Dietary Supplement. Yohimbe Bark Extract. The Science Behind the Size: Product: A quick-acting concentrated and guaranteed potency Yohimbe bark extract that has been standardized for Yohimbine. Result: Promotes stamina through increased blood flow. Science: Yohimbe has been used historically to improve sexual function. (These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.)