I've used up my supply, but every time I put that stuff in my bottle I had a breakout ride. Since December I've had a powermeter to confirm that.

Now, sure, it's a sample size of 1, I've been training, it's Spring so I'd be improving anyway, lots of confounding variables.

But, I've been riding / racing since the 80's so I'm pretty familiar with training / racing sensations, and this stuff seems to make a difference. I just seem to be able to punch out noticeably more intensity of effort. Makes me think of that famous photo of Greg Lemond winning the WC against Kelly in the rain. That kind of intensity.

On the downside, it tastes horrible, doesn't really dissolve at all (just sort of clump-ily floats in the bottle) and gives a bit of stomach trouble afterward.

That said, I'm hitting the order site.