One of the commonest sights the morning after payday, wherever workmen in Scotland gather to build something, is a scattering of empty Irn Bru bottles as far as the eye can see.
Irn Bru is feted as a sovereign ameliorative, if not a down-right cure, for hang-overs throughout Scotland. Why?
Well, after a lifetime's investigation into this, putting the very lives of my own brain cells at risk, here is my guess.
It contains water, and lots of it. Most of the ill-effects of a hangover are caused by dehydration.
(Most of the rest is from the liver finishing metabolising the ethanols and by-products and starting onto the methanols, etc. 'Hair of the dog' is an attempt to put off that evil moment by adding ethanol back in to the body for the liver to process preferentially).
It contains sugar, and lots of it. The body needs fuel at this point, and it makes the water easier to ingest.
It contains caffeine - in fact, Irn-Bru is about half-way between Coca-cola and Jolt Cola in this regard - which acts as a stimulant, making you feel better and accelerating the processing of the toxic by-products in your body.
And last, and far from least, it contains bubbles, which increase the surface area from which the sugars and caffeine can get into the bloodstream. (This is also why champagne, cava and other sparkling wines bring on mild drunkenness so quickly).
In fact the only thing that that could improve Irn-Bru as a hang-over remedy would be the addition of fruit juice so there were vitamins and minerals in it to replace the ones drained out while you were drunk, and an isotonic formula to make the fluid seep back into your dehydrated body cells faster and more readily.
Several years ago, Barrs brought out Irn-Bru XS - a drink that addressed these very points!
Other products available in the family are Irn-Bru chews, Diet Irn-Bru, and the rest of the A.G. Barrs soft drinks line: ginger beer, Red Kola, Limeade, Pinappleade, Strike Cola, Lemonade, Soda Water, etc., etc. Recently their Jusoda drink has been deprecated in favour of Orangina, which they now make and market in the UK under licence.