D-Chiro Inositol
What it is
A secondary messenger that mediates insulin signalling in muscle and ovarian tissue. Women with PCOS are deficient in D-chiro inositol due to an enzyme defect impairing its synthesis from myo-inositol. The optimal protocol is myo-inositol:D-chiro inositol in a 40:1 ratio, mirroring the physiological tissue ratio. Multiple RCTs confirm the 40:1 combination restores ovulation, lowers androgens, improves AMH levels, and reduces insulin resistance better than either alone. Critically: high-dose D-chiro inositol alone (600 mg+ without myo-inositol) can paradoxically worsen oocyte quality and reduce ovarian response.
Dose
Take as the 40:1 myo:DCI ratio (most studied: 1,100 mg myo-inositol + 27.6 mg D-chiro twice daily); do not take D-chiro alone at high doses
Time of day & tips
Always take as part of the 40:1 ratio with myo-inositol — standalone high-dose D-chiro inositol is counterproductive for fertility and can worsen oocyte quality. Take morning and evening doses consistently. Effects on ovulation and androgens typically seen within 3 months.
Cycling
Safe for continuous use. Often taken long-term as part of PCOS management. May be reduced or stopped under medical supervision once cycle regulation is achieved.
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