Hopefully you aren't talking about No2
Whey takes about an hour to fully digest. If you really have enough time before the gym, then I recommend a preworkout MEAL, which'll be better than a shake IMO. I wake up and lift within 40 minutes of each other, so a preworkout shake is paramount for me. However, if I have the opportunity to lift at the end of my day, then about an hour before the gym I'll eat a small meal. It won't really matter what's in it aside from protein/carbs. I like some chicken w/ rice as my preworkout meal.
Another option is to buy some BCAA's. I prefer Xtend myself. If your "supplement" beckons you to take them on an empty stomach, then I wouldn't be buying them. Lifting on an empty stomach will put you in a catabolic state when lifting faster than if you ate a preworkout meal/shake. I'm pretty sure you're talking about NO2, which is one of the MANY reasons why I don't recommend them.