1D-chiro-Inositol[2] or D-chiro-inositol[3] (often abbreviated DCI) is a chemical substance with formula C6H12O6, one of the nine isomers of cyclohexane-1,2,3,4,5,6-hexol (which may be collectively called "inositol").

[4][5] The common isomer myo-inositol is converted into DCI in the human body by an insulin dependent enzyme, NAD/NADH epimerase.

It accelerates the dephosphorylation of glycogen synthase and pyruvate dehydrogenase, rate limiting enzymes of non-oxidative and oxidative glucose disposal.

[3] DCI depresses the expression of the steroidogenic enzyme aromatase, which is responsible for the conversion of androgens to estrogens.

[3] One pilot study found males taking DCI had increased androgens and reduced estrogen.