If I drink a medium Dunkin' Donuts caffeinated coffee (I did today), say at 2:00 PM, and I want to go to bed at 11:00 PM, although it's a difference of nine hours I can't fall asleep. In fact, I won't even get tired until 3:00 AM which is why I'm posting this now, at 2:00 AM. I'm a 23 year old male and I do drink coffee regularly, but 13 hours of a caffeine buzz seems f***king outrageous.

I've done the experiment and have refrained from drinking coffee one day, and I could fall asleep at a normal time. Clearly, the coffee is the culprit, but and this hasn't been a problem until six or seven months ago. I could drink coffee at 7:00 PM and fall asleep on time.

It could be Dunkin' Donuts's blend, specifically. Does anyone else have this annoying problem?

Yes. I find it matters how much coffee I drank in the morning. But by mid afternoon, I have to be really careful about how much I drink if any or I can't sleep. If I had hardly any in the morning, I can drink some. Yeah. 2 pm, 3pm. Annoying isn't it? :)

I did not have this problem in my 20s. It started when I was about 30.