How much caffeine is too much?
The FDA cites 400 milligrams a day as the threshold generally not associated with negative effects in healthy adults, which lands around four cups of brewed coffee, though tolerance and sensitivity vary widely and some people feel jittery at one. Pregnancy changes the math: ACOG advises staying under 200 milligrams daily. Energy drinks complicate things by stacking caffeine with other stimulants and a lot of sugar, and mixing caffeine with alcohol is specifically discouraged because it masks how drunk you are.
The genuinely dangerous form is not coffee but concentrate. Pure powdered and liquid caffeine sold online is potent enough that a single teaspoon of powder can equal dozens of cups and has caused deaths, which is why the FDA has cracked down on bulk sales. For everyday coffee drinkers, the practical signals of too much are your own body's, insomnia, racing heart, anxiety, stomach upset, and the fix is simply cutting back, ideally tapering, since abrupt withdrawal delivers a few days of real headaches.
About 400 mg a day is the FDA safe ceiling for healthy adults, roughly four cups of coffee. Pregnancy drops it to 200. The real danger is powdered caffeine, where a teaspoon can be lethal.
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