You will most definetaly build tollerance to any thermogenic.
The best way to keep the effects from use in these products is to cycle them. I think that cycleing wiil vary from person to person.
If you start to loose the effects , take a week or even 2 weeks off from usage. This is what works for me. I only take thermogenics for the BUZZ before i go to the gym.
Increasing the dossage does not seem to help the effects for me.