Dosage & safety
How much caffeine is too much?
There are two numbers worth knowing, and they come from the same place: the European Food Safety Authority's 2015 review of the evidence on caffeine. 400mg spread across a day, and 200mg in any single dose, are not associated with safety concerns for healthy adults.
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- ZOMBIE editorial
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- 7 min read
The two thresholds
EFSA's opinion is the reference most UK and European labelling works from. It concluded that for the general healthy adult population, habitual intakes up to 400mg per day do not raise safety concerns, and that single doses up to 200mg are similarly fine.
Both numbers matter, and people usually only remember the first. You can stay under 400mg for the day and still take an unwise 300mg in one hit before a workout.
What 400mg looks like
Caffeine content varies enormously — a filter coffee from one shop can carry twice what another serves. These are the commonly used reference figures rather than a measurement of any specific product.
| Source | Typical caffeine | To reach 400mg |
|---|---|---|
| Filter coffee, 1 mug | 95mg | About 4 mugs |
| Instant coffee, 1 mug | 60mg | About 7 mugs |
| Espresso, single shot | 63mg | About 6 shots |
| Black tea, 1 mug | 47mg | About 8 mugs |
| Energy drink, 250ml | 80mg | 5 cans |
| Cola, 330ml | 32mg | 12 cans |
| ZOMBIE pouch, 100mg | 100mg | 4 pouches |
| ZOMBIE pouch, 50mg | 50mg | 8 pouches |
The groups the numbers do not cover
The 400mg figure is for healthy adults. Several groups have different limits, and one has none at all:
- Pregnancy and breastfeeding: the NHS advises 200mg a day maximum. A single 150mg pouch is three-quarters of that.
- Under 18s: no concentrated caffeine product in this category is intended for children or teenagers, ours included.
- People with heart arrhythmias, anxiety disorders, or on medications that interact with caffeine — including some antibiotics, antidepressants and asthma medication. Ask a pharmacist.
- Anyone who metabolises caffeine slowly. This is largely genetic, varies several-fold between individuals, and the practical test is whether an afternoon coffee wrecks your sleep.
The signs you have gone past your own limit
Your personal ceiling can sit well below the population figure, and your body tells you where it is before any guideline does. The usual sequence is a racing or fluttering heartbeat, hands that will not sit still, a hot restless feeling that is not quite anxiety, and then — several hours later — an inability to get to sleep despite being tired.
If you hit that, the answer is not to power through. Stop for the day, drink water, and drop your next dose by half. Caffeine tolerance builds over about a week of consistent intake and unwinds over a similar period.
Counting it properly
The reason we print the milligrams on the front of every tin, and total the tin on every product page, is that this arithmetic is only possible if the numbers are visible. A cup of coffee does not come with a label. A pouch does.
That is genuinely the strongest argument for a measured format over a brewed one: not that it is better for you, but that you can count it.
Sources
- EFSA Scientific Opinion on the safety of caffeine (2015)
- NHS — Foods to avoid in pregnancy
- Food Standards Agency — Food supplements containing caffeine
This guide is general information about caffeine, not medical advice. If you are pregnant, breastfeeding, under 18, taking medication or living with a heart or anxiety condition, speak to a pharmacist or GP before using concentrated caffeine products.