These do work, I got this on clearance for $20 which is waay below the retail price.
It works, I've notice an increase in consistent strength but also somewhat more aggression as well.
I recommend only 1 daily since I've noticed that when I take 2, my muscles feel more stiff.
I think if you have good sleep, and can afford this, you should consider buying this especially when it's on clearence but if you are tight on money, you don't really need this and can just stick to creatine.