Lunesta usually starts working within 30 minutes to an hour after ingestion. It has a relatively long half-life of about 6 hours, which can help people fall asleep and stay asleep all night. However, it can also cause side effects such as drowsiness, dizziness, headache, dry mouth and unpleasant taste. Lunestat, like other sleeping pills, should be used for a short time and at the lowest effective dose to reduce the risk of dependence and withdrawal symptoms.