Caffeine: what it is and how much people take
Caffeine is a stimulant found in coffee, tea, energy drinks and many pre-workout supplements. Studies have looked at endurance and long, stop-start exercise when taken before training. For adults, the FDA's figure of 400 milligrams a day for healthy adults is the usual ceiling. Taking about 1,200 milligrams quickly can cause seizures, and pure caffeine powder makes that easy to reach.
General information, not medical advice. Check with a doctor or pharmacist before taking a supplement, especially if you are pregnant or breastfeeding, take any medicine, or are under 18.
How much people take
| What studies looked at | Studies have looked at endurance and long, stop-start exercise when taken before training. |
|---|---|
| Daily ceiling | The FDA's figure of 400 milligrams a day for healthy adults. |
Cautions and interactions
- Taking about 1,200 milligrams quickly can cause seizures, and pure caffeine powder makes that easy to reach.
- People who are pregnant, trying to conceive or breastfeeding should ask their clinician.
Dose questions
Quick answers
- What is caffeine?
- Caffeine is a stimulant found in coffee, tea, energy drinks and many pre-workout supplements.
- What has caffeine been studied for?
- Studies have looked at endurance and long, stop-start exercise when taken before training.
- How much caffeine is too much?
- For adults, the FDA's figure of 400 milligrams a day for healthy adults is the usual ceiling.
- Is caffeine safe?
- Taking about 1,200 milligrams quickly can cause seizures, and pure caffeine powder makes that easy to reach. People who are pregnant, trying to conceive or breastfeeding should ask their clinician.
Sources
- US Food and Drug Administration
https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much
Ask Supplement Check yourself
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In Claude or any app that takes MCP connectors, add https://goodturn-mcp.pages.dev/supplementcheck/mcp and ask: “Is 400 mg of caffeine a day too much?”