A study that was published in Family Practice News (February 1, 2005:48) looked at 85 women suffering with menopausal hot flashes or night sweats. The subjects selected had at least five hot flash or night sweat episodes per day. The women were divided into two groups and for a period of three months were given either a placebo or flax  seed supplement (40 g/day). After the initial three months, they switched therapies, with the placebo group receiving the supplement and the treatment group receiving the placebo for a second three months. Flax seed supplementation resulted in a 38% reduction in the median number of hot flashes when compared to placebo.

An increase in lignan markers like enerodiol, enterolactone, and others. Lignans are phytoestrogens found in flax seed. In this study, the flax seed supplementation reduced follicle stimulating hormone and apolipoprotein A1. Another study, published in the journal Nutrition in Cancer (2001;39(1):58-65) found that supplementation with ground flax seed reduced 17 beta estradiol and estrone sulfate, and increased prolactin in the serum.