Niacinamide, which is vitamin B3, will make you very sleepy. I have trouble getting to sleep due to menopause. I take 1000 mg of nicacinamide 1 hour before bed with about two small bites of food. Don't take regular niacin as it produces a flush to your skin and has other side effects. Niacinamide does NOT have these side effects or make you flush. It might be better to start at 1 pill which is 500 mg. One side effect is it may lower your cholesterol.