It will keep most people awake. Keep in mind Thermorexin lasts 8 hours as opposed to ECA's 3-4. Thermorexin is not formulated to make you feel like ECA. The wired high of ECA was something we looked to avoid. That's why it's ephedra free. I don't know your history of thermo use so I can't say how well you'd tolerate the two together.