Smiling makes people look healthier and more attractive than being the right weight or even wearing make-up, according to a new study.

Researchers found people whose resting faces seemed cheerful were judged as being in better health than those who appeared miserable.

Their research shows that ‘resting b**ch face’ is not a good idea if you want to be perceived as glowing and attractive.

Scientists decided to try and predict the health ratings of different faces based on their resting expressions.

Psychologists at Swansea University asked volunteers how happy the faces seemed as well as how healthy they appeared.

They found people with genuine smiles, rather than simply looking cheerful or having a blank expression, were even more likely to be seen as healthy and glowing.

And the effect of having a positive expression on perceived health was as powerful as having the correct BMI, plastering on foundation, blusher and mascara or looking young rather than old, the study found.

Dr Alex Jones, a lecturer in psychology at the Welsh university and an expert in facial perception, said they had finally found scientific proof that ‘a smile really is the best accessory.’

He said using fad creams and things like Botox were unnecessary because the secret to looking good is to appear naturally happy.