Did you get your eight hours of beauty sleep last night? If not, you really will be looking noticeably less attractive, according to researchers cited by The Independent Wednesday.

The Swedish study involved observers comparing photographs of volunteers who were well-rested, with photos taken after the same volunteers had been deprived of sleep.

Although the differences were slight, the untrained observers consistently judged the volunteers more unattractive and more unhealthy-looking when less-rested.

"They are small signals, but if you spend a few seconds looking at a face, you instinctively read them," said study leader John Axelsson, of the department of clinical neuroscience at the Karolinska Institute in Stockholm. "These are judgments you make about people without thinking."

The study, published in the British Medical Journal's Christmas issue, was hailed by The Independent as good news for parents trying to encourage vain teenagers to get to bed early -- but bad news for the beauty products industry.

"If you want to look healthy and attractive, it is way better to get a good night's sleep and a lot cheaper than other beauty treatments," said Axelsson.