Sounds like you're getting that stuff at a bulk price. Let me guess kilosports or beyond a century, right?
I have heard so much contradicting info on this supplement as I'm sure you have too.
I followed the advice of a good friend (and self-proclaimed guru)who used it. I took just 4 grams 15-20 minutes before cardio workouts only. I definitely noticed an increase in stamina and was sweatin my ass off.
Okay, here's why you take it when you do:
Pyruvate is supposed to kick in the kreb's cycle or when your body switches from burning carbs to fat. It is what your body produces naturally to kick this cycle into gear. By supplementing pyruvate before hand, you trick the body into doing this sooner.
Now I'm guessing the fat burning starts as soon as your body is at least warmed up, usually 5 minutes as opposed to 20-25 minutes without supplementing the pyruvate.
Since your body is sparing glycogen to burn fat, you will notice a huge increase in stamina.
Now I know a lot of people might flame me for this post. I've seen it posted as the most worthless supplement in that thread on this board. Muscle Media named it the biggest supplement scam of the year (at least that's what a friend told me, I don't read that crap).
But from my experience it works and there was definitely no placebo effect. I heard how this supplement was crap and tried it expecting nothing.
Unless your really active all day, just take it before your workouts, cardio or lifting. Otherwise you're wasting it.
And one last thing. The potassium is the best version. It also comes in sodium, calcium and creatine form (the acid has to bonded with some mineral or it will burn a hole in your stomach). Most weightlifters get enough calcium and sodium but most likely could use more potassium, that is why I recommend this. I'm way too skeptical on the claims made by the creatine version.