There are two different receptors in the body that may play a significant role in fat loss. These include Alpha and Beta-adrenergic receptors. Caffeine normally acts on beta receptors whereas yohimbine acts on alpha receptors. When caffeine acts on beta receptors it helps increase fat burning, however with too much caffeine, the receptors may become desensitized and it doesn’t work as effectively. Although, since yohimbine acts on alpha receptors, it is a novel stimulus for fat burning.