How much caffeine is too much caffeine?

To overdose on caffeine, you'd probably have to drink around 75 8oz cups of brewed coffee over the course of just a few hours. The effects vary from person to person, but that's a good estimate for a toxic dose. On the other hand, it doesn't take much caffeine at all to start experiencing negative side-effects, like heart palpitations or mood swings. A review of 200 studies suggests that a safe dose for an adult is only about 3 8oz cups.



    1. Huh…I consider myself a lightweight because after 1 mug I’m good, but two mugs and I’m too hyper to focus.  But those are 24oz mugs.

    1. I just treat myself to a couple of quadruple espressos on a Sunday now. I don’t miss my daily dose at all.

  1. I did these calculations about 9 years ago. Forgive the cut and paste.

    Caffeine LD50 (50/50 chance of killing you) is 150 mg/kg.
    Half life of 5-7 hours with extremes of 3 to 20 hours common.

    Coffee has 93 to 164 mg/5oz serving.

    I’m a big guy, 100kg, so could stand 15g before having a better than even chance of dying. Drinking 100 cups of the hard stuff at once would be a bad idea (16.4 g).

    But drink a cup of the hard stuff every 14.4 minutes and it never goes over 6.4 g (assuming a 7 hour half life).

    Now try some small woman, say 45 kg. Her limit is 6.75 gm. Might be ok or a risk, less than 50%, of dying. But if she’s on the pill, her metabolism half life is 13 hours. She hits exceed 9.3 g. Well above LD50 so probably a goner.

    Your mileage may vary.

    References: /content.htm effects.shtm

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