Five RCTs (400 patients) were included in the review.
Three studies were assigned a score of 5 on the Jadad scale; the other two studies were given 4 and 2 points, respectively.
The use of Trifolium pratense isoflavone supplements was associated with a non statistically significant lower rate of hot flushes per day compared with placebo (WMD -1.45, 95% CI: -2.94, 0.03, p=0.05; statistical heterogeneity: I-squared 49.5%, p=0.09).
Compared with placebo, including the higher dose of isoflavones in the analysis resulted in a larger difference (WMD -1.63, 95% CI: -2.97, -0.28, p<0.02).
One study reported no adverse effects during treatment with isoflavones; the other included studies provided no information on toxicity.