Quick answer: For adults, Health Canada sets the maximum at 400 mg of caffeine a day, and 300 mg if you are pregnant, planning a pregnancy or breastfeeding. Most people do best well under that, spread out in small doses and stopped many hours before sleep. Too much usually shows up as jitters, a racing heart, an upset stomach or poor sleep.

Caffeine is one of the most useful tools we have for staying sharp, whether you are starting a night shift, running a long haul or getting through a day on four hours of sleep with a toddler. The goal isn't to cut it out. It's to know your numbers and use it on purpose. Here is a practical guide, with the official limits and the latest research in plain language.

How much caffeine is safe per day?

Health Canada's caffeine guidance (updated April 2025) gives three limits:

In the US, the FDA's consumer guide to caffeine uses the same 400 mg figure as an amount not generally linked to negative effects in healthy adults. Both agencies are clear that this is a ceiling, not a target. People vary a lot in how sensitive they are and how quickly they clear caffeine, and some medications and health conditions make you more sensitive.

What does 400 mg of caffeine look like?

It adds up faster than most people think. Using Health Canada's average values for an 8 oz (237 ml) cup:

So 400 mg is roughly three regular cups of brewed coffee, and a large drip coffee from a drive-through can be more than one "cup". It's also exactly 8 pieces of Sunii, which is why our label sets 8 pieces as the daily maximum and asks you to skip other caffeine on days you get there.

Don't forget the quieter sources: tea, cola, energy drinks, pre-workouts, chocolate and some over-the-counter medications all count toward your total.

What are the signs you've had too much caffeine?

The FDA lists the common ones: a fast or pounding heartbeat, jitters, anxiety, trouble sleeping, an upset stomach or nausea, and headache. If you notice these, it's a signal to cut back, and worth talking to a health professional if they keep happening.

A lot of "too much" isn't about the daily total at all. It's about taking a big amount at once. Three coffees back-to-back before a shift hits very differently than the same caffeine spread across eight hours. Smaller, measured doses are easier to manage, and that is a big part of why we built Sunii around 50 mg pieces.

How long before bed should you stop caffeine?

Longer than most of us assume. NIOSH's shift work training on caffeine notes that caffeine has a half-life of about 5 to 6 hours and can stay in your system much longer, so a coffee near the end of a night shift can still be keeping you restless when you try to sleep in the morning.

A 2023 meta-analysis of 24 caffeine and sleep studies in Sleep Medicine Reviews put numbers on it. On average, caffeine cut total sleep by about 45 minutes and reduced deep sleep. To avoid losing sleep time, the researchers suggested having a regular coffee (about 107 mg) at least 8.8 hours before bed, and a typical pre-workout (about 217 mg) at least 13.2 hours before. They describe these as starting points, not hard rules, since everyone responds differently.

The practical takeaway: the bigger the dose, the earlier you should stop. A smaller dose gives you a little more room, but caffeine is never a substitute for sleep.

How should shift workers use caffeine?

If you work nights, 12-hour rotations, early starts on site or long hours behind the wheel, timing matters even more than the total. A Cochrane review of caffeine in shift workers found caffeine may help with alertness and reduce errors, while noting the studies were small and mostly in simulated settings. Its authors saw no reason for healthy shift workers using caffeine within recommended amounts to stop.

Here is how we suggest pacing it:

1. Start small. Begin with 1 piece (50 mg) if you're sensitive to caffeine, or 2 pieces (100 mg) if you're used to it. You can always add more later; you can't take it back.
2. Front-load your shift. Take caffeine near the start and through the first half, when it helps most and has time to wear off.
3. Set a personal cut-off. Pick a time several hours before your planned sleep, earlier for bigger doses, and stick to it. On nights, that usually means nothing in the last few hours before you head home.
4. Keep a running count. Coffee from the lunchroom, an energy drink at the truck stop and a pre-workout before the gym all add up. Known doses make it easy to stay under your limit.
5. Drink water and eat real food. Caffeine doesn't replace either, and long shifts are hard enough without being dehydrated or running on empty.

For a full shift-by-shift plan, see our guide to energy gum for night shift workers.

Who should limit or avoid caffeine?

Sunii is not for children. If you are pregnant or breastfeeding, talk to your health care practitioner before using it. Check with a practitioner first if you take lithium, or if you have high blood pressure, glaucoma or an overactive bladder. Don't combine Sunii with other caffeine or stimulant products, and remember that no amount of caffeine replaces sleep. The FDA also recommends talking to a health care provider about caffeine if you take medications or have a medical condition.

How does Sunii make caffeine easier to track?

Every piece has exactly 50 mg of caffeine in total, including the caffeine from guarana, so you always know what you're taking. It's absorbed through the lining of your mouth while you chew (buccal absorption), and most people feel it within 5 to 10 minutes. That's what we mean by smoother energy, with no jitters and no crash: you take a little at a time instead of a whole travel mug at once. If you're curious how that compares with coffee, read why you feel jitters from coffee but not from energy gum.

You can see the full label on our Sunii facts page, and common questions are answered in our FAQ.

Quick facts about Sunii

• 50 mg caffeine per piece in total (including caffeine from guarana), about 1/2 cup of coffee
• Most people feel it within 5 to 10 minutes, absorbed through the lining of the mouth while chewing
• 8 pieces per pack. Serving: 1 piece if sensitive to caffeine, 2 pieces if used to it. Maximum 8 pieces (400 mg) per day; at that amount, skip other caffeine
• Per piece: caffeine 50 mg, taurine 50 mg, vitamin B6 15 mg, vitamin B5 15 mg
• Fresh mint, sugar-free, gluten-free, vegan, 0 calories per piece
• Founded in Whistler, made in Langley, BC, Canada. Family-owned, launched September 1, 2024
• A supplemented food in Canada (Health Canada) and a dietary supplement in the US (FDA)

Try Sunii your way

If you want caffeine you can measure one piece at a time, start with our 3-pack trial for $18.99, with free shipping on every order. You can also find Sunii in stores across Canada and the US, including Circle K. Use our store locator to find one near you.

Wishing you a sunii day!
Marie, your energy gum lady

Last reviewed: November 10, 2026