Benign prostatic hyperplasia (BPH) is the pathological cellular progression of glandular proliferation associated with aging. Current available treatment options for BPH have limitations and various adverse effects. Equol is a polyphenolic/isoflavonoid molecule derived from intestinal metabolism, dairy and dietary plant sources. It has the unique characteristic to bind specifically 5α-dihydrotestosterone (5α-DHT) by sequestering 5α-DHT from the androgen receptor, thus decreasing androgen hormone actions to improve prostate health by acting as a selective androgen modulator (SAM). It also has affinity for estrogen related receptor gamma (ERR-γ) and estrogen receptor beta (ER-β) within the prostate that is known to improve male health via selective estrogen receptor modulatory (SERM) activities to decrease inflammation, cellular proliferation and carcinogenesis. We investigated the possible clinical efficacy of equol on the symptoms associated with benign prostatic hyperplasia (BPH) in this study. Materials and Methods: We performed a pilot intervention study evaluating the effects of low dose oral equol supplement (6 mg, twice a day with meals) for 4 weeks in a total of 18 men (49 - 60 years old) with moderate or severe BPH. Subjects included in the study: gave informed consent, underwent a physical examination and verified their BPH symptoms as measured by the International Prostate Symptom Scores (IPSS) and then were assigned to the moderate or severe BPH groups based upon their total IPSS index. All adverse events were reported. The primary efficacy measure was the IPSS parameters comparing baseline to 2 and 4 week IPSS indices. Blood samples were collected at the baseline and 4th week visits that served as secondary efficacy parameters that included testosterone, 5α-DHT and general blood chemistries along with cardiac and hepatic function panels. Results: Low dose equol positively improved moderate to severe BPH symptoms according to the IPSS indices. In moderately symptomatic men (n = 10) 5 out of 7 of the IPSS parameters significantly improved by 4 weeks of equol treatment. In severely symptomatic men (n = 8) all 7 of the IPSS parameters significantly improved with 4 weeks of equol treatment. There were no significant changes in androgen levels, general blood chemistries or cardiac and hepatic function parameters. Although, 5α-DHT levels declined by 21% in severely symptomatic men (from baseline vs. 4 week values). Conclusion: These findings suggest that equol may provide a well tolerated and rapid beneficial therapy for BPH that can be used alone or in combination with current pharmaceutical therapies. The beneficial clinical efficacy of equol observed in this study may be due to the multiple positive biological actions that are not present in current pharmaceutical treatments.