Most people have no idea what they're actually consuming. Three coffees sounds moderate. Three coffees can easily be 400mg of caffeine before noon.

What the science says

The NHS and European Food Safety Authority both cite 400mg per day as the upper safe limit for healthy adults — roughly four standard cups of filter coffee. For pregnant women, that drops to 200mg. For people with anxiety, heart conditions, or known caffeine sensitivity, the right number is often lower still.

What 400mg actually looks like

One espresso: around 75mg. A large americano from a major chain: easily 200mg. A pre-workout supplement: sometimes 300mg in a single scoop. An energy drink: 80 to 160mg per can. If you're having two large coffees and a pre-workout, you've hit the limit before lunch.

The more useful question

The official limit isn't your limit - your biology is. Variations in the CYP1A2 gene determine how quickly your body clears caffeine. Fast metabolisers process it efficiently and feel minimal effects. Slow metabolisers experience stronger, longer-lasting impact from the same dose - wired at midnight from an afternoon flat white, while the person next to them slept fine. That difference is genetic, not a willpower issue.

@coochiebygucci: "Your genetics decide how long caffeine stays in your system. If it wrecks your sleep, you're probably a slow metaboliser - and the safe limit is much lower for you personally than the official guidance suggests."

Signs the balance is off

These are the milder caffeine overdose symptoms worth paying attention to: difficulty falling asleep even when tired, waking up unrested, anxiety without obvious cause, a heart rate that feels faster than it should, or needing caffeine just to feel baseline normal. None of that is a personality flaw. It's your body signalling something worth listening to.

The straightforward fix

Caffeine's half-life is five to seven hours, which means an afternoon coffee is still active at midnight. Switching to decaf after midday removes the sleep-disruption risk without changing anything else about your routine - the taste, the ritual, the break in the day. That's what Nolo is for.

Nolo: drink it at 4pm. Sleep at 11pm. No maths required.

The Nolo Team