What happens when we smile


National Smile Month starts on 13th May and runs until 13th June. When I first saw that it was National Smile Month I assumed that it would be linked to happiness and smiling more. I was mistaken though as it is actually about building awareness of oral health.

Even though the awareness month is not about smiling, I thought I’d write a blog post about what happens when we smile and how we can trick our brain into feeling happier with something as simple as a smile.

So let’s first look at what happens when you smile. When we smile, chemicals such as neuropeptides, endorphins, dopamine and serotonin are released. Neuropeptides have a stress-relieving effect as does serotonin. Endorphins, serotonin and dopamine, commonly known as feel-good chemicals, increase feelings of pleasure, happiness, and satisfaction. Endorphins also act as natural pain relievers.

We smile because we are feeling happy but smiling also makes us feel happy! The process of facial expressions affecting emotions has been referenced as far back as the times of Homer and Shakespeare. Charles Darwin and William James, both theorists on emotion in the 1800s, recognised the importance of facial expressions on emotion. And of course, there has been a lot more research and theorising in this area since.

Adelmann & Zajonc (1989) hypothesised that facial changes involved in smiling have a direct effect on certain brain activities associated with happiness. It’s almost as if your brain cannot tell the difference between a fake smile and a real smile - the same chemical reaction occurs!

Nearly a decade later, Kleinke, Peterson, and Rutledge’s (1998) research also showed that people experience positive moods when they adopt positive facial expressions and decreased positive moods when they engaged in negative facial expressions.

Curiously, cosmetic botox injections in the face to treat lines and wrinkles have been linked to depression. (Lewis, 2018) In a study of people who had received such injections, the facial lines treated influenced how depressed or happy they felt afterwards. Those who had treatment on their frown lines felt less depressed (Lewis & Bowler, 2009) whilst those who had their crow’s feet treated felt more depressed.

Of course, faking a smile isn’t the answer to depression. However, at any given moment, a smile can take the edge off your low mood.

So why wait to be happy before you smile? Get smiling and boost those feel-good chemicals!


  • Kleinke, C.L., Peterson, T.R., & Rutledge, T.R. (1998) Effects of Self-Generated Facial Expressions on Mood. Journal of Personality and Social Psychology. Vol. 74, No. 1

  • Adelmann, P. K., & Zajonc, R. B. (1989) Facial efference and the experience of emotion. Annual Review of Psychology, 40, 249-280.

  • Lewis, M. B. (2018) The interactions between botulinum-toxin-based facial treatments and embodied emotions. Scientific Reports 8, article number: 14720.

  • Lewis, M. B. and Bowler, P. J. (2009) Botulinum toxin cosmetic therapy correlates with a more positive mood. Journal of Cosmetic Dermatology 8(1), pp. 24-26.