8-Prenylnaringenin (8-PN)

A double-blind, placebo-controlled RCT (Heyerick et al., 2006; n=67 menopausal women) found that 100 µg/day or 250 µg/day of purified 8-PN significantly reduced hot flash frequency and intensity versus placebo over 16 weeks (mean reduction ~20–27% for the 250 µg dose). A 2010 randomized clinical trial confirmed that a standardized hop extract enriched in 8-PN (Medigyn) reduced climacteric symptoms on the Kupperman Menopausal Index over 12 weeks versus placebo. Endometrial safety at 8-PN doses used in trials appears acceptable based on transvaginal ultrasound monitoring, but long-term estrogen-receptor stimulation effects require ongoing surveillance.

A randomized double-blind crossover study (n=67) using hops extract standardized to 8-PN demonstrated significant reduction in menopausal hot flush frequency and severity over 16 weeks. 8-PN demonstrates the highest estrogenic potency of any known plant compound, exceeding genistein by ~100-fold in receptor binding assays. Safety studies show no adverse effects on uterine or breast tissue in short-term (12-week) menopausal trials, though long-term safety in ER+ cancer contexts has not been adequately evaluated.