It's the fashionable pick-me-up of choice that enables the exhausted to get back on their feet. For some it comes in a little tab that dissolves on the tongue; for others it's administered via syringe.

This is not some class-A drug, but Vitamin B12. In some quarters, “it's time for my vitamin shot” may be a euphemism, but not in the world of Madonna. She, apparently, has been using it as an excuse to get young men to drop their trousers. And, as one of the men in question is Justin Timberlake, who can blame her? By all accounts it was slightly terrifying: “She looks at me and says: ‘Drop 'em.' She gives me a B12 shot in my ass, then she says: ‘Nice top shelf.'”

Indeed. But Madonna is not the only famous overachieving female to use B12: it was supposedly prescribed to Baroness Thatcher, who famously ran a whole country on less than five hours' sleep a night. I tried it once myself, and it's true what they say: it gives you more energy than a pair of toddlers after two packets of Haribos. No wonder Madge is so unstoppable.

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