Study: Soy Germ Extract Supplementation Reduces Hot Flashes

Fact checked

By Menopause Now Editorial Team | Updated: Feb 23, 2021


Soy is perhaps one of the most recognizable herbs among menopausal women. Its richness in isoflavones - such as daidzein and genistein - is believed to be behind soy's health benefits, including relieving symptoms of hormonal imbalance.1

However, not all of the alleged properties of various isoflavones have been scientifically confirmed. This particular trial took a closer look at the effects of daidzein-rich soy germ extract on menopausal hot flashes.

Study: Soy germ extract supplementation reduces hot flashes

Study Design

This parallel clinical trial was conducted at several health centers in three different countries: Austria, Romania, and Germany. It involved 180 women, aged 45 to 70, who were struggling with hot flashes.

The study began with all women documenting their hot flash episodes in a diary for two consecutive weeks. Once patterns were recorded, phase I of the trial started, in which women received one capsule per day for 12 weeks:

  • The intervention group received capsules containing 250 mg of soy germ dry extract, 100 mg of isoflavones (including isoflavone aglycones, genistein, daidzein, and glycitein), and micronutrients.

  • The placebo capsules contained microcrystalline cellulose.

After 12 weeks, phase II of the trial began, during which all women received soy capsules for another 12 weeks.

Throughout the study, women underwent check-up visits to assess compliance, potential adverse reactions, the number of hot flashes, and the severity of menopause symptoms (using the Greene Climacteric Scale, GCS).

Study Findings

After phase I of the trial, the average number of hot flash episodes significantly decreased from 8.2 to 4.7 (43.3%) in the intervention group and from 8.4 to 5.8 (30.8%) in the placebo group.

After phase II of the trial, the mean number of hot flash episodes further decreased to 2.65 and 2.7 in the intervention and placebo group, respectively. This means that the overall number of hot flashes was reduced by about 68% in comparison to pre-treatment patterns.

In women taking soy, the severity of hot flashes and night sweats decreased by 71% and 78%, respectively, in contrast to 24% reductions in the placebo group.

After soy treatment, there were also significant improvements in other menopause symptoms, such as libido, sleep problems, concentration, fatigue, and others.

What Does It Mean?

As can be seen by the findings, soy germ extract is effective for reducing hot flashes' frequency and severity. Although the first benefits were observed after the initial 12 weeks of supplementation, soy's full effects were better expressed in the subsequent 12-week phase.

Researchers noted that the most beneficial effects were registered in women who struggled with frequent and intense hot flashes per day as opposed to those who had mild or infrequent episodes.

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