Yohimbine is a selective alpha-2-adrenergic antagonist. In other words, it targets and inactivates a class of receptors in the nervous system that is responsive to the neurotransmitter norepinephrine (noradrenaline).[1] Alpha-2 receptor antagonism enhances the sympathetic nervous system release of norepinephrine, causing the stimulatory and “hyperadrenergic” effects of yohimbine.
Antagonism of alpha-2 receptors also inhibits penile smooth muscle contraction and may enhance nitric oxide-mediated smooth muscle relaxation — the combined effects of which promote erection and explain the improvement in ED symptoms after supplementing with yohimbine.[2] Yohimbine also inhibits the activity of alpha-2 receptors on fat cells — where norepinephrine normally acts to suppress fat release. Inhibition of the antilipolytic effect of norepinephrine allows more lipolysis (fat burning) to occur.[3]