Phytoestrogens are plant-derived compounds with estrogen-like activity, most commonly found in foods like soy, flaxseed, and red clover. Their use for managing hot flashes (vasomotor symptoms) in menopausal women is supported by both traditional practices—especially in East Asian cultures with soy-rich diets—and a significant body of scientific research. However, the quality and consistency of scientific evidence is mixed, leading to a moderate evidence rating.

Multiple randomized controlled trials and meta-analyses have examined the effect of phytoestrogens (primarily isoflavones from soy and red clover) on hot flashes. Some studies report a modest reduction in frequency and severity of hot flashes compared to placebo, especially in women experiencing frequent symptoms. For example, a 2016 meta-analysis in JAMA found that phytoestrogen supplements resulted in a statistically significant but clinically modest reduction in hot flash frequency. However, other well-conducted trials have shown little or no benefit, and there is considerable heterogeneity in study design, supplement formulation, and participant characteristics.

Phytoestrogens are thought to exert their effects by binding to estrogen receptors, partially compensating for declining endogenous estrogen during menopause. They are generally considered safe for short-term use, though long-term safety data is limited. Overall, while not universally effective, there is sufficient scientific evidence to support their use as an option for women seeking non-hormonal management of hot flashes, particularly when hormone therapy is contraindicated or undesired.