This question is in two parts:

  1. How many cups of coffee can one safely consume each day before first experiencing side-effects? and
  2. How many cups can one consume before it's considered harmful to one's health?

This is assuming a generally healthy human being of average weight and average height who is not taking any medication.

  • 5
    This is too broad for any of us to be able to reasonably answer, the truth is that the effects of drugs on the body is specific to each individual and their current tolerance levels. Jan 29, 2015 at 14:27
  • Some references to what current science knows about the population variabilty of caffeine tolerance/sensitivity are in this article.
    – hardmath
    Jan 29, 2015 at 15:03
  • 1
    @JoshuaAslanSmith - It's certainly the case that we can't authoritatively answer the question but it's still a reasonable question to ask. (Although I will modify the title.) Answers should link to sources. I can't edit the title. Guess I don't have enough reputation. It ought to be changed to something like: How much caffeine / day is considered to be harmful? I vote to keep open but to edit the title and some aspects of the body of the post.
    – Mayo
    Jan 29, 2015 at 15:13
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    Gray zone, broad or vague, it's still a question that's going to get asked, not just one time but several, it's a question which (likely) is of high interest to many visitors. I think a reasonable attempt to answer this question should be done.
    – deepy
    Jan 29, 2015 at 22:03
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    @therewillbecoffee as a compromise, why not document the reasons for this being too broad into an answer so future curiosity can be sated?
    – deepy
    Jan 30, 2015 at 15:23

2 Answers 2


I would recommend scanning the DSM-5 (Diagnostic and Statistical Manual, 5th edition) on caffeine and coffee addiction, as well as looking at independent studies.

Because caffeine is the most widely consumed psychoactive substance there have been many studies done on the benefits and side affects, both of which can be highly dependent on what type of person you are specifically.

Generally speaking, caffeine is considered safe for healthy adults, and you should guage your consumption based on what you think fits your lifestyle

  • Does that last paragraph mean there are no reasonable limits past which you start experiencing negative side effects or health issues? Feb 1, 2015 at 20:51
  • 1
    It means that the amount you would have to consume to be reasonably bad for you is probably beyond the amount you would feel comfortable consuming. Withdrawals are not fun though Feb 2, 2015 at 8:36

More than 90 percent of the world’s population consumes caffeine in some form on a regular basis. The stimulant drug (yes, it is considered a drug) helps a person stay awake, alert and productive. However, many people habitually go overboard, and a considerable body of research finds that can be detrimental to one’s health. Caffeine over-consumption has been linked to heart palpitations, high blood pressure, tremors, dehydration, anxiety and panic attacks. The U.S. Food and Drug Administration likewise suggests people not exceed more than 400 milligrams of caffeine each day. 400 milligrams of caffeine each day moderate’ for healthy adults

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