6 Things to Know About Taking Inositol for PCOS

Polycystic ovary syndrome, or PCOS, is caused by a hormone imbalance. It can lead to associated health problems, including diabetes and infertility. Treatment with vitamin-like substances called inositols has shown promising results.

Read on to learn more about inositol supplements and how they may help people with PCOS control blood sugar and increase the chances of becoming pregnant.

Possible Benefits of Inositol Supplements for PCOS Treatment

Verywell / Laura Porter

Inositol Improves Insulin Resistance

Inositols are a kind of sugar the body makes. They help balance chemicals that control your blood sugar and fertility. They also affect your metabolism, the process of turning the food you eat into energy.

Many people with PCOS are insulin resistant. Their bodies make insulin but aren't able to use it effectively. This increases the risk of diabetes, infertility, obesity, and high cholesterol.

Inositols make molecules involved in the body's response to insulin. Researchers say inositols may be part of the body's messaging system when the usual insulin signaling system fails.

You Can Get Inositols From Food and Supplements

You can get inositols by eating healthy foods such as:

  • Fruits: Cantaloupe, grapefruit, other citrus fruits
  • Beans: Lima, navy
  • Grains: Brown rice, whole wheat
  • Nuts: Almonds, walnuts
  • You can also buy inositol food supplements, pills, or powders you mix with water. Inositol supplements are generally well-tolerated.

Inositols MI and DCI Are Beneficial For PCOS

There are nine forms of inositol, but the two that have the biggest impact on PCOS are myo-inositol (MI) and D-chiro-inositol (DCI).

Normally, MI is converted to DCI. But researchers believe people with PCOS may be less able to convert MI into DCI. Lower levels of DCI increase the risk of insulin resistance and high blood sugar.

High MI to DCI Ratio May Contribute to PCOS

In healthy females, most body tissue has an MI to DCI ratio of approximately 40 to 1. This ratio is much higher in people with PCOS.

Combined therapy with MI and DCI is more effective than taking either inositol alone. Specifically, research shows a 40:1 MI/DCI ratio is best for restarting ovulation in people with PCOS.

MI and DCI in a 40:1 ratio may be more effective than Metformin. One study found people with PCOS who took the 40:1 MI/DCI supplement had significantly better ovulation and pregnancy rates (46.7% vs. 11.2%) than those who did not take the supplement.

However, some food supplement companies continue to sell supplements with varying MI/DCI ratios. One review found that the MI to DCI ratio in PCOS products can range from as little as .04-to-1 to as high as 104-to-1.

Some supplements contain only DCI, while others contain additional substances such as vitamins and artificial sugars. There's no evidence to show these ingredients help.

The Right MI to DCI Ratio Improves Fertility

PCOS is a common cause of infertility. Up to 80% of people with PCOS experience infertility challenges.

People with PCOS have an imbalance of MI to DCI in their ovaries. This can affect their:

  • Periods: People with PCOS can have irregular periods or no periods at all. Treatment with inositols has been shown to help improve insulin sensitivity and reduce male hormone levels in females with PCOS. This helps restore periods.
  • Ovulation: People with PCOS might not ovulate every month or at all. Researchers have linked this to having too little MI and too much DCI in the ovaries.
  • Egg quality: Females with PCOS have been shown to produce less mature eggs than females without the disorder. Researchers have linked this to having too little MI in the follicular fluid, which surrounds the eggs within the ovaries.

Eggs can't mature unless there is a high level of MI in the follicular fluid. In healthy females, the MI to DCI ratio in this fluid is about 100 to 1. In infertile females with PCOS, the average ratio of MI to DCI in this fluid is 0.2 to 1.

Inositols can help restore ovulation and improve oocyte (immature egg) quality. But researchers warn taking the correct formulation is essential because high doses of DCI negatively affect oocytes and prevent the body from absorbing MI.

MI Is Used Treat Gestational Diabetes

People with PCOS have an increased risk of gestational diabetes (GD), which is diabetes that develops in pregnancy. A study published in 2019 concluded that people with PCOS have a two-fold higher risk of developing GD than those without PCOS.

Taking MI supplements lowers blood sugar levels and GD risk in people with PCOS. A 2012 study found GD was less common in pregnant females with PCOS who took MI than those who did not take the supplement.


Inositols are sugars the body makes that help regulate insulin and cholesterol levels. Two types of inositols help treat PCOS: MI and DCI.

You can get inositols by eating certain foods or taking food supplements. If you're struggling with infertility, a 40 to 1 MI to DCI ratio appears to be the most helpful. This ratio has also been shown to help lower insulin and cholesterol levels with PCOS.

A Word From Verywell

Research into using combinations of inositol supplements to treat PCOS is very promising. It's also inexpensive compared to some other infertility treatments. If you have PCOS, ask your healthcare provider if it could benefit you.

You may feel tempted to try using inositol supplements on your own. That's not a good idea. Taking too much DCI, for example, can lower your estrogen levels and increase male hormone levels. Estrogen has several benefits like protecting bones and preventing breast cancer. Increasing testosterone levels in females already at risk of infertility also isn't wise.

If your healthcare provider agrees and you decide to try inositols, you may need to be extra careful of what you eat and drink. Some artificial sugars and sugar alcohols weaken the benefit of these supplements.

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16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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