Its recipe is so closely guarded that it is said to be stored in a secure location for use in a national emergency.
And with only three people said to know exactly what goes into Irn–Bru – long hailed by devotees as the ultimate hangover cure – perhaps that level of caution is understandable.
The mythology runs deep. Legendary comedian Sir Billy Connolly once joked that the drink had saved his life ‘on so many Sunday mornings’ – a sentiment that will feel familiar to anyone who has reached for its lurid orange glow after one too many the night before.
But behind the folklore, what is it about Irn–Bru that inspires such loyalty among the bleary–eyed?
And would any self–respecting nutritionist actually endorse it as a remedy for a hangover?
Nichola Ludlam–Raine, specialist dietitian and author of How Not to Eat Ultra–Processed, tells the Daily Mail: ‘Irn–Bru has built a bit of a cult reputation as a hangover cure and there are a few reasons why people feel it works.
‘After a night of drinking, blood sugar levels can dip, and people are often mildly dehydrated. Sugary, fizzy drinks like Irn–Bru provide a quick source of glucose, which may temporarily improve energy levels and reduce feelings of fatigue or shakiness.
‘The carbonation can also help settle nausea for some people, and the distinctive flavour can feel refreshing when appetite is low.’
Irn–Bru is a Scottish soft drink with a secret recipe seen by many as the ultimate hangover cure
What is in Irn–Bru?
Much to the disappointment of many sweet–toothed fans, the sugar content of an original can of Irn–Bru was cut by roughly 50 per cent in 2018, ahead of the UK Government’s sugar tax.
Thousands took the news so badly that a petition named ‘Hands off our Irn-Bru’ was formed, but the reformulation went through anyway.
Today, a standard 330ml can of the drink – which, 125 years after it was first made still has no quantifiable flavour – contains around 15g of sugar, 30mg of caffeine and approximately 62 kcal.
Its listed ingredients include carbonated water, sugar, citric acid, flavourings – including caffeine, ammonium ferric citrate and quinine – along with sweeteners such as aspartame, preservatives and added colouring.
That said, beyond the tongue-in-cheek marketing slogan that it is ‘made from girders,’ the details of Irn-Bru’s secret recipe remain known only to a select few.
As the brand itself jokes on its website: ‘If we told you, we’d have to kill you.’
The nutrition figures differ for its Diet and Zero variants, both of which contain no sugar and just 2 to 3 calories per 330ml can, with the Zero version often described as the sweeter of the two.
For those craving the original sweetness, the brand also introduced its ‘1901’ version – a throwback recipe containing around 36g of sugar and roughly 142 calories per 330ml can.
What happens to your body during a hangover?
For many people, the first signs of a heavy evening drinking alcohol upon waking are intense thirst and dehydration – often accompanied by a pounding headache.
Alcohol acts as a diuretic, meaning it causes the body to lose fluids more quickly through increased urination.
This not only contributes to dehydration but can also leave you reaching for more drinks during a night out, and craving fluids the following day.
A standard can of original Irn–Bru contains around 15g of sugar and approximately 62 kcal
Hangovers can also take a toll on the stomach.
Alcohol irritates the lining, increasing inflammation and stomach acid, which can lead to pain, discomfort, and nausea. In more severe cases, this irritation is what triggers vomiting.
On top of that, blood sugar levels often drop after drinking, which can leave you feeling weak, shaky, or light–headed.
Combined with the fact that alcohol disrupts deep, restorative sleep, it is no surprise that many people wake up feeling exhausted the next day – and craving a sugar fix.
So, should Irn–Bru be used to combat a hangover?
Ms Ludlam–Raine says: ‘Ultimately if someone enjoys Irn-Bru and it helps them feel a bit better, there’s no harm in having it occasionally.
‘However, it’s important to be clear that Irn-Bru isn’t a true cure for a hangover. None of the hangover symptoms are properly addressed by a sugary soft drink alone.’
She also warned that its high sugar content can ‘sometimes lead to a rapid spike and crash in blood sugar, potentially making people feel worse later on’.
Nutritionist and author Jenna Hope agrees, adding: ‘Irn-Bru is often used as a hangover cure as the high caffeine and sugar content provide an additional boost of energy.
‘However, this energy is artificially driven which means you’re likely to experience a worse crash later on in the afternoon. It’s not recommended as a healthy hangover cure.’
What do Irn–Bru say?
The brand themselves offer a somewhat mysterious explanation for the legend surrounding the drink’s supposed ability to cure hangovers.
They say: ‘Many people feel that Irn-Bru is a great pick-me-up generally and there are those that believe it can help with a hangover.
‘People with a hangover tend to be dehydrated so it could be that – or it could be a bit of magic in the secret recipe that no-one can explain.’
Irn–Bru released a ‘1901’ version of the drink containing more sugar like the original recipe
What experts say you should have instead…
Ms Ludlam–Raine says that instead of reaching for any soft drink, rehydrating with water or drinks containing electrolytes such as ‘oral rehydration solutions or milk’ are the best ways to beat a hangover – other than preventing one itself by not drinking in the first place.
She adds: ‘Eating a balanced meal with a mix of carbohydrates, protein and healthy fats (e.g. eggs on wholegrain toast, or yoghurt with fruit may also be effective.
‘You can include gentle, easy–to–digest foods if nausea is an issue, such as toast, bananas or soup.
‘Focusing on hydration, nourishment, and moderation with alcohol in the first place is effective. I advise my patients alternate alcoholic drinks with water in between – keeping to under 14 units a week and spreading this over at least three–to–four days.’
Ms Hope recommends consuming ‘water with a pinch of salt and a splash of orange juice’ which, she says, is ‘a far better way to support optimal hydration’.
She adds: ‘Always ensure you’re drinking a glass of water between alcoholic drinks to reduce the risk of dehydration.
‘Where possible, try to opt for a protein and nutrient rich breakfast such as eggs with avocado on sourdough toast or a protein packed smoothie with yoghurt, banana, oats, peanut butter, spinach and milk and a glass of water as a healthier way to manage a hangover.
‘Additionally, getting some movement in can also help you to feel better, a simple walk in the fresh air can often be more manageable than a heavy gym session.’
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What is YOUR go-to hangover cure?
