I ditched all.of.the stimulant type preworkouts other than a couple tablespoons of instant coffee in with my shake or occasionally a little.suspension. True Nutrition's cafe mocha flavor mixes really well with the instant coffee flavor. 
Like you, I got immune to the stuff and basically all it did was run up my blood pressure and screw up my much needed sleep.
There are 3 loves in my life: my wife, my English mastiffs, and my weightlifting....Man, my wife gets really pissed when I get the 3 confused...
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