As little as 15 - 20 mg of yohimbine orally, split over 3 dosages, can be effective provided you time your dosages to take advantage of low insulin levels. 20 - 30 mg/day is probably the optimum dose for most folks. IMHO, once you exceed 50 or 60 mg/day orally, the law of diminishing returns kicks in relative to the potential negative effects on the cardiovascular system.