I don't think it's your tolerance to stims. Reign is designed to give a smooth long lasting energy; no jitters, no anxiety. Everyone (myself included) I've read describes it the same: no real stimulant kick, you just realise 30-45 min. after drinking it that "hell yeah, I'm ready to lift some heavy ****!". The energy and focus are out of this world for me! Mind-muscle-connection!
I think too many people are used to being hit over the head with a sledge hammer, in terms of their stimulant use (or should I say reliance). Reign, in my opinion, is more subtle or refined than that with its complimentary ingredients, but far more effective--and functional--than any other stimulant blend I've ever used (and I'm 56, so I've tried a few "stimulants" over the years).
Crowbar