If you’ve ever been approached by a stranger who tells you to ‘smile’, you may be having a bad day or you could be suffering from Bitchy Resting Face (BRF). The phenomenon rose to fame last year after a comedic YouTube clip went viral, and has been confirmed by experts as an expression when a woman looks thoughtfully sad or angry for no reason. Naturally, as we age and our faces sag a little more, this look gets easier and easier to master – even if it’s the last thing you want to achieve.

“It’s over-activity of the muscles,” says Dr Catherine Stone from the Face Place. “We develop a lot of the lines of expression on our face through repeated contraction of the muscles which break down the collagen fibres in our skin. When we’re younger, we can repair the damage, but as we age we start to do more damage that can’t be repaired… that’s when you start to notice those lines and wrinkles.”

Long before the term BRF was coined, there was a journal paper in 2003 called Social Implications of Hyperfunctional Facial Lines. The study looked at facial miscues that occur when the lines or facial expressions are etched into the skin by over-active muscles, and the emotional message they send to society even if they don’t reflect how you feel.

“A key example of that is the grumpy frown – the lines that appear in between your brows,” Stone says. “A lot of my clients will come in about the grumpy frown, which sends the message of being grumpy, stressed or tired when they’re perfectly happy. They’ve even had people say to them ‘Don’t worry, dear – it’s not that bad’.”

This phenomenon has been the driving force behind skincare trends for the past year, with the creation of lifting, sculpting, firming, filling creams and serums in an attempt to keep your face looking serene. Click through to find out how to turn that frown upside down: