Melatonin for pets is specifically formulated to deliver the right amount of melatonin - a hormone released by the pineal gland, which regulates the sleep-wake cycle, plays an important role in the regulation of biological rhythms and mood, has strong antioxidant properties and has been shown to have many beneficial effects in dogs and Cats. In dogs and Cats, melatonin plays an important role in the synchronization of the circadian rhythms, including in sleep-wake timing, as well as seasonal reproduction. As a supplement, melatonin is often used when having trouble sleeping.