Melatonin Effects on Cardiovascular Disease Mechanisms in Midlife Women: A Randomized Clinical Trial

Inclusion Criteria * Age 40-55 years old * Female individuals with intact uterus and at least one ovary * Hypertension o Defined as a prior diagnosis of hypertension, use of antihypertensive agents, or office SBP/DBP ≥130/80 mmHg * On stable medical regimen (≥ 2 months) if taking other medications Exclusion Criteria * Prescription sleeping medications or melatonin supplementation * Pregnant or lactating * Use of tobacco, nicotine or vaping products * Night shift work * On prescription aspirin * Severe lactose intolerance * History of substance use disorder * History of suicidal ideation * History of clinically diagnosed anemia (within the past 5 years) or low hemoglobin levels (\<11.6 g/dL) within the past 12 months * Active cancer * Severe daytime sleepiness (score \>15 at the Epworth Sleepiness Scale \[ESS\])81 * Current or recent (within the past 2 months) participation in other research studies at the discretion of study investigators * Inability to provide written consent and/or to speak and read English * Any other medical, geographic, or social factor making study participation impractical