Yes. Sorry if I wasn't clear on that. I have read that a lot of the melantonin we find in urine is produced between 2 and 3 am. If you pee, as many people do, sometime in the early morning (most people pee about 4 a.m.) it's helpful to drink a bit.
If you're just starting out, you don't have to drink a cup, just a swallow until you're used to it.