We’ve all heard the phase beauty sleep, but is there actually any truth to it? Can sleep actually make you more attractive?

Researchers from Sweden sought to find the answer. They took two photos of the same person, but with one crucial difference. The first photo was taken after a full 8 hours sleep, while the second photo was taken after two nights of just 4 hours sleep. People were brought in to rate the photos. The photos of the people who were well rested were judged to be more attractive, healthier, and the respondents said they were more likely to approach them to socialize, as opposed to the ones who had just 4 hours sleep.

So sleep does make us look more attractive, but research hot off the press from the University of Berkeley in California has shown that sleep also strengthens marriages. Each couple in the study kept a sleep dairy and also noted how much they appreciated their partner. The researchers found a link between good sleep and positive relationships, and were able to conclude that sleep makes couples work well together, appreciate one another, and experience fewer relationship problems.

These two studies are just one of many that show beauty sleep boosts initial attractiveness while also improving long term relationships. Take a look at the infographic below for even more ways that sleep makes you more attractive.