Table 2.

Summary of the reported studies about myo-inositol and D-chiro-inositol use in PCOS treatment.

Study (first author, year)	MI and/or DCI dosage and duration	Main outcomes
Nestler, 1999 [38]	1200 mg of DCI/die versus placebo for six to eight weeks	In the group treater with DCI: (i) Area under the plasma insulin curve after the oral administration of glucose decreased (ii) Serum free testosterone concentration decreased (iii) Diastolic and systolic blood pressure decreased (iv) Plasma triglyceride concentrations decreased (v) Ovulatory rate increased
Laganà, 2015 [64]	1 gr of DCI/die plus 400 mcg of folic acid/die for 6 months	(i) Significant reduction of systolic blood pressure, Ferriman-Gallwey score, LH, LH/FSH ratio, total testosterone, free testosterone, Δ-4-androstenedione, prolactin, and HOMA index (ii) Significant increase of SHBG, glycaemia/IRI ratio, and menstrual cycle regularization
Pizzo, 2014 [65]	4 gr of myo-inositol/die plus 400 mcg of folic acid/die versus 1 gr of D-chiro-inositol/die plus 400 mcg of folic acid/die for six months	(i) MI compared to DCI decreased mostly systolic arterial pressure, LH/FSH ratio, total testosterone, D-4-androstenedione, prolactin, HOMA index, and, at the same time, SHBG considerably rises (ii) DCI compared to MI decreased more LH and free testosterone; at the same time, glycaemia/IRI ratio increased (iii) Both MI and DCI caused menstrual cycle regularization
Genazzani, 2008 [66]	MI 2 gr plus folic acid 200 mcg every day versus folic acid 200 mcg every day for 12 weeks	In the group treater with MI: (i) Plasma LH, prolactin, testosterone, insulin levels and LH/FSH resulted significantly reduced (ii) Insulin sensitivity expressed as glucose-to-insulin ratio and HOMA index resulted as significantly improved (iii) Menstrual cyclicity was restored in all amenorrheic and oligomenorrheic subjects
Gerli, 2003 [68]	100 mg, twice a day (=200 mg every day) of inositol (not specified if MI of DCI) versus placebo	(i) The ovulation frequency was significantly higher in the treated group compared with the placebo; the time in which the first ovulation occurred was significantly shorter (ii) The circulating concentration of E2 increased only in the inositol group during the first week of treatment (iii) Significant weight loss and leptin reduction were recorded in the inositol group (iv) Significant increase in circulating high density lipoprotein was observed only in the inositol treated group
Donà, 2012 [15]	MI 1200 mg/day versus placebo for 12 weeks	(i) MI treatment significantly improved metabolic and biochemical parameters (significant reductions were found in IR and serum values of androstenedione and testosterone) (ii) A significant association between band 3 tyrosine phosphorylation levels and insulin area under the curve was found at baseline but disappeared after MI treatment, while a correlation between band 3 tyrosine phosphorylation and testosterone levels was detected both before and after MI treatment
Nordio, 2012 [69]	550 mg MI + 13,8 mg DCI/day versus 2 gr MI/day for 3 months	(i) Plasma glucose and insulin concentrations showed a significant reduction in the MI + DCI group while no relevant changes were reported in the treatment with MI alone (ii) Compared to the MI group, the decrement of total testosterone and the increment of the serum SHBG were more relevant in MI + DCI group
Minozzi, 2013 [70]	550 mg MI + 13,8 mg DCI/day	(i) Improved LDL levels, HDL, triglycerides, and HOMA-IR.

MI: myo-inositol; DCI: D-chiro-inositol; LH: luteinizing hormone; FSH: follicle-stimulating hormone; SHBG: sex hormone binding globulin; E2: estradiol; HOMA: Homeostasis Model Assessment; IRI: glycaemia/immunoreactive insulin; IR: insulin-resistance; LDL: low density lipoprotein; HDL: high density lipoprotein.