This study is aiming to evaluate changes in vasomotor symptoms in postmenopausal women treated for 4 months with Omega-3 vs Soy Isoflavones.

This is a non-inferiority study of Omega 3 versus Soy Isoflavones, being each patient its own control from the baseline.

In order to determine the difference observed in the evolution of intensity, frequency and the total number of hot flashes in 4 months in patients treated with Omega-3 vs Soy Isoflavones, is planned to include at least 100 patients, 50 per treatment arm.

It si estimated a standar deviation of 0.5%, and a 10% lost follow-up rate.

Inclusion Criteria:

• Ambulatory and can complete all study procedures, which are able to read, understand and sign an informed consent and willing to come to the center for study visits.
• Postmenopausal (≥ 1 year of amenorrhea) or 6 months or more of amenorrhea with follicle stimulating hormone (FSH) ≥ 40 IU / L.
• BMI ≥ 18 kg/m2 and ≤ 30 kg/m2
• Flushing of moderate to severe intensity.

Exclusion Criteria:

• Women with surgical menopause.
• Treatment with hormone replacement therapy (HRT) in the 3 months prior to inclusion
• Uterine bleeding after menopause with undetermined cause in the 12 months prior to screening.
• Presence or history of malignancy in the past 5 years.
• Malabsorption syndrome.
• Hype or uncontrolled hypothyroidism.
• Dyslipidemia (LDL-cholesterol> 189 mg / dl or medical criteria) requiring an specific treatment of proven effectiveness.
• Chronic renal disease.
• Uncontrolled or untreated hypertension.
• Treatment with isoflavones, tibolone, Selective Estrogen Receptors Moderators (SERM´s) in the past 3 months prior to the testing selection period.
• Hormonal treatment with androgens, estrogens, progestins, alone or combined oral, transdermal, vaginal (including promestriene) or implant, in the last 3 months prior to testing selection period.
• Patients who receive or require treatment with antidepressants or anticonvulsants
• Patients with mental illness.
• History of noncompliance with taking medication.
• Suspected or abuse of alcohol or other drugs during the 12 months preceding the selection.
• Use of any experimental drug or device within 30 days prior to the selection.
• Any other condition or finding that a judgment of the investigator may jeopardise the tral conduct according to the protocol.