Isoflavones, particularly those derived from soy, are phytoestrogens—plant-based compounds structurally similar to human estrogen. Their use in menopause is primarily supported by scientific studies, although the strength of evidence is moderate. Isoflavones are thought to alleviate menopausal symptoms such as hot flashes and night sweats by binding to estrogen receptors and exerting weak estrogen-like effects.

Multiple randomized, placebo-controlled trials and meta-analyses have investigated the efficacy of isoflavones for menopausal symptom relief. A 2021 Cochrane review found that soy isoflavones may reduce the frequency and severity of hot flashes compared to placebo, but the effect size is modest and there is considerable variation between studies. Some studies report a reduction in hot flash frequency by about 1-2 episodes per day. However, not all trials demonstrate significant benefits, and heterogeneity in study design and isoflavone formulations contributes to inconsistencies.

Safety profiles for isoflavones are generally favorable, with few adverse effects reported in short-term studies. While isoflavones are widely used as an alternative to hormone replacement therapy (HRT), major guidelines still consider the evidence insufficient for a strong recommendation. Overall, isoflavones are scientifically validated as a possible, but not definitively proven, option for managing mild menopausal symptoms.