Published: 00:01 BST, 25 August 2026 | Updated: 12:03 BST, 25 August 2026
If your daily coffee shop visit leaves you feeling a bit twitchy and your heart pounding, there’s a very good reason.
It turns out that some drinks deliver nearly as much caffeine as experts recommend for a whole day.
Which? experts discovered the strength varied ‘wildly’ between high street chains, whether in a straight black coffee, a cappuccino or a trendy matcha latte.
Analysis of the levels of caffeine from five popular retailers put Costa Coffee’s medium cappuccino and americano at the top with 325mg of caffeine, the same as four 250ml cans of Red Bull.
Costa also had the strongest matcha latte, with 99mg, whereas Starbucks’ matcha green tea latte contained 57mg – more than a shot of its espresso, which was 45mg.
Which? said: ‘This could be a shock for non-coffee drinkers looking for jitter-free energy.’
The organisation’s health and wellbeing expert Jessica Carson said: 'For many of us, there is nothing quite like a strong cup of coffee to start the day, but Which? found even matcha enthusiasts could be consuming more caffeine than intended.
'Our research shows caffeine content varies wildly from chain to chain. If you drink multiple cups a day or need to cut back for health reasons, pay attention to where you shop and what you order to avoid any unwanted side-effects.'
The Which? team analysed the amount of caffeine in popular drinks sold at Caffe Nero, Costa, Greggs, Starbucks and Pret A Manger.
This included espressos, cappuccinos, filter coffees, flat whites, americanos and matcha lattes.
For reference, The British Heart Foundation advises that up to 400mg of caffeine a day is considered safe for most adults.
Overall, Costa's medium cappuccino and americano had the highest levels. The second and third-highest cappuccino caffeine levels, Greggs and Caffe Nero, were significantly below Costa, with 235mg and 221mg, respectively.
When it came to a single shot of espresso, Pret A Manger's offering was the strongest, containing 180mg of caffeine.
That's four times as much as the espresso from Starbucks, which has just 45mg of caffeine.
