What are the safe caffeine limits?
The most complete review of caffeine safety comes from the European Food Safety Authority (EFSA). After assessing the evidence on heart health, blood pressure, sleep, anxiety and pregnancy, it set out these reference points for healthy people:
| Group | Single dose | Per day |
|---|---|---|
| Healthy adults | Up to 200 mg | Up to 400 mg |
| Pregnant or breastfeeding women | — | Up to 200 mg |
| Children and teens | — | About 3 mg per kg body weight |
Single doses up to 200 mg and daily intakes up to 400 mg did not raise safety concerns for healthy non-pregnant adults. EFSA also noted that 100 mg close to bedtime may affect sleep in some adults.
Source: EFSA Panel on Dietetic Products, Nutrition and Allergies (2015). EFSA Journal.Count every source, not just the obvious one
Most people only count their coffee. Caffeine also comes from tea, cola, energy drinks, chocolate and supplements. Amounts in brewed drinks vary a lot, so use these as rough guides and read labels where they exist.
| Source | Caffeine (approx.) |
|---|---|
| 1 piece of GRIT. Focus | 60 mg (exact, on the label) |
| Cup of brewed coffee | Often 60–150+ mg, depends on brew and cup |
| Cup of tea | Usually less than coffee, often 20–50 mg |
| Pre-workout, 1 scoop | Often 150–300 mg, check the label |
| Energy drink, 1 can | Check the label |
Two pieces of GRIT. Focus, the daily maximum on the pack, is 120 mg. That leaves room for your usual chai or coffee within 400 mg.
Why caffeine hits some people harder
Your liver clears caffeine mainly with an enzyme called CYP1A2, and genes affect how fast it works. Fast metabolisers clear caffeine quickly; slow metabolisers keep it in their system longer.
In a study of athletes, those with the fast-metabolising CYP1A2 genotype improved endurance performance with caffeine, while those with a slow-metabolising genotype saw no benefit or even worse performance at a moderate dose.
Source: Guest N et al. (2018). Medicine & Science in Sports & Exercise.Body size, pregnancy, some medicines and smoking also change how long caffeine lasts. If a small amount makes you shaky or keeps you awake, believe your body, not the average.
Signs you have had too much
- Jitters, shaky hands or restlessness
- A fast or pounding heartbeat
- Anxiety or irritability
- Upset stomach
- Trouble falling asleep, or light, broken sleep
If you notice these, cut back. Chest pain, fainting or a very irregular heartbeat need medical attention straight away.
Who should avoid or limit caffeine?
- Under-18s: caffeine supplements, including GRIT. Focus, are not for them.
- Pregnant or breastfeeding women: keep total caffeine within 200 mg a day, and check with your doctor.
- People with heart conditions, high blood pressure, anxiety disorders or sleep problems.
- Anyone on medication that interacts with caffeine: ask your doctor or pharmacist.
The hidden cost: sleep
Even within safe limits, caffeine late in the day can quietly reduce sleep. A controlled study found a large dose six hours before bed still cut more than an hour of sleep. Read Caffeine and Sleep for a practical caffeine curfew.
What this means for you
- Healthy adults: stay within 400 mg a day and about 200 mg at once.
- Add up every source, not just coffee.
- Listen to your body; genes make a real difference.
- Protect sleep with a cut-off time, and follow the dose on every pack.
Frequently asked questions
How much caffeine is safe per day?
For healthy adults, EFSA considers up to 400 mg a day safe, with single doses up to 200 mg. Pregnant or breastfeeding women should stay within 200 mg a day.
Is 120 mg of caffeine a lot?
No. For a healthy adult it is well under the 400 mg daily reference, roughly similar to one or two cups of coffee.
Can teenagers use caffeine gum?
Caffeine supplements, including GRIT. Focus, are not intended for anyone under 18.
Why does caffeine affect me more than my friends?
Genes, especially the CYP1A2 enzyme, plus body size, medicines and habits all change how fast you clear caffeine.
References
- EFSA Panel on Dietetic Products, Nutrition and Allergies (2015). Scientific opinion on the safety of caffeine. EFSA Journal, 13(5), 4102.
- Guest N et al. (2018). Caffeine, CYP1A2 genotype, and endurance performance in athletes. Medicine & Science in Sports & Exercise, 50(8), 1570–1578.
- Drake C et al. (2013). Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Journal of Clinical Sleep Medicine, 9(11), 1195–1200.
- Guest NS et al. (2021). International Society of Sports Nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition, 18(1), 1.
This article is for general education and is not medical advice. Talk to a doctor or registered dietitian before changing your diet or supplements, especially if you are pregnant, nursing, under 18, taking medication or have a health condition.