Most people take melatonin 10mg supplements on a short-term basis to relieve temporary sleep issues, such as those caused by jet lag. Melatonin can also help some people, such as shift workers or those with delayed sleep-wake phase disorder, reset their internal body clocks to get better sleep. While melatonin is primarily known as the sleep hormone, melatonin supplements can serve other functions beyond regulating sleep, including anxiety relief prior to surgery.