Windmill Sleep Soundly Liquid Melatonin delivers 10 mg of fast-acting melatonin per serving in a convenient liquid form. Melatonin is a naturally occurring hormone that plays a key role in regulating the body’s sleep and wake cycle. This non-habit-forming supplement is designed to support a restful night’s sleep and help promote relaxation before bedtime. The liquid formula makes it easy to adjust serving size and take just before bed. Windmill has been providing trusted, high-quality supplements for over 50 years, manufactured in the USA under strict quality standards.