It's a treatment designed to get rid of those pesky laughter lines, but it seems Botox could be doing its job too well. According to a psychologist at Cardiff University, the 'muscle-freezing' injections could actually cause depression.
Dr Michael Lewis claims that because the treatment prevents us from smiling properly, it cuts off the 'happy' signals sent to the brain - and that could indirectly lead to users feeling blue.
Conducting a study of 25 women who had Botox injections or facial fillers to minimise frown lines and crow's feet, Dr Lewis, whose previous research revealed that treatment for frown lines reduced feelings of depression, investigated the effect the popular jabs had on mood.
Each of the volunteers completed questionnaires rating their symptoms of depression between two and four weeks after having the treatment, and those who had their crow's feet treated reported a score more than 50 per cent higher than those who fixed their frown.
According to the Daily Mail, Dr Lewis said: "The expressions we make on our faces affect the emotions we feel. We smile because we are happy but smiling also makes us happy.
"Treatment with drugs like Botox prevents the patient from being able to make a particular expression.
'For example, those treated for frown lines with Botox are not able to frown as strongly. This interrupts the feedback they would normally get from their face and they feel less sad."
He hoped to encourage women to embrace their wrinkles, saying: "They should be encouraged to celebrate the emotions they express and enjoy the laughter lines - they are there for a reason."
So while a little Botox every now and then might turn that frown upside down, perhaps it's best to leave the laughter lines well alone.
What do you think? Have you experienced feelings of depression after Botox treatment? Leave your comments below...