For a study, researchers sought to evaluate the effect of dietary supplements on the progression of symptoms and quality of life in individuals with mild-to-moderate COVID-19 infection. They modified the Wisconsin Upper Respiratory Symptom Survey (WURSS) to undertake a 3 arm, parallel, randomized, double-blind, placebo-controlled investigation with individuals who had mild-to-moderate symptoms of COVID-19 infection. Patients were given either a placebo (n=34), 1,000 mg of vitamin C (n=32), or 10 mg of melatonin (n=32) for a period of 14 days. With a mean age of 52 years, 88 patients—98 of the 104 recruited—completed the trial. Results were calculated as differences from baseline scores for each of the 2 WURSS-derived surveys, and they were then looked at with a spline regression analysis. Patients receiving vitamin C and placebo both saw the same rate of symptom progression. When compared with those taking placebo (coefficient = -1.09 (95% [CI] = -1.39 to -0.8) the melatonin group saw a quicker remission of symptoms compared to the placebo group (coefficient=-0.63 [95% CI] -1.02 to -0.21] P=.003). Day 14 saw a plateau for all 3 groups. The group receiving vitamin C improved at the same rate as the group taking a placebo, according to a study on the impact of quality-of-life interventions (coefficient = -0.71 (95% CI = -1.11 to -0.3)). The quality of life improved more quickly in the melatonin-taking group (coefficient = -1.16 (95% CI = -1.75 to -0.57) P<.005). Day 14 saw a plateau for all 3 groups. Vitamin C intake of 1000 mg per day does not affect the onset of disease. Taking 10 mg of melatonin daily may have a statistically significant effect for people with mild-to-moderate COVID-19 infection symptoms, while it is unclear if this will have a clinically relevant benefit. More study was required.