If you’re concerned with the metabolic effects of ephedrine wearing off or being less potent, I’ve seen research that with prolonged/chronic use, despite the “feelings” being non-existent or not as potent (i.e. the giddy-up), the thermogenic effects were maintained or more potent. I’d have to look into it further and get back on that for sure. I’m by no means endorsing chronic use, just throwing that point out.