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. 2026 Jan 27;23:27. doi: 10.1186/s12986-025-01061-5

Table 1.

Characteristics of studies that evaluated the effect of melatonin supplementation on blood glycemic indices

Author, Year Location Design Gender Duration (week) Enrolment, n Intervention(n) Control (n) Age,
mean
Type of intervention Type of placebo Dose
(mg/d)
Population BMI
(Kg/m2)
mean
BaselineFBS (mg/dl)
Seabra et al. [52] Brazil RP M:40 4 40 30 10 Total: 29 Capsule (Melatonin) Capsule (Powder) 10 Healthy NA 88.3
Gonciarz et al. [50] Poland RP F: 13, M:18 4 31 16 15 IN: 42.1, CL:40.5 Capsule (Melatonin) Capsule (Powder) 10 NASH 28.6 89.27
Gonciarz et al. [50] Poland RP F:16, M:26 12 42 30 12 IN: 41.5, CL:40.8 Capsule (Melatonin) Capsule (Powder) 10 NASH NA 80.15
Grieco et al. [29] USA

RC

Wash out: 6 weeks)

F:10, M:4 6 14 7 7 IN:52.5, CL:52.5 Capsule (Melatonin) Capsule (white flour) 10 T2DM NA 141.98
Goyal, A. et al. [2013] USA

RC2A

Wash out: 6 weeks)

F:22, M:17 10 39 39 38 IN:62.7, CL:57.6 Capsule (Melatonin) Capsule (lactose powder) 8 MetS 34.6 102.2
Romo-Nava, F. [53] Mexico RP F:22, M:22 8 44 20 24 IN:30.6, CL:28.6 Capsule (Melatonin) Capsule (Powder) 5 bipolar disorder and schizophrenia 26.1 88.8
Modabbernia, A. et al. [30] Iran RP F: 11, M:25 8 36 18 18 IN:32.7, CL:32.8 Tablet (Melatonin) Tablet (Powder) 3 Schizophrenia 23.9 85.4
Amstrup, A. K. et al. [46] Denmark RP F: 72 48 72 37 35 IN: 62.4, CL:62.9 Capsule (Melatonin) Capsule (Powder) 2 postmenopausal women 23.6 96.55
D’Anna, R. et al. [54] Italy RP F:32 24 32 16 16 IN:49.1, CL:48.7 Capsule (Melatonin + myoinositol) Capsule (myoinositol) 3 postmenopausal women 26.7 NA
Raygan, F. et al. [2017] Iran RP F:33, M:27 12 60 30 30 IN:67.7, CL:65.3 Capsule (Melatonin) Capsule (Powder) 10 T2DM with CHD 30.4 170.9
Agahi, M. et al. [32] Iran RP F:49, M:51 8 100 50 50 IN:37.4, CL:37.46 Capsule (Melatonin) Capsule (Powder) 3 Schizophrenia 25.1 NA
Ghaderi, A. et al. [33] Iran RP M:54 12 54 26 28 IN:42.5, CL:42.7 Capsule (Melatonin) Capsule (Powder) 10 patients under methadone maintenance treatment 24.8 95.1
Shabani, A. et al. [34] Iran RP F:58 12 58 29 29 IN:26.5, CL:26 Capsule (Melatonin) Capsule (Powder) 10 PCOS 27.1 94.9
Farrokhian, A. et al. [35] Iran RP F:33, M:37 9 70 34 36 IN:57.74, CL:57.61 Tablet (Melatonin) Tablet (Powder) 6 T2DM 29.33 151.09
Bahrami, M. et al. [36] Iran RP F:24, M:46 12 70 36 34 IN:42.5, CL:42.6 Tablet (Melatonin) Tablet (Powder) 6 MetS 31 105.7
Bahrami, M. et al. [37] Iran RP F:14, M:31 12 45 24 21 IN: 44, CL:37.71 Tablet (Melatonin) Tablet (Powder) 6 NAFLD 29.46 103.25
Daneshvar Kakhaki, R. et al. [38] Iran RP F:19, M:32 12 51 25 26 IN:64.4, CL:66.3 Capsule (Melatonin) Capsule (Powder) 10 Parkinson’s Disease 25.1 100.6
Abood, S. J. et al. [55] Iraq RP F:35 12 35 20 15 IN:45.8, CL:48.07 Capsule (Melatonin) Capsule (lactose powder) 10 MetS 40.24 125.4
Ostadmohammadi, V. et al. [39] Iran RP F:15, M:38 12 53 26 27 IN:65.6, CL:64.1 Capsule (Melatonin) Capsule (Powder) 10 T2DM Hemodialysis 26.4 127.1
Anton, D. M. et al. [56] Romania RP F:21, M:29 8 50 25 25 IN:53.24, CL:52.21 Tablet (Melatonin) Tablet (Powder) 3 T2DM NA > 126
Bazyar, H. et al. [40] Iran RP F:34, M:16 8 50 25 25 IN:53.64, CL:51.52 Capsule (Melatonin) Capsule (Powder) 3 T2DM 27.38 172.04
Esalatmanesh, K. et al. [41] Iran RP F:51, M:13 12 64 32 32 IN:49.31, CL:49.44 Capsule (Melatonin) Capsule (Powder) 3 Rheumatoid arthritis 27.29 106.19
Satari, M. et al. [42] Iran RP F:19, M:27 12 46 22 24 IN:66.9, CL:64.3 Capsule (Melatonin) Capsule (Powder) 10 T2DM nephropathy 28.8 138
Alizadeh, M. et al. [43] (i) Iran RP3A F:41 8 41 21 20 IN:25.57, CL:26.2 Tablet (Melatonin) Tablet (Powder) 6 PCOS 28.4 82.47
Alizadeh, M. et al. [43] (ii) Iran RP3A F:42 8 42 21 21 IN:25.57, CL:25.57 Tablet (Melatonin) Tablet (magnesium oxide) 6 PCOS 28.4 82.47
Kim, Y. et al. [57] Korea RP F:38 6 38 19 19 IN:61, CL:61 Capsule (Melatonin) Capsule (Powder) 2 Insomnia 24.9 98
Lauritzen, E. S. et al. [47] Denmark RP M:17 12 17 9 8 IN:65, CL:62 Capsule (Melatonin) Capsule (Powder) 10 T2DM 29 139.09
Bazyar, H. et al. [44] Iran RP F:22, M:22 8 44 22 22 IN:53.72, CL:53.3 Tablet (Melatonin) Tablet (Powder) 6 T2DM 27.21 173.59
de Sousa, C. A. R. et al. [48] Denmark

RC

Wash out: NA)

F:46 12 46 23 23 Total: 37.1 Tablet (Melatonin) Tablet (Powder) 3 Healthy night shift workers 29.9 89.7
Hannemann, J. et al. [58] Germany RP F:11, M:13 12 24 12 12 IN:38.3, CL:34.8 Tablet (Melatonin) Tablet (Powder) 2 Healthy night shift workers 26.1 87.1
Alamdari, Naimeh Mesri. et al. [45] Iran RP F:44 6 44 22 22 IN:33.86, CL:34.86 Tablet (Melatonin) Tablet (Powder) 6 Obese women > 30 98.17

RP: Randomized Parallel design, RC: Randomized crossover design, RC2A: Randomized crossover two-armed design RP2/3A: Randomized Parallel two/three-armed design, BMI: Body Mass Index, F: Female, M: Male, NASH: nonalcoholic steatohepatitis, T2DM: Type 2 diabetes mellitus, MetS: Metabolic Syndrome, CHD: Coronary Heart Disease, PCOS: Polycystic Ovarian Syndrome, NAFLD: nonalcoholic fatty liver disease, FBS: fasting blood sugar