Melatonin is a supplement you are probably familiar with. It is most commonly used to help with sleep issues, especially in jet lag and in people who work nights. It is a hormone primarily produced in the pineal gland in the brain and helps to regulate sleep and our bodies’ daily cycles/circadian rhythms.
Research on melatonin highlights the possibility of using it for viral infections. Melatonin has shown anti-inflammatory, antioxidant, and immunoregulatory functions. Newer research demonstrates how melatonin can be used in treating viruses. This research shows positive effects in some viruses including West Nile Virus, viral encephalitis, and respiratory syncytial virus (RSV).
Viral infections wreak havoc on our immune systems by creating excessive inflammation, oxidation, and a collection of immune responses that often lead to a reaction called a cytokine storm. A cytokine storm is an inflammatory response where the immune system overproduces more inflammatory markers than it needs. This overactive immune response can progress to acute respiratory distress syndrome (ARDS) and other complications. There is speculation that melatonin will reduce the signals that lead to a cytokine storm and decrease the serious effects from these viruses. 
Melatonin is an affordable, safe, and low risk option for supporting viral infections in this current medical crisis. It can be helpful in both preventative and adjunct treatment. The dosage of melatonin depends on the patient and the severity of the viral infection. It is important to work with a qualified health practitioner in determining the dose appropriate for you. If you are looking to add this to your protocol, make sure to talk with your doctor before starting any new supplement or medication.
 Silvestri, M., & Rossi, G. A. (2013). Melatonin: its possible role in the management of viral infections–a brief review. Italian journal of pediatrics, 39, 61. https://doi.org/10.1186/1824-7288-39-61
 Zhang, R., Wang, X., Ni, L., Di, X., Ma, B., Niu, S., Liu, C., & Reiter, R. J. (2020). COVID-19: Melatonin as a potential adjuvant treatment. Life sciences, 117583. Advance online publication. https://doi.org/10.1016/j.lfs.2020.117583