this is info from kilosport.com
YOHIMBINE HCL
Notes:
Type: Powder
Product Summary
Yohimbine hydrochloride, derived from Yohimbe bark, is an indole alkaloid which blocks both dopamine and a2-adrenergic receptors, while stimulating serotonergic receptors. Yohimbine-containing supplements have been marketed as sexual enhancers and for weight loss.
The effect of yohimbine on alpha2-receptors is of particular interest to those interested in weight loss. Fat cells (adipocytes) express a high level of alpha-adrenergic receptors. Alpha2-receptors, in particular, are involved in the regulation of lipolysis (breakdown of stored fat). Thus, yohimbine, by inhibiting alpha2-receptors, promotes the liberation of stored fat so that it may be used for energy (as by muscle).
Because of yohimbine's stimulatory actions on the sympathetic nervous system (SNS), it can increase blood pressure and anxiety. The mechanism of this effect is attributable to the blockade of the central and/or the presynaptic alpha2-receptors in the SNS. Yohimbine has a relatively higher affinity for alpha2- than for alpha1-adrenergic receptors.
The alpha2-receptor antagonist properties of yohimbine can increase insulin levels.
Yohimbine shoulid not be used by persons with kidney disease, those undergoing drug (e.g., opioid) withdrawal, or in combination with antidepressants. Yohimbine can elevate cortisol levels and produce a stress response involving fear and anxiety in susceptible persons.