Want to feel happier, and even ward off depression? Smile – even if you have to fake it! Research has found that smiling slows down our heart rate, reduces stress, and improves our mood. That’s because we tend to smile when we feel safe, which naturally lowers our stress levels. And in another study, researchers found that frowning less – say, by injecting Botox into frown lines – can help relieve depression. Because when you can’t frown, it reduces the production of stress hormones. Essentially, we can influence our mental health by what we do with our face!

To prove all this, researchers at UC Irvine had people do a stressful task. Then, some of them were asked to bite down on a chopstick – like a dog holding a stick – which uses the same facial muscles as a big smile does. While others were told to hold the chopstick in their mouth, but to keep their lips closed. The result? Those using their smile muscles saw a huge drop in heart rate!

The researchers also did a study on frowning – in which volunteers, who had been diagnosed with depression, were injected with Botox so they couldn’t frown, while another group got a placebo. A month later, 27 percent of the Botox group was no longer clinically depressed – a number that was 4 times higher than those who got the placebo.

So, how can you make this work for you? Smile during difficult tasks. Long-distance runners say that smiling reduces the mental stress of marathons. You can also practice smiling in ordinary situations. Body language expert Patti Wood charges $1,200 to teach people positive body language. And here’s what she tells her clients: Involve your whole face in a smile. That means, bring your cheeks up higher, and make sure your eyes are crinkling at the edges. And every time you’re in the grocery store, practice that smile. Ask yourself: “How does that make me feel?” and “How are people reacting?” Then break out that smile as needed.