Bulbine Natalensis is an herb from Southern and South Eastern Africa that has traditionally been used as an aphrodisiac as well as some other beneficial properties. Due to its influences on cognition and sexuality, it is currently being investigated for its effects on testosterone.
Three separate rat studies looking at serum testosterone levels note significant increases in circulating testosterone, and one study noted a decrease in estrogen levels as well. That being said, adverse effects have been reported on both the liver and kidneys with the exact same dosages seen to increase testosterone.
