NOW Foods Liquid Melatonin is a neuro-hormone (amino acid) naturally produced in the pineal gland in the brain and present in high amounts in the gastrointestinal tract. It is involved in many of the body, brain and glandular biological functions including regulation of normal sleep/wake cycles. This liquid format allows for controlled dosing, and is sweetened with low glycemic sweeteners including Xylitol. It uses all natural flavours.