It isn't a drink and it isn't a pill. Here's what a growing number of UK athletes reach for before their pre-session coffee - and the science that explains why.
If you've watched someone tuck a small pouch under their top lip before training and wondered what it was, you're not alone. It's become a familiar sight in changing rooms and gym car parks: no can, no shaker, no capsule — just a discreet pouch resting against the gum while they get on with the warm-up.
It's easy to miss, which is part of the appeal. What's under the lip is usually caffeine — the most researched performance aid in sport - but taken through a route most people never think about: the lining of the mouth.
Why under the lip, and not down the hatch
The inside of your cheek and gum, the buccal mucosa, is thin and dense with blood vessels. Anything absorbed through it passes almost straight into the bloodstream, skipping the stomach and the slow "first-pass" processing that a swallowed drink or capsule has to go through first.
The time difference is the reason athletes care. Research on caffeine taken this way — mostly through caffeinated gum and mouth sprays — shows it reaching the blood in around 5 to 10 minutes, against the 45 to 60 minutes a capsule or energy drink usually needs to work through digestion. A landmark study by Kamimori and colleagues first documented this back in 2002, and the reviews since have kept landing in the same place.
For anyone who's ever downed a pre-workout, warmed up, and still felt nothing by their second set, that gap between 10 minutes and an hour is the whole game.
Why athletes found it first
This started in sport for a practical reason. Caffeine's effect on alertness and endurance is about as well-evidenced as anything in nutrition, but a 45-to-60-minute lead time is clumsy when a warm-up overruns or a match starts early. A faster, more predictable window is genuinely useful when timing matters.
The research followed the athletes. A 2023 meta-analysis found that caffeinated gum taken roughly 15 minutes before exercise improved performance at doses from around 3mg per kilo of bodyweight, and a 2024 review of 32 studies reported that pre-exercise use supported endurance, repeated sprints and lower-body strength while lowering how hard the effort felt. The common thread isn't a new ingredient — it's the delivery route.
The quiet switch away from the can
Which is what the "switch" is really about. Plenty of athletes didn't cut caffeine; they changed how they take it. Against an energy drink, a pouch means no 250–500ml of liquid to get down before you move, no sugar, and a fixed dose rather than a can you sip through. Against a powder, there's no scoop, no shaker and no washing up — it lives in a pocket, not a gym bag. And because it works through the mouth, there's nothing sitting in your stomach when you start.
None of this is really a secret. It's more that the delivery route spent twenty years inside sports-science journals and elite setups before it turned up in a format anyone could buy — which is why it can feel like something you weren't meant to know about.
What it's actually doing
Stripped of the drama, the job is simple. The caffeine contributes to alertness and concentration¹ — the switched-on feeling you'd want before a session. Most of these pouches pair it with B-vitamins, and B6 and B12 contribute to the reduction of tiredness and fatigue,² which is the part that speaks to the low-energy afternoons and early starts. A small, fast, portable way to line those up for when you need them.
Who's doing it in the UK
In Britain, Sync is one of the brands built around the format — its Performance pouch carries 90mg of caffeine in a mint pouch designed to go in a few minutes before you need it, and the company says it's now trusted by more than 1,000 athletes across the UK.
Whether it replaces your pre-session coffee or just travels better than it, the thing under the lip is less a secret than a format finally catching up to the science.
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¹ Caffeine contributes to alertness and concentration. ² B6 and B12 contribute to the reduction of tiredness and fatigue. See the GB Nutrition and Health Claims Register.
Sources: Kamimori et al. (2002), Int. J. Pharm.; Barreto et al. (2023) meta-analysis on caffeinated gum and exercise; systematic review of 32 studies on caffeinated chewing gum (2024); Frontiers in Nutrition (2023–2026) on buccal caffeine absorption; Fortune Business Insights functional F&B valuation.