Ninety-three percent of New Zealand adults consume caffeine. Most of us have no idea how much we are actually getting, because caffeine does not come with a nutrition panel on a flat white.

So let us put real numbers on it.

The official New Zealand limit

Food Standards Australia New Zealand (FSANZ), the regulator that covers both countries, sets the guidance most health professionals here work from:

For a 60kg teenager, that last row works out to around 180mg — less than half the adult figure.

The number almost nobody talks about

The 400mg daily limit gets all the attention, but there is a second threshold that matters more for how you actually feel.

A single dose above roughly 210mg has been associated with adverse effects: raised blood pressure, a spike in adrenal hormones, and anxiety. That is not about your daily total. That is about how much you take in one go.

This is why two people can drink the same 400mg across a day and have completely different experiences. Spread over four separate 100mg servings, most people are fine. Taken as a single 400mg pre-workout scoop at 6am, a lot of people are not.

The dose matters. The timing of the dose matters just as much.

What 400mg actually looks like

Rough averages, because brewing method changes everything:

• Instant coffee — 60 to 80mg a cup
• Flat white or long black — 80 to 120mg, depending on whether it is one shot or two
• Black tea — 30 to 50mg a cup
• Green tea — 20 to 45mg a cup
• Standard energy drink (250ml) — around 80mg
• Large energy drink (500ml) — around 160mg
• Pre-workout — 150 to 350mg a scoop, and this is where people get caught out

Three coffees and an afternoon energy drink puts a lot of New Zealanders somewhere near 400mg without anything feeling excessive. FSANZ found up to six percent of adults exceed the recommended maximum.

Why you crash

Caffeine does not give you energy. It blocks adenosine, the molecule that builds up through the day and makes you feel sleepy. The adenosine keeps accumulating while it is blocked — you just cannot feel it.

When the caffeine clears, all of that backed-up adenosine binds at once. That is the crash. It is not a sugar problem and it is not a hydration problem. It is the bill arriving.

Caffeine has a half-life of around five hours in most adults, though it ranges from about 1.5 to 9.5 hours depending on genetics, liver enzymes, medication and whether you smoke. A 200mg coffee at 2pm still has roughly 100mg circulating at 7pm, and 50mg at midnight.

Signs you are over your line

Your personal ceiling may be well below 400mg. Common signals:

• A racing or fluttering heartbeat after a coffee
• Feeling wired but simultaneously tired
• Taking longer than usual to fall asleep, or waking at 3am
• Jaw tension, restless legs, or shaky hands
• Anxiety that appears mid-morning and has no obvious cause
• Needing caffeine to feel normal rather than to feel sharp

If several of those are familiar, the fix is usually not quitting. It is reducing the size of each individual dose and moving your last one earlier.

Practical ways to stay under the line

Set a cut-off time. Work back ten hours from your bedtime. If you sleep at 10pm, your last caffeine is around midday. That gives your body time to clear roughly three-quarters of it.

Break the dose up. Two 100mg servings four hours apart will hold your alertness more evenly than one 200mg hit, and with far less of a comedown.

Know your pre-workout. It is the single most common reason people blow past both thresholds without realising. Read the label.

Count everything. Tea, chocolate, some painkillers and some soft drinks all contribute.

The dose-control problem

Here is the practical issue with most caffeine formats: they are fixed. A can is a can. A scoop is a scoop. A double-shot flat white is not something you can take half of.

That is the reason we built Caffeine Crashers as gummies rather than a drink. Each gummy carries a known amount, so a dose is something you decide rather than something the packaging decides for you. If you want 50mg before a meeting instead of 150mg, you can actually do that.

It also means the caffeine goes with you. No can to finish before it goes flat, no fridge required.