Circadin is a prescription medication primarily used to treat sleep disorders such as insomnia, particularly in individuals who experience difficulty falling asleep. The active ingredient in Circadin is melatonin, a hormone naturally produced by the pineal gland in the brain, which helps regulate the sleep-wake cycle. Circadin is formulated as a prolonged-release tablet, designed to mimic the body's natural release of melatonin, gradually releasing the hormone over a few hours. This medication is often recommended for short-term use in adults aged 55 and over, aiming to improve the quality of sleep and help regulate the sleep pattern. It is important to follow a healthcare provider's instructions when using Circadin to ensure its effectiveness and minimize potential side effects.