidol in patients with PPHT has been confirmed.