I added a cap of Avant Labs H.E.A.T. stack to my normal Levi. RL dosage. At first, it seemed great but about an hour later I was super jittery and my heart would race even with moderate physical activity. Following that, I got a terrible stomach ache. I feel better now; it was probably too much yohimbine in the form of its analogs (i.e. 11-hydroxy & alpha yohimbine).