I have only been using these for a week, so a little early to say how effective they are.

I did get tingles (in my ears!) like people said, but I found that this gave me a boost and I was able to lift heavier and felt stronger. This wasn't due to the placebo affect either as once I was in the gym I didn't think about it.

Gives a nice buzz, got the tingling feeling everyone describes and I can honestly say that I feel it's more helpful than an unwanted side effect! Not exactly what I was looking for but nevertheless a good product! I find them difficult to swallow but that's probably just me and hasn't effected my rating, just something for people to consider

After reading previous reviews, I can happily agree with the positive feedback. Will be ordering again!!

I was recommended this by my coach. I haven't had any negative side effects and am hoping it will help me with a marathon I'm running in 2 weeks and then with bodybuilding.