Inositol is a molecule with a similar structure as B vitamins that is critical for optimal cellular health. It is found in most vegetable and animal cells and helps support second-messenger signaling pathways, cellular development and structure, antioxidative status, and a healthy inflammatory response. Evidence indicates inositol and its metabolites may also help support the crosstalk between cells and their environment. Because of its many biochemical actions, emerging research suggests it may help support optimal thyroid functioning, reproductive health, blood sugar metabolism, and the function of several other organ systems in the body. 

Of the nine structural forms (isomers) of inositol, three have been identified as particularly supportive of human health: Myo-inositol, D-chiro-inositol (DCI), and scyllo-inositol. Myo-inositol is most abundant in nature and can be converted into DCI through tissue-specific enzymatic reactions. Both Myo-inositol and DCI are thought to support estrogen balance and blood sugar homeostasis. 

A recently published pilot study by Porcaro and colleagues explored inositol’s potential to support health in perimenopausal women experiencing endometrial hyperplasia and abnormal uterine bleeding. Endometrial hyperplasia refers to abnormal tissue enlargement as a result of abnormal cellular proliferation, and may potentially be related to states of unopposed estrogen (i.e., estrogen dominance). Certain abnormalities in insulin homeostasis may also potentially contribute to this pathology; however, this mechanism of action is still not fully understood. 

The pilot study involved thirteen women with endometrial hyperplasia who experienced typical symptoms associated with unopposed estrogen states such as heavy menstrual bleeding. Participants received 600 mg DCI daily for six months. Improvements in endometrial thickness and menstrual length were observed after three months of DCI administration, with greater improvements observed after six months. The number of days of heavy bleeding also improved in the presence of DCI supplementation, with statistically significant improvements observed between the three-month and six-month periods. 

Study strengths include clearly defined primary outcomes and a relatively robust treatment period. Drawbacks include the absence of a control group, a small sample size, and demographic homogeneity. In addition, given DCI’s potential to support hormone balance and metabolic health and their theoretical connection to the etiology of endometrial hyperplasia, another study drawback was the omission of data collection of biometrics related to blood sugar metabolism. Still, the results from this pilot study suggest that more clinical studies are merited.

While more research is needed before clinical conclusions can be made, evidence suggests that inositol may help support certain aspects of hormone balance and endometrial health. It may also help support blood sugar metabolism and optimal cellular health.

By Dr. C. Ambrose, ND, MAT