Every September, Australians are encouraged to ask someone a simple question: "Are you OK?"

R U OK? Day is Australia's most recognizable mental health campaign and a familiar part of workplace coffee breaks, school assemblies and social media feeds.

But does it actually improve mental health? Our new study suggests it does. We found a small but measurable improvement in mental well-being after R U OK? Day. The gain was largest among men ages 25–49.

But we found no increase in visits to a GP for a mental health treatment plan or in prescriptions filled for mental health-related medications.

Together, these findings show both the value and the limits of public awareness campaigns.