Smoother focus, no jitters
80mg of caffeine with 160mg of L-theanine in every chew. The 2:1 ratio used in the research, in a chew that kicks in around 5 minutes and does not end in a crash.
48p a working day on subscription (60p one-off; a bag is 40 chews, £23.95)
Free UK delivery on every order. One bag is eight working weeks of focus.
Why two to one
Caffeine on its own makes you alert, but it also raises heart rate and makes some people twitchy and scattered. L-theanine, an amino acid found in green tea, smooths that edge. Together they have been studied since 2008 in peer-reviewed trials, and the combination improves attention, reaction time and accuracy more than caffeine alone, with less of the jittery feeling.
The ratio matters. Most of the research uses about twice as much L-theanine as caffeine. Brain Bullet is built on exactly that: 80mg caffeine, 160mg L-theanine, in every chew. Coffee gives you the caffeine with none of the theanine. Capsules give you both, but take 30 to 45 minutes and a glass of water.
- 80mg caffeine: about a cup of coffee, measured.
- 160mg L-theanine: the 2:1 ratio from the research.
- Kicks in around 5 minutes, because absorption starts in the mouth.
- 27 calories, no artificial flavours, sweeteners, colours or preservatives.
Brain Bullet versus the alternatives
| Brain Bullet chew | Coffee | Caffeine + theanine capsules | Energy drink | |
|---|---|---|---|---|
| Caffeine | 80mg, measured | 80 to 200mg, varies by cup | 100 to 200mg | 80 to 160mg |
| L-theanine | 160mg (2:1) | None | Usually 100 to 200mg | None |
| Time to kick in | Around 5 minutes | 30 to 45 minutes | 30 to 45 minutes | 30 to 45 minutes |
| The feel | Calm, steady focus | Buzz, then dip | Steady, but slow to start | Spike and crash |
| Cost per dose | 60p (48p subscribed) | £3 to £4 bought out | 30p to 60p | £1.50 to £2.50 |
| Needs | Nothing | Kettle or a queue | Water | A fridge, ideally |
Figures are typical ranges for each format. Brain Bullet kicks around three times faster than drinks or pills because the chew is absorbed partly through the mouth.
Scientifically backed, measured every time
Trusted by professionals who have to be sharp for hours, including the team behind The Diary of a CEO. Made in the UK by Performance Bullet, the Dragons' Den backed makers of Caffeine Bullet.
Two flavours, one formula
Crafted in a UK sweet factory to a traditional family recipe that is over 30 years old. Soft chews like a proper toffee, with the dose measured into every one.
Best seller
Coffee Caramel
Caramel frappe flavour. The desk-drawer replacement for your third coffee.
Mint Matcha
Fresh mint with real matcha. The one to keep by the laptop.
Save £3.91
Brain Bullet bundle
One bag of each. Sixteen working weeks of focus.
Subscribe and Save 20% is on each product page: £19.16 a bag, delivered when you choose, pause or cancel any time.
Made by athletes, for athletes
Hi, I'm David. I have run for 30 years, from 16-minute 5Ks to 2:52 marathons and backyard ultras, and spent ten of them interviewing elite athletes, coaches and sports scientists on the Bad Boy Running podcast.
Caffeine Bullet started when I dropped a caffeine tablet in the sand mid-race. Chewing caffeine turned out to absorb far faster than swallowing it, so in 2016 I made the first 100mg chew. It tasted awful. Seven flavour trials with a food scientist later, it did not. Kickstarter funded the first run in 2018 and Dragons' Den backed us in 2022.
- Editor's Choice for race nutrition, Women's Running Awards 2020 and 2022.
- Over 450,000 personal bests set on Caffeine Bullet so far.
- Crafted in a UK sweet factory to a traditional family recipe that is over 30 years old. Individually wrapped so a packet lives in any pocket.
Questions before you try it
What does L-theanine actually do?
L-theanine is an amino acid found naturally in green tea. On its own it is calming without being sedating. Paired with caffeine it takes the edge off the jitters and the dip, so the alertness feels steadier and lasts longer.
Why 2:1 and not 1:1?
Most of the published trials on caffeine and L-theanine use roughly twice as much theanine as caffeine. Brain Bullet copies that: 80mg caffeine to 160mg L-theanine. Many products use less theanine than caffeine, which is cheaper but not what was studied.
How is this different from Caffeine Bullet?
Caffeine Bullet is 100mg of caffeine for sport: a sharp kick for training and racing. Brain Bullet is 80mg caffeine plus 160mg L-theanine for work, study and anything that needs calm concentration for a few hours.
When should I take one?
Five to ten minutes before you need to concentrate. It kicks in around 5 minutes and most people feel the focus for three to four hours. Avoid it within six hours of bed.
How many a day?
One chew is a normal dose. Keep caffeine at or below 400mg a day in total, which includes coffee and tea. Not for children or during pregnancy without medical advice.
What does it taste like?
Coffee Caramel is a caramel frappe; Mint Matcha is fresh mint with matcha. Both are soft chews, 27 calories, with no artificial flavours, sweeteners, colours or preservatives. You chew and swallow; nothing to spit out.
Delivery?
Free UK delivery on every order, no minimum spend, usually 2 to 3 working days.
Give procrastination the bullet
80mg caffeine, 160mg L-theanine, five minutes to focus. From 48p a working day with free UK delivery.