I find this chart hard to believe: I know a shot of espresso has less caffeine in it than a cup of drip coffee but does a grande Starbucks drip really have 550mg of caffeine while a single shot of espresso has just 35mg? Link (via Paul Boutin)
Reader comments:
Aaron says:
I saw your caffine post and it reminded me that according to the Erowid drug information site, the L.D. 50 for caffeine (the amount that is lethal for 50% of a test population) is between one and four grams. So, according to the link you posted, a single grande coffee at Starbucks is just over half of the bottom of that range. It’s also worth noting that they list anything over 400mg as a “heavy” dose.
John says:
Rule of thumb for coffee and caffeine: the darker the roast, hotter the water and faster the water goes through the coffee, the lower the caffeine. Hence, espresso is generally the lowest caffeinated (real, non-decaf) coffee drink you can get.
Also, some recent studies have shown that the caffeine in a cup of coffee can vary wildly from cup to cup, even from the same pot. Well, this last bit of info I learned recently from the interweb, so it may be bogus.
Rigel says:
LD50s are typically computed from animal models, which may or may [not] vary in their extensibility to human data.
Also, not just is that 550mg figure very likely completely wrong, but the variability in caffeine content in a cup of brewed coffee is HUGE, as shown in this paper.
Sean says:
I too question the original site but I also question the Erowid source. Using the rat LD50 data from Erowid I get:
e.g. a 150lb person 150lbs = 68.04kg
68.0388555kg * 192mg/kg of body weight = 13,063.4603mg
or about 13 grams, not 1-4.
I know this is using rats and the method of administration is not mentioned so from wikipedia:
The minimum lethal dose of caffeine ever reported is 3,200 mg, administered intravenously. The LD50 of caffeine is estimated between 13 and 19 grams for oral administration for an average adult.
So a person would have to drink over 100 cups of coffee within a small time span to reach the LD50. That reminds me of the Futurama episode “300 big boys”.