Yohimbine is an alkaloid chemical found in yohimbe, which is derived from the bark of a West African tree. Before the advent of the PDE5 inhibitors, such as Viagra and Cialis, doctors sometimes prescribed yohimbine hydrochloride as a treatment for erectile dysfunction. Today, the drug is not widely prescribed, because it is not nearly as effective as the newer impotence drugs on the market, according to WebMD.
MayoClinic.com says scientists and medical researchers do not fully understand how yohimbine works. However, it is believed that it stimulates your body to produce more of the chemicals that support erectile function. It works for some men with impotence but has little or no effect for others.
To treat erectile dysfunction, you should take one tablet of 5.4 to 6 milligrams three times daily. This is no miracle pill that can produce an erection within an hour or less. You must take the pills for two to three weeks before seeing any results at all.