Effect of melatonin on serum lipids in patients with hypercholesterolemia: a pilot study

Indirect evidence suggests that melatonin may lower serum cholesterol. We undertook a pilot study to assess the effect of melatonin on serum lipids in patients with hypercholesterolemia. Patients with a low-density lipoprotein (LDL) level greater than 160 mg/dL despite a 3-month trial of a low-fat diet were enrolled. Patients were randomized in a single-blind, cross-over fashion to receive placebo, 0.3 mg melatonin, or 3 mg melatonin at bedtime for 6 weeks. Serum lipids (total cholesterol, triglycerides, high-density lipoprotein, LDL) were obtained at baseline and after each treatment arm. The means of the lipid components were compared between placebo and each active treatment arm. Statistical analysis was performed using repeated-measures analysis of variance. Twenty-one patients were enrolled in the study. Five patients dropped out of the study, two because of side effects to melatonin and three because of protocol violations. There was no statistically significant difference in lipid components between placebo and both melatonin doses. There was a trend toward a decreased total cholesterol and LDL with the 3-mg dosage. Three patients had significant decreases in LDL on 3 mg melatonin. At the dosage studied, melatonin had no uniform effect on serum lipids in patients with hypercholesterolemia.