I literally had a 2 -3 pot a day coffee habit for years - and I drank good coffee - not maxwell house or folgers - that brown water masquerading as coffee --i drank good strong cuban coffee or espresso... drank it black -so theoretically there was nothing wrong with it... and it didn't affect my insomnia- infact I probably slept better caffeinated... When I gave up coffee.. I had headaches that rivalled migraines that I get... where my hair would hurt... but it doesn't last - the withdrawl headaches last about 3 days... the withdrawk crankiness - well I was cranky before... so... it never goes away