6 Things to Know About Taking Inositol for PCOS

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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, which is 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.

Does Inositol for PCOS Make You Gain Weight?

It depends on the individual. Imbalances in your levels of inositols are associated with weight changes, including weight loss and weight gain. Studies have found these weight changes are linked primarily to how myo-inositol (MI) is metabolized in the body. For many people with PCOS, inositol-based therapies may lead to weight loss.

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 Benefits 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.

MI/DCI Supplements

It is important to note that MI:DCI ratios vary in different body tissue, but in the ovary, healthy females have a ratio of approximately 100:1. PCOS patients tend to have a much higher level of DCI and very low levels of MI, leading to an abnormally low MI:DCI ratio of 0.2:1.

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.

Two grams, twice a day, is currently considered the optimal inositol for PCOS dosage. The best time to take inositol is just before eating.

MI to DCI and 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:

  • 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: Eggs can't mature unless there is a high enough level of MI in the follicular fluid. 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.

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

MI Used to 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.

Side Effects and Cautions

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.

Additionally, inositol for PCOS has been linked to hair loss as well as excessive hair growth. Some people with PCOS also experience acne, which can be treated with other medications.

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.

Dosing Variations

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.

Summary

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 supplement 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.

19 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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Additional Reading

By Angela Grassi, MS, RDN, LDN
 Angela Grassi, MS, RDN, LDN, is the founder of the PCOS Nutrition Center.