Menopause is defined as the absence of menstruation for 12 months without a pathological cause and it is marked by physical fluctuations and biological changes that can impact women's quality of life. During the perimenopause and menopause transition period, women may experience a variety of changes, including menstrual cycle irregularity and climacteric symptoms. Treatment to relieve symptoms may include hormonal and non-hormonal options, such as behavioral therapies, medications and low-dose hormonal therapies. The objective of this study will be to evaluate the effect of melatonin in women with perimenopausal symptoms. This is a double-blind, placebo-controlled randomized clinical trial research, where perimenopausal women will be interviewed, who will answer questionnaires, and will use melatonin/placebo for a period of 30 days, before and after, they will have samples of blood and urine collected, which will be measured and stored in the Univates laboratory. They will also be asked about possible changes during treatment, such as mood changes, drowsiness, dizziness, headaches or allergic reactions. It is hoped that with this study, the effect of melatonin in women on climacteric symptoms during the perimenopausal period will be understood.