Can Melatonin & Vitamin D Help Prevent COVID-19?

As life begins to transition back to “normal,” COVID-19 is still a threat. Research shows vitamin D and melatonin work together to help prevent COVID-19 and reduce your risk of severe illness if you are exposed to the virus. New variants and the increasingly hard-to-reach goal of herd immunity mean that protecting yourself is more imporant than ever.

Nutrients Work Together

Due to a combination of marketing and misinformation, many people think of the different biological compounds as unique individual pieces. For example, the stress hormone cortisol is often viewed as “bad,” when in reality cortisol can be life-saving. It becomes a major problem only when chronically elevated.

Most of the compounds in the body act in a coordinated manner. In the case of the endocrine system, the hormone melatonin and the pro-hormone vitamin D have many shared actions. They work in a cascade-like fashion, impacting the release of other substances in the body.

Research into the coordinated effect of vitamin D and melatonin is still in the early phases, but one area of interest in the time of COVID-19 is how they strengthen the immune system and prepare the body to avoid an infection. If there is an infection, vitamin D and melatonin can reduce the high mortality rate (1).

How Do They Protect The Immune System?

Scientists zeroed in on melatonin and vitamin D to prevent COVID-19 because they both moderate immune function. Plus, they are often depleted in older adults who are at greater risk of severe illness from COVID and other viruses, such as the flu. Melatonin and vitamin D are also directly involved in the health of the lungs (1).

Vitamin D Improves The Body’s Immune Defenses

Vitamin D directly raises levels of immune cells that attack invading pathogens. Studies consistently show an association between vitamin D deficiency and increased risk of developing respiratory infection and viruses.

One randomized trial of 140 immunodeficient patients found that daily supplementation of 4,000 IUs of vitamin D over one year significantly reduced infectious symptoms and lowered the number of specific pathogens in the nasal fluid (2).

In the case of COVID-19, people who are deficient in vitamin D are more likely to be hospitalized from COVID-19 and mortality rates are higher (3, 4, 5).

Fortunately, vitamin D supplementation is protective: Studies consistently show that people with higher vitamin D levels are less likely to test positive for COVID and COVID patients with healthy vitamin D levels have better outcomes and recover more quickly than those with lower vitamin D levels (6).

Melatonin Supports Immune Function

Best known as the sleep hormone, melatonin is also a powerful anti-inflammatory hormone. It has been shown to suppress lung injury and inflammation in several disorders that affect the lungs, including asthma, cigarette smoking, and lung fibrosis (7). Pretreatment with melatonin is also effective in reducing lung damage in patients subjected to chemotherapy and it has been shown to prevent COPD.

Melatonin has anti-viral action, serving as an antioxidant and raising levels of protective enzymes, such as glutathione peroxidase and superoxide dismutase. Melatonin may also help regulate apoptosis and autophagy, or the cleaning up of damaged cells, in the lungs (7). One recent study found that people who supplemented with melatonin had a 30 percent reduction in the chance of having a positive COVID test compared to those who were not supplementing (8). Among African Americans, the protective effect was even greater with melatonin use resulting in a 52 percent lower risk of contracting COVID-19.

Melatonin and Vitamin D Help Prevent COVID Together

Melatonin and vitamin D appear to have a synergistic effect on raising immune function and protecting against viruses. In the case of COVID, we know that the coronavirus enters host cells by binding its spike protein to ACE2 receptors that allow the body to manage blood pressure and fluid balance in the body (1). Melatonin and vitamin D protect these cells from a “cytokine storm” that occurs when inflammatory molecules attack healthy lung tissue in COVID.

Take Aways:

Melatonin and Vitamin D have shared mechanisms that allow them to strengthen the immune system and prevent COVID-19.

Monitoring vitamin D levels can be done with a blood test. A level below 20 ng/ml is a deficiency. A level between 20 and 30 ng/ml is considered Low. Above 30 ng/ml is considered Adequate.

For individuals with a vitamin D deficiency, in the absence of sun exposure, 2,000 to 7,000 IUs of vitamin D3 per day should be sufficient to bring serum levels above 30 ng/ml (9). Supplementation should be individualized and some individuals may require higher or lower doses to achieve healthy vitamin D levels.

For melatonin, there are currently no dosing recommendations for immune function or COVID due to a lack of research. Studies testing the effect of melatonin on sleep show that doses ranging from 0.3 to 10 mg can improve sleep in insomniacs and healthy sleepers.

Both vitamin D and melatonin are associated with deeper, longer sleep. Simply improving sleep can support immune function since sleep is the time when the body produces disease-fighting white blood cells. Sleep is necessary for production of the “master antioxidant” glutathione, which is the linchpin of your body’s ability to counter oxidative stress that compromises immunity. Sleep is also when growth hormone is released that allows your innate immune system to function optimally (10).