Vitamin B is fine, but it produces energy in the body when it's using it properly. Also, your urine will appear to be a bright yellow. This means that your body is excreting the B vitamins and you probably don't need it.
This can be true.
But for me, it's actually best that I DO take vitamin B's before bed. I think the two I take are B3 and B6. I take calcium, too, but that's because even as a kid I wouldn't drink a drop of milk. Plus if I'm not careful I'll get leg cramps galore at night. Super painful.
But as far as vitamin B's giving you energy, here's my experience with them:
I used to have what I'm going to call a "Stressed-out brain." When you have that, you're on edge, you can't always think the clearest, and all you know is something isn't right, but you don't know what it is or how to fix it and you're stressed to the max for little to no reason. You're either going to under-eat or overeat (Since for me, a couple months earlier, I got over the swine flu, and didn't eat anything beyond saltines for a good 2 or 2 and a half weeks. It made me borderline anorexic, because even after I got over it, I didn't wanna eat barely anything.).
When I went to my homeopathic doctor for the first time, I was a mess, and he said I had what I call a stressed-out brain, and for lack of better words it weakened my brain. I was one of the worst cases he saw of it, too. I went on numerous vitamin and herb supplements, I went gluten-free, and my family says after a day or two they saw a difference, though I didn't notice it as much until a week or two later.
I did have more energy during the day when I took them, because the chemicals in my body weren't so imbalanced. Vitamin B's just didn't give me energy for some reason. (Funny story: one time, before I went dairy free, I bought a Starbucks energy thing, which had bunches of vitamin B's, plus caffeine on top. I think I drank all of it, and everyone said I was calmer than I was before! haha)
So just a small note everyone, different vitamins will do different things to each and every one of us. And vitamins aren't just to help with weight-loss or acne or to get you better hair and nails. They're to help balance and heal you. So if you can, I suggest that you either go to a homeopathic doctor or a nutritionist who believes in holistic medicine before taking things you think you need to take.