Melatonin is a neurohormone produced in humans by the pineal gland. A favorite of travelers, it governs the body's circadian rhythms. Melatonin is also a potent antioxidant. The Benefit of Sublinguals Some nutrients may break down during liver metabolism. The sublingual form is absobed directly into the bloodstream, via the blood vessels under the tongue, and in the cheeks, bypassing the liver and allowing for quick entry into the system.