1
                                                        By: Arc2014 on 8/10/2020
                                                        
                                                        too jittery
                                                        
I opened capsule and threw have of powder away..i been jittery, no energy at all, just horrible feeling
                                                     
                                                
                                                    
                                                        3
                                                        By: Razor on 8/18/2016
                                                        
                                                        They work
                                                        
They work well, but there out dated compared to the new stuff
                                                     
                                                
                                                    
                                                        3
                                                        By: angie82778 on 10/26/2014
                                                        
                                                        Good in the beginning, but tolerance builds quickly
                                                        
I like Stacker 2 as a no calorie substitute for my morning coffee, but the energy giving effects wear off in about 4-6 hours. After about a month of taking them, you build a tolerance and dont really notice a difference.  They are okay for occasional energy boosts, but I would recommend green tea or something as a more consistent and effective energy source. It is cheap though, so you cant ask for much.