Melatonin has long been thought of as the “sleep hormone.” It regulates circadian rhythms, the body’s internal biological clock, which can improve sleep patterns. That’s important for optimal health. Inadequate sleep has a well-documented negative impact on immune health, increasing susceptibility to infectious diseases and cancer.1-3 But melatonin does much more. Melatonin provides vital support to the immune system, helping coordinate immune responses to defend against a wide variety of threats, including viruses.4-6 Internal ..