We understand melatonin helps with sleep, but in a recent analysis of eight randomized controlled trials, melatonin supplementation was found to improve blood lipid status. Using a meta-analysis approach, a “significant association between melatonin supplementation and a reduction in triglycerides (WMD: −31.54 mg/dL, 95% CI: −50.71, −12.38, p = 0.001) and total cholesterol levels (WMD: −18.48 mg/dL, 95% CI: −35.33, −1.63, p = 0.032)” was observed. No significant effect on LDL-C (WMD: −2.37 mg/dL, 95% CI: −11.61, −6.86, p = 0.615) and HDL-C (WMD: 1.28 mg/dL, 95% CI: −0.66, 3.23, p = 0.197) was found. A sub-group analysis found “a significant decrease in triglycerides at doses ≥8 mg/d when trials last[ed] ≥8 weeks.
In addition, “a significant decrease of total cholesterol was [also] found at doses ≥8 mg/d, and when total cholesterol baseline levels were ≥200 mg/dL.” Overall, the results indicate that melatonin supplementation has notable effects on triglycerides and total cholesterol levels, and is more evident with “higher dose and longer duration, and also [with] a higher concentration of cholesterol levels.” Further studies are required to determine the benefits of melatonin on lipid profile.