Table 1.

Characteristics of included studies

Citation (First author et al., year)	No. of Studies in Meta-analysis	Location Duration of intervention	No. of Participants in Meta-analysis	Intervention/daily dose	Quality Assessment Scale and Rating	Measured outcomes and Results
Kutbi et al. 2021	23	Saudi Arabia 11	1516 with metabolic diseases	Cinnamon/2.2 g/day	Yes (Cochrane) 23/23 were low	FPG (↓), HOMA (↓), HbA1C(↓), Insulin (↓)
Heshmati et al.2021	5	Iran 8-52wk	289 with PCOS	Cinnamon /0.5–1.5 g/day	Yes (Cochrane) 3/5 were high	FPG(↓), HOMA(↓), insulin(↓)
Heydarpour et al.2020	5	Iran 6-24wk	448 with PCOS	Cinnamon/ 0.336-1.5 g/day	Yes (Cochrane) 3/5 were high	FPG(↓), HOMA (↓), insulin (↓)
Namazi et al.2019	18	Iran 6-17wk	1100 with T2DM	Powder and extract of cinnamon/ 1–6 g/day of powder and 0.12 − 0.5 g/day of extract	Yes (Cochrane) 13/18 were low	FPG (↓), HbA1C (↓)
Deyno et al.2019	16	Uganda 4-16wk	1098 with T2DM	Cassia, aromaticum, zeylanicum and verum/1-14.4 g/day	Yes (Cochrane) 8/16 were high	FPG (↓), HOMA (↓), HbA1C(Ns), Insulin (↓)
Ainehchi et al.2019	16	Iran NR	668 with PCOS	Cinnamon /without restrictions regarding dose	Yes (Cochrane) 7/16 were high	FPG (↓)
Allen et al.2013	10	USA 4-18wk	543 with T2DM	Aqueous cinnamon extract or raw cinnamon powder/0.12-6 g/day	Yes (Cochrane) 5/10 were high	FPG (↓), HbA1C (Ns)
Akilen et al.2012	6	UK 6-16wk	375 with T2DM	Cinnamomum cassia/1–6 g/day	Yes (Cochrane) 2/6 were high	FPG (↑), HbA1C (↑)
Leach et al.2012	6	Australia 4-16wk	577 with T2DM	Cassia, Chinese cinnamon and burmanii/2 g/day	Yes (Cochrane) 3/10 were high	FPG(Ns),HbA1C (Ns),insulin (Ns)
Davis et al.2011	8	USA 4–16 wk	369 with T2DM	1–6 g cinnamon and 250 mg-3 g cinnamon extract	Yes (Cochrane) 3/8 were high	FPG(↓)
Baker et al.2008	4	USA 12	207 with T2DM	Cinnamon/3.5 g/day	NR	FPG (Ns), HbA1C(Ns)

Abbreviations: PCOS, Polycystic Ovary Syndrome; T2DM, type 2 diabetes mellitus;FPG;Fasting blood glucose, HbA1C;Hemoglobin A1C,HOMA; homeostatic model assessment, NS; Not significant, NR; Not reported