inositol

How to Choose an Inositol Supplement

Pelvic Floor Doctor
Medically Reviewed By Dr. Amanda Olson, DPT, PRPC

The word inositolmay be sounding more and more familiar to you these days, as evidence on its benefits continues to emerge. But what is it?

Inositol is a naturally occurring nutrient created by the body by breaking down glucose. It also occurs naturally in some foods such as cantaloupe, fresh citrus fruit, legumes, and whole grain bread.

Though it is sometimes referred to as “Vitamin B8”, it is not actually a vitamin. It is more accurately described as a type of sugar that plays a role in many physiological processes, such as endocrine and neurotransmitter function. 

In addition to being found in certain foods and being created by your body, it is also available in supplement form. The most common forms of inositol supplements are called D-chiro-inositol, inositol hexophosphate (“IP6”), and myo-inositol. Though they are similar in structure, they have different effects on the body. 

Inositol supplements have been studied and recommended for their role in increasing insulin sensitivity, which can help with conditions such as metabolic syndrome, polycystic ovary syndrome (PCOS), gestational diabetes, and diabetes mellitus.

It can also affect neurotransmitter function, which can help with certain mood disorders like anxiety, panic attacks, and depression.

However, as with any supplement, there are some considerations to keep in mind when choosing the right one for you. Here are some things to look for:

Safety and Side Effects

Inositol supplements, though not regulated by the Food and Drug Administration (FDA), are given the classification of “generally regarded as safe” as a food or dietary supplement, with little to no risk of overdose. In general, side effects tend to be limited to mild gastrointestinal discomfort, even with higher doses.

There are some risks associated with certain conditions, however. Even though inositol can be helpful in people with diabetes, its use may lead to hypoglycemia (low blood sugar) in some people, so it is important to carefully discuss the supplement with your doctor if you have diabetes. 

Similarly, there is some concern over its use in people with bipolar disorder, as it may cause manic episodes. This effect is being studied more carefully.

Certain populations, such as children and pregnant or breastfeeding women, should discuss this supplement with their doctor before using.

Though it is often used with pregnant women at risk for gestational diabetes and is deemed safe, large-scale trials are still needed to confirm its widespread use in this population (Formoso et al., 2019).

Type and Dosage

The inositol supplements that are most widely found on the market are myo-inositol and D-chiro inositol, which both occur naturally in the body. While they are similar, they play different roles in insulin signaling. When the body is functioning normally, a portion of myo-inositol is converted to d-chiro inositol.

People with certain conditions, such as PCOS, can have disruptions in this conversion process, which is what may lead to the insulin resistance that is found in this condition.

The type of inositol for different conditions is still not consistently agreed upon. The ratio of myo-inositol to d-chiro inositol that naturally occurs in the body is 40:1, so some research argues that supplements that maintain this same ratio are maximally effective in treating conditions like PCOS and other conditions (Caputo et al., 2020). 

Studies report inositol supplementation in doses of 2-4 g/day for most conditions, though some studies report using much larger doses of 12-18g/day in patients with depressive disorders, without adverse effects (Caputo et al., 2020).

The mild gastrointestinal side effects such as nausea, diarrhea, and gas are associated more with these higher doses. Most studies have only looked at short term use of inositol supplementation and more research is needed to determine if they are safe for long term use.

Production

Look for supplements that are labeled “Made in a GMP registered facility”, which means “good manufacturing process”. This means that the manufacture follows the stringent standards established by the FDA for the manufacturing and handling of dietary supplements.

Finally, as with any supplement, there may be interactions between medications, food, and the supplement. You should always discuss the supplement with your healthcare provider before you begin using it.

References

Caputo, M., Bona, E., Leone, I., Samà, M. T., Nuzzo, A., Ferrero, A., Aimaretti, G., Marzullo, P., & Prodam, F. (2020). Inositols and metabolic disorders: From farm to bedside. Journal of Traditional and Complementary Medicine, 10(3), 252–259. https://doi.org/10.1016/j.jtcme.2020.03.005

Formoso, G., Baldassarre, M., Ginestra, F., Carlucci, M. A., Bucci, I., & Consoli, A. (2019). Inositol and antioxidant supplementation: Safety and efficacy in pregnancy. Diabetes/metabolism research and reviews, 35(5), e3154. https://doi.org/10.1002/dmrr.3154