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Melatonin and health: an umbrella review of health outcomes and biological mechanisms of action

Posadzki, Pawel P.; Bajpai, Ram; Kyaw, Bhone Myint; Roberts, Nicola J.; Brzezinski, Amnon; Christopoulos, George I.; Divakar, Ushashree; Bajpai, Shweta; Soljak, Michael; Dunleavy, Gerard; Jarbrink, Krister; Nang, Ei Ei Khaing; Soh, Chee Kiong; Car, Josip


Pawel P. Posadzki

Ram Bajpai

Bhone Myint Kyaw

Amnon Brzezinski

George I. Christopoulos

Ushashree Divakar

Shweta Bajpai

Michael Soljak

Gerard Dunleavy

Krister Jarbrink

Ei Ei Khaing Nang

Chee Kiong Soh

Josip Car


Our aims were to evaluate critically the evidence from systematic reviews as well as narrative reviews of the effects of melatonin (MLT) on health and to identify the potential mechanisms of action involved.

An umbrella review of the evidence across systematic reviews and narrative reviews of endogenous and exogenous (supplementation) MLT was undertaken. The Oxman checklist for assessing the methodological quality of the included systematic reviews was utilised. The following databases were searched: MEDLINE, EMBASE, Web of Science, CENTRAL, PsycINFO and CINAHL. In addition, reference lists were screened. We included reviews of the effects of MLT on any type of health-related outcome measure.

Altogether, 195 reviews met the inclusion criteria. Most were of low methodological quality (mean -4.5, standard deviation 6.7). Of those, 164 did not pool the data and were synthesised narratively (qualitatively) whereas the remaining 31 used meta-analytic techniques and were synthesised quantitatively. Seven meta-analyses were significant with P values less than 0.001 under the random-effects model. These pertained to sleep latency, pre-operative anxiety, prevention of agitation and risk of breast cancer.

There is an abundance of reviews evaluating the effects of exogenous and endogenous MLT on health. In general, MLT has been shown to be associated with a wide variety of health outcomes in clinically and methodologically heterogeneous populations. Many reviews stressed the need for more high-quality randomised clinical trials to reduce the existing uncertainties.

Journal Article Type Article
Acceptance Date Dec 20, 2017
Online Publication Date Feb 5, 2018
Publication Date 2018
Deposit Date Aug 30, 2022
Publicly Available Date Sep 1, 2022
Journal BMC Medicine
Publisher BMC
Peer Reviewed Peer Reviewed
Volume 16
Issue 1
Article Number 18
Keywords Melatonin, Health, Effectiveness, Umbrella review, Systematic reviews, Meta-analyses
Public URL


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