Subchronic and chronic safety studies with genistein in dogs

It is concluded that the administration of genistein to dogs for a period of 4-52 weeks was well tolerated and did not result in systemic toxicity. Effects of genistein on the reproductive tract at very high doses were functional in nature and are of a type that would be expected in view of the relatively weak estrogenic activity of genistein and were considered not adverse effects. In the 4-week study, the no observed adverse effect level (NOAEL) for genistein was considered to be >500 mg/kg/day and the no observed effect level (NOEL) was considered to be 150 mg/kg/day. For the 52-week study, the NOAEL is considered to be >500 mg/kg/day and the NOEL is considered to be 50 mg/kg/day.