Caffeine
Also known as 1,3,7-trimethylxanthine
Caffeine is a natural stimulant found in coffee, tea, cacao, and many soft and energy drinks. It boosts alertness and can improve exercise performance, but too much causes jitters, insomnia, and a racing heart. The FDA cites up to 400 mg/day as generally safe for healthy adults, and health authorities advise pregnant people to limit intake to about 200 mg/day.
Why it matters
What it does in your body
- Increases alertness and reduces fatigue
- Can improve endurance and exercise performance
- Stimulates the central nervous system
- Is not an essential nutrient
By age, sex, and life stage
How much you need
This is a safety limit, not a requirement. The FDA cites up to 400 mg/day, roughly two to three 12-ounce cups of coffee, as an amount not generally associated with harmful effects in healthy adults. Pregnant and breastfeeding people are advised to limit intake to about 200 mg/day. Adolescents should have much less, around 100 mg/day or under, and caffeine is not recommended for children.
Full reference table
| Life stage | Male | Female |
|---|---|---|
| Healthy adults | up to 400 mg | up to 400 mg |
| Pregnancy and lactation | n/a | about 200 mg |
| Adolescents | 100 mg or less | 100 mg or less |
| Children | not recommended | not recommended |
Values in milligrams/day. AI marks an Adequate Intake, used when there is not enough evidence for a formal recommendation.
What moves the number
What changes your needs
Body weight and tolerance
Smaller people and those not used to caffeine feel stronger effects at lower doses.
Pregnancy
Caffeine crosses the placenta and is cleared more slowly, so a 200 mg/day limit is advised.
Medications and health
Certain medicines, anxiety, and heart rhythm conditions can lower a safe personal limit.
Timing
Caffeine has a long half-life, so afternoon and evening intake can disrupt sleep.
Running low
Signs you might not get enough
Most at risk: There is no deficiency state. Withdrawal symptoms can occur in habitual users who suddenly stop.
Too much
Can you get too much?
Effects add up across coffee, tea, soda, energy drinks, and supplements. Highly concentrated powdered or liquid caffeine is dangerous and easy to overdose on.
Where to get it
Best food sources
The bottom line
Up to 400 mg/day is safe for most healthy adults, about two to three cups of coffee. Halve that in pregnancy, and watch how caffeine from all sources affects your sleep.
Track caffeine automatically
Caffeine is one of the 92 nutrients Vora reads from a photo of your meal, so you can see where you stand without weighing or logging by hand.
Sources and method
The recommended intakes, upper limits, and food-source amounts on this page come from the primary references below. Numbers were checked against the current NIH Office of Dietary Supplements fact sheets and the Institute of Medicine (now the National Academies) Dietary Reference Intakes.
- U.S. Food and Drug Administration, guidance on caffeine intake
- American College of Obstetricians and Gynecologists
This page is for general education, not medical advice. Reference intakes are population averages for healthy people and do not replace guidance from your doctor or a registered dietitian, especially if you are pregnant, managing a health condition, or considering supplements.