Reply #1: Not long at all..but now I have to look it up.

[Cannikin]

Typical drip-brewed coffee contains 100 mg per 6-ounce cup. If you are buying your coffee at Starbucks or a convenience store or drinking it at home or the office out of a mug or a commuter's cup, you are consuming it in 12-, 14- or 20-ounce containers. You can calculate the number of milligrams based on your normal serving size.

Typical brewed tea contains 70 mg per 6-ounce cup.

Typical colas (Coke, Pepsi, Mountain Dew, etc.) contain 50 mg per 12-ounce can. Things like Jolt contain 70 mg per 12-ounce can.

Typical milk chocolate contains 6 mg per ounce.

Anacin contains 32 mg per tablet. No-doz contains 100 mg per tablet. Vivarin and Dexatrim contain 200 mg per tablet.

The half-life of caffeine in your body is about 6 hours. That means that if you consume a big cup of coffee with 200 mg of caffeine in it at 3:00 PM, by 9:00 PM about 100 mg of that caffeine is still in your system.


What is Caffeine?
Caffeine is known medically as trimethylxanthine, and the chemical formula is C8H10N4O2 (see Erowid: Caffeine Chemistry for an image of the molecular structure). When isolated in pure form, caffeine is a white crystalline powder that tastes very bitter. The chief source of pure caffeine is the process of decaffeinating coffee and tea.
Medically, caffeine is useful as a cardiac stimulant and also as a mild diuretic (it increases urine production). Recreationally, it is used to provide a "boost of energy" or a feeling of heightened alertness. It's often used to stay awake longer -- college students and drivers use it to stay awake late into the night. Many people feel as though they "cannot function" in the morning without a cup of coffee to provide caffeine and the boost it gives them.

Caffeine is an addictive drug. Among its many actions, it operates using the same mechanisms that amphetamines, cocaine, and heroin use to stimulate the brain. On a spectrum, caffeine's effects are more mild than amphetamines, cocaine and heroin, but it is manipulating the same channels, and that is one of the things that gives caffeine its addictive qualities. If you feel like you cannot function without it and must consume it every day, then you are addicted to caffeine.


all that BS and I still cant find an answer to your question.