Does soy help with night sweats during perimenopause?

Soy is among the better-evidenced dietary interventions for vasomotor symptoms including night sweats during perimenopause. The effect is modest compared to hormone therapy, but the evidence supporting soy isoflavones for reducing hot flashes and night sweats is stronger than for most foods discussed in this context.

What causes night sweats during perimenopause:

Night sweats are the nocturnal form of vasomotor symptoms. As estrogen declines, the hypothalamus becomes hypersensitive to minor fluctuations in core body temperature, triggering sudden dilation of blood vessels and sweating in response to changes that would not register in a higher-estrogen environment. Inflammatory signaling appears to lower this threshold further, meaning women with higher systemic inflammation tend to experience more frequent and intense vasomotor events.

How soy isoflavones work:

Soy contains isoflavones, primarily genistein, daidzein, and glycitein. These compounds are phytoestrogens that bind preferentially to estrogen receptor beta (ER-beta). ER-beta is expressed in the hypothalamus, the region that controls thermoregulation. By providing weak estrogenic activity at hypothalamic receptors, soy isoflavones may partially stabilize the thermoregulatory threshold that estrogen normally maintains, reducing the frequency and intensity of vasomotor responses including night sweats.

What the research shows:

A meta-analysis by Taku et al. (2012) reviewed randomized controlled trials and found that soy isoflavones reduced hot flash frequency by approximately 21 percent and meaningfully reduced severity compared to placebo. Night sweats follow the same vasomotor mechanism as hot flashes. Messina (2014) confirmed in a comprehensive review that the evidence for isoflavones reducing vasomotor symptoms is consistent across multiple well-designed trials. These are real findings, not marginal associations.

Equol producers respond better:

Daidzein, one of soy's key isoflavones, is converted in the gut to equol by specific bacterial strains. Equol has substantially more potent estrogenic activity than daidzein itself and drives a significant portion of soy's vasomotor benefit. Approximately 30 to 50 percent of Western women are equol producers. This biological difference helps explain why some women experience meaningful reductions in night sweats from soy while others notice little change despite consistent intake. There is currently no widely available clinical test for equol-producer status.

Dietary soy versus isoflavone supplements:

Both whole soy foods and standardized isoflavone supplements have been tested in clinical trials. Whole soy foods, including edamame, tofu, tempeh, and soy milk, provide isoflavones alongside a broader package of nutrients including complete protein, B vitamins, and minerals. Fermented soy foods such as tempeh and miso have better digestive tolerability and potentially enhanced isoflavone bioavailability due to fermentation. For women who do not tolerate soy foods well digestively, standardized isoflavone supplements are an alternative worth discussing with a provider.

If you have or have had a hormone-sensitive condition such as breast cancer, endometriosis, or uterine fibroids, discuss soy with your healthcare provider before making significant changes to your intake. Eden (2012) reviewed soy and breast cancer risk and found no evidence of increased risk from moderate dietary intake, but women with prior or active hormone-sensitive conditions should receive individualized guidance.

Practical guidance:

Aim for 1 to 2 servings of soy foods daily to reach isoflavone intakes consistent with trials showing benefit. One serving is approximately half a cup of edamame, 100 grams of firm tofu, or a cup of soy milk. Consistency over weeks matters more than single-meal intake, as isoflavone effects accumulate over time.

Tracking with PeriPlan:

PeriPlan lets you log night sweat frequency, intensity, and sleep quality alongside dietary choices and cycle phase. Tracking over 6 to 8 weeks of consistent soy intake gives you meaningful data on whether soy is helping your specific pattern. Because response depends partly on equol-producer status, your own tracked experience is the best measure of benefit.

When to see a doctor:

If night sweats are severe enough to require changing clothes or bedding multiple times per night, are significantly disrupting sleep, or are not improving with dietary and lifestyle changes, speak with your healthcare provider. Night sweats that are accompanied by fever, chills, unexplained weight loss, or swollen lymph nodes need prompt evaluation to rule out non-hormonal causes. Hormone therapy remains the most effective evidence-based treatment for severe vasomotor symptoms and may be appropriate for you.

This content is for informational purposes only and does not replace medical advice. Always consult your healthcare provider about your specific situation.