Melatonin is a hormone synthesized and released by cells in the pineal gland. It controls the day-night rhythm of the human body and promotes sleep. The European Food Safety Authority (EFSA) considers it scientifically proven that melatonin helps to alleviate the subjective sensation of jet lag and to reduce the time it takes to fall asleep. Melatonin also has endocrine effects and affects the functioning of the immune system. Current scientific studies have shown positive effects on various diseases.