Improvements in LDL cholesterol and blood pressure have been shown in as few as two months of melatonin use (5 mg/day, two hours before bedtime) in thirty patients with documented metabolic syndrome who had not responded to a three-month intervention of therapeutic lifestyle modifications (1). Further, melatonin has been shown to decrease nocturnal hypertension, improve systolic and diastolic blood pressure, reduce the pulsatility index in the internal carotid artery, decrease platelet aggregation, and reduce serum catecholamine levels (2–5). A recent meta-analysis and systematic review by researchers at The Chinese University in Hong Kong concluded that a controlled-release oral melatonin supplement reduced asleep systolic blood pressure by 3.57 mm Hg (2).
Cai et al. (6) correlated low levels of endogenous melatonin to decreased long-term survival in patients with pulmonary hypertension. As illustrated, multiple mechanisms are involved with the pleiotropic abilities of melatonin that not only have been shown to have antioxidant, inhibition of oxidative stress, and anti-inflammatory effects but also in inducing vasodilation, cardio-protective, cancer-protective, and benefits in respiratory diseases. Melatonin levels were attributed to hyper-activation of the sympathetic system and/or the renin-angiotensin system in patients with pulmonary hypertension (6).
Other studies have shown that melatonin improves outcomes in patients with heart failure and is considered a preventive and adjunctive curative measure in these patients (5). A randomized double-blinded placebo-controlled clinical trial with two parallel arms using either placebo or oral 10 mg melatonin supplementation per day for twenty-four weeks in patients with heart failure and reduced ejection fraction observed improvements in endothelial function in those who did not also have diabetes (7).
There has been some discussion as to whether melatonin may be helpful in conditions involving glycemic control, such as in non-insulin-dependent type 2 diabetes. A recent, relatively small, placebo-controlled study in male diabetics showed reduced insulin sensitivity by 12% after 10 mg of melatonin for three months (8). The difference in effects of melatonin on oral glucose tolerance in the diabetic population may involve polymorphisms in the type 2 diabetes-associated G allele in the melatonin receptor-1B gene (MTNR1B) (9–11). In one clinical trial with Spanish type 2 diabetics (12), the relationship between endogenous melatonin, dietary carbohydrate, and the effects of late-night eating were investigated. It was found that glucose tolerance was impaired in the late versus the early eating condition, especially in MTNR1B G-risk allele carriers, known to have insulin secretion defects. While this type of genotype is not easily assessed through current clinical laboratory assessment, it is best to monitor melatonin supplementation and any changes in blood sugar response in patients with glycemic control issues.
Authors: Deanna Minich, Ph.D., Melanie Henning, ND, Catherine Darley, ND, Mona Fahoum, ND, Corey B. Schuler, DC, James Frame
Reviewer: Peer-review in Nutrients Journal
Last updated: September 22, 2022
1. Koziróg M, Poliwczak AR, Duchnowicz P, Koter-Michalak M, Sikora J, Broncel M. Melatonin treatment improves blood pressure, lipid profile, and parameters of oxidative stress in patients with metabolic syndrome. J Pineal Res. 2011;50(3).
2. Lee EKP, Poon P, Yu CP, Lee VWY, Chung VCH, Wong SYS. Controlled-release oral melatonin supplementation for hypertension and nocturnal hypertension: A systematic review and meta-analysis. J Clin Hypertens. 2022 May 1;24(5):529–35.
3. Simko F, Baka T, Paulis L, Reiter RJ. Elevated heart rate and nondipping heart rate as potential targets for melatonin: a review. Journal of Pineal Research. 2016.
4. Pandi-Perumal SR, BaHammam AS, Ojike NI, Akinseye OA, Kendzerska T, Buttoo K, et al. Melatonin and Human Cardiovascular Disease. Vol. 22, Journal of Cardiovascular Pharmacology and Therapeutics. 2017.
5. Nduhirabandi F, Maarman GJ. Melatonin in heart failure: A promising therapeutic strategy? Vol. 23, Molecules. 2018.
6. Cai Z, Klein T, Geenen LW, Tu L, Tian S, van den Bosch AE, et al. Lower plasma melatonin levels predict worse long-term survival in pulmonary arterial hypertension. J Clin Med. 2020;9(5).
7. Hoseini SG, Heshmat-Ghahdarijani K, Khosrawi S, Garakyaraghi M, Shafie D, Roohafza H, et al. Effect of melatonin supplementation on endothelial function in heart failure with reduced ejection fraction: A randomized, double-blinded clinical trial. Clin Cardiol. 2021;44(9).
8. Lauritzen ES, Kampmann U, Pedersen MGB, Christensen LL, Jessen N, Møller N, et al. Three months of melatonin treatment reduces insulin sensitivity in patients with type 2 diabetes—A randomized placebo-controlled crossover trial. J Pineal Res. 2022 Aug 1;73(1).
9. Garaulet M, Gómez-Abellán P, Rubio-Sastre P, Madrid JA, Saxena R, Scheer FAJL. Common type 2 diabetes risk variant in MTNR1B worsens the deleterious effect of melatonin on glucose tolerance in humans. Metabolism. 2015;64(12).
10. Kampmann U, Lauritzen ES, Grarup N, Jessen N, Hansen T, Møller N, et al. Acute metabolic effects of melatonin—A randomized crossover study in healthy young men. J Pineal Res. 2021;70(2).
11. Lopez-Minguez J, Saxena R, Bandín C, Scheer FA, Garaulet M. Late dinner impairs glucose tolerance in MTNR1B risk allele carriers: A randomized, cross-over study. Clinical Nutrition. 2018;37(4).
12. Garaulet M, Lopez-Minguez J, Dashti HS, Vetter C, Hernández-Martínez AM, Pérez-Ayala M, et al. Interplay of Dinner Timing and MTNR1B Type 2 Diabetes Risk Variant on Glucose Tolerance and Insulin Secretion: A Randomized Crossover Trial. Diabetes Care. 2022;45(3).