How much caffeine is too much? What the guidelines say
For most healthy adults, a few cups a day is fine. Where the line sits, and why it moves for some people.
Caffeine is the world’s most widely used stimulant, and for most people it is perfectly safe in sensible amounts. The question is what “sensible” means.
The commonly cited limit
Health agencies such as the US Food and Drug Administration say that up to 400 milligrams a day is not generally associated with negative effects for healthy adults. That is roughly:
- 3 to 4 cups of regular brewed coffee,
- 8 cups of black tea, or
- 10 cans of cola.
Caffeine content varies a lot, though. A small cup of drip coffee can contain far less than a large cup from a coffee shop, so the cup count is only a rough guide.
Why your limit may be lower
People respond to caffeine differently, depending on genetics, body size, medication and how often they drink it. You may need to cut back if you notice:
- trouble falling asleep or staying asleep,
- jitteriness, a racing heart or anxiety,
- stomach upset or headaches.
Pregnant people are usually advised to limit intake to around 200 milligrams a day, and anyone with a heart condition, an anxiety disorder or who takes certain medicines should check with a doctor.
Protect your sleep
Caffeine has a half-life of roughly five to six hours, which means that coffee at 3 p.m. can still be affecting you at bedtime. A simple rule is to stop caffeine six to eight hours before you plan to sleep.
Watch for hidden sources
Energy drinks, pre-workout powders, some painkillers and chocolate also contain caffeine, and they can push you over the line without you noticing. Check labels, especially on supplements.
If you want to cut down, do it gradually over a couple of weeks. Stopping suddenly can cause headaches and tiredness for a few days.
This article is general information, not medical advice.
