Myo-Inositol: What It Is and the Benefits for Women

Inositol is a naturally occurring form of sugar that's responsible for a seriously impressive amount of processes in your body. This little sugar helps regulate hormones such as thyroid-stimulating hormone, follicle-stimulating hormone, and insulin, making it a key player in many metabolic and hormonal functions. Inositol is also found in some foods (including corn, legumes, meat, and some fruits), and it’s sometimes taken in the form of a supplement known as myo-inositol. 

Myo-inositol first rose to popularity among people with polyendocrine metabolic ovarian syndrome (PMOS, formerly known as polycystic ovary syndrome, or PCOS) and those interested in fertility treatments. It’s been found to improve the metabolic profiles, egg quality, and menstrual regularity in people with PMOS. 

Inositol supplements have also been studied as a possible alternative to the insulin-regulating diabetes drug metformin. Now people who are in perimenopause and menopause are interested in myo-inositol’s potential to regulate metabolism and hormones.

As the research stands, myo-inositol can benefit people who need supplementation without causing major side effects, as long as it’s taken in small doses. However, that doesn’t necessarily apply to everyone, which is why taking it under a clinician’s supervision is recommended. 

Read on to learn more about inositol benefits (including inositol benefits for women), how much inositol per day is generally recommended, and safety info to know. (And book a visit with a Midi clinician for personalized guidance about what’s best for your health.)

What Is Myo-Inositol?

Inositol is a form of sugar that the body naturally creates and needs for the growth and development of cells. It’s found in some foods, including corn, legumes, meat, and some fruits. In supplement form, inositol is known as myo-inositol and is sometimes referred to as vitamin B8, though it is not a true vitamin.

In reading about myo-inositol, you may also hear about its isomer (a fraternal twin of sorts), d-chiro-inositol, which has the same chemical makeup but exists in a different arrangement. In healthy women, the blood plasma ratio of myo-inositol to d-chiro-inositol is 40 to 1. 

Because of that, supplement makers often combine the two to re-create and match that ratio, though the combination has really only been researched and tested for the treatment of PMOS and fertility. Still, it’s helpful information that’s in the process of being applied to potential menopause therapy.

How Does Myo-Inositol Work in the Body?

Myo-inositol acts as a messenger that helps cells respond to important hormones, including insulin. Think of it as a proverbial tap on the hormones’ shoulders, signaling them to do their jobs.

This is particularly noteworthy for people with insulin dysfunction (think: those with diabetes, PMOS, and other conditions), as insulin is a huge pillar of metabolic health that influences blood sugar, ovulation, and metabolism. 

Myo-Inositol Benefits for Midlife Women

Insulin sensitivity—or a change in the way the body responds to and processes insulin—is a common occurrence for women in perimenopause and menopause that coincides with the natural decline of estrogen in midlife. That insulin shift can lead to weight changes, energy shifts, muscle loss, and other hallmark symptoms of menopause. 

In theory, evidence suggests that inositol benefits for women could include defense against menopause-related insulin sensitivity and blood sugar dysregulation. When lots of glucose is present in the blood (meaning: your blood sugar is high), both glucose and myo-inositol compete for entry into cells. 

During digestion, myo-inositol can slow down how much glucose is absorbed from food, so blood sugar doesn’t spike after eating. In muscles, it can help cells use glucose more effectively. However, when too much glucose causes an imbalance between the two, problems can happen. This is where supplementation may help even the playing field—but it still doesn’t replace prescription medications when needed.

Can Myo-Inositol Help With Sleep and Mood?

Myo-inositol might be helpful in regulating mood shifts associated with menopause, as some studies show it may be beneficial for panic disorders. Still, it’s not a mainstay treatment for mood changes.

While research on myo-inositol for sleep is minimal, it has been found to help with sleep quality and duration in pregnant women, due to its possible impacts on the brain. More research is needed to understand the phenomenon, though. 

Myo-Inositol, PMOS, and the Perimenopause Overlap

Many women who have used myo-inositol for PMOS are curious about whether or not to continue it into perimenopause. It’s true that the hormone imbalances between the two conditions can overlap, but they’re not exactly the same.

“The common thread here is insulin,” explains Ava Mainieri, PhD, Midi’s Vice President of Clinical Operations, whose research specializes in biology and genetics. “In PMOS, the body doesn't respond well to insulin, so it makes extra.” 

Through a few processes, that extra insulin results in extra testosterone floating around, “which makes muscle even less responsive to insulin, so the cycle feeds itself,” says Mainieri.

In perimenopause and menopause, a similar thing takes place via a different route. Estrogen drops, but the ovaries and adrenal glands continue making testosterone at roughly their previous pace, which creates a hormone imbalance with relatively higher testosterone levels compared to estrogen. 

“Endocrinologists call this ‘relative androgen dominance,’ aka a change in the ratio of hormones, not the production,” Mainieri explains. “On top of that, losing estrogen shifts fat storage toward the middle and makes muscle less efficient at pulling sugar out of the blood.”

These conditions are clearly complex, which is why it’s best to discuss potential myo-inositol use with an experienced healthcare professional, like a Midi clinician.

How Much Myo-Inositol Should You Take?

Knowing how much inositol per day to take depends on a person’s needs. But generally, “the dose that matters is 4 g per day,” says Mainieri. “That number shows up in essentially every study that worked. The clearest proof that dose matters comes from a review of gestational diabetes prevention: 4 g per day cut the rate substantially, while a low-dose blend of about 1 g showed no benefit on anything measured. Inositol peaks in the blood within 1 to 3 hours and clears through the kidneys, and levels stabilize within a few days of regular dosing. Taking all 4 g at once means a spike, then a drop.”

For PMOS, the general recommended supplement formulation is a 40 to 1 ratio of myo-inositol to d-chiro-inositol, with study participants receiving 2  g of inositols twice a day for 3 months. Meanwhile, for prediabetes or insulin resistance, daily doses of 18 g for 3 months or 4 g for 12 months have been noted as safe and well-tolerated. 

As with any supplement or medication, it’s best to discuss adding something new to your regimen with a licensed healthcare professional, like a Midi clinician. They can help narrow down the specifics and recommended dose to help you meet your health goals.

Cautions and Interactions

Because myo-inositol lowers blood sugar, you should use caution if you are taking other antidiabetes medications, as the combination may result in hypoglycemia (low blood sugar).

It’s also advised to use caution if taking inositol alongside berberine or fenugreek. Because all of these supplements have hypoglycemic (blood sugar–lowering) actions, they are usually not used in combination with one another.

Finally, know that your body may absorb less myo-inositol if you take the supplement alongside a high-glucose meal (think: a dinner with lots of starchy foods, added sugars, or refined carbs), as they’ll compete for absorption in your gut.

Is Myo-Inositol Safe? Side Effects and Cautions

Myo-inositol is generally well tolerated, with the main side effect being mild digestive upset when taken in larger doses. 

Even so, it’s best taken under the supervision of a clinician, especially during pregnancy, if you’re taking other prescription medications (such as those for blood sugar management), or if you are being treated for existing conditions. 

How to Choose a Quality Myo-Inositol Supplement

When you seek out any supplement, myo-inositol included, prioritize brands that use research-backed ingredients, have transparent labeling, and use third-party testing to ensure purity, potency, and quality. 

Also know that you may find ingredients lists that feature myo-inositol-only and those that have combined myo-inositol and d-chiro-inositol. The supplements are available in both capsule and powder forms, and what you choose will depend on your preference and the dose you need. 

In general, inositol supplements are best incorporated into your wellness regimen with the help of clinician guidance.

Key Takeaways

• Myo-inositol is the supplement-form of the sugar inositol, which is naturally occurring in the body and found in some foods.
• The sugar helps with the development of cells and regulation of certain hormones, including insulin.
• It has been found to assist with blood sugar regulation in people with diabetes and PMOS.
• There is promise for the supplement to support menopausal symptoms related to estrogen decline and insulin sensitivity, but clinician guidance is advised.

Frequently Asked Questions (FAQs)

What does myo-inositol help with?

Myo-inositol has been found to help with blood sugar and hormone regulation, particularly as it relates to insulin resistance. People with diabetes and PMOS have shown improvements when taking the supplement, and it shows similar promise for metabolic menopause symptoms. In some studies, myo-inositol has also been shown to help with certain mood disorders including panic disorders and depression.

Who shouldn’t take myo-inositol?

People who don’t have abnormal blood sugar, insulin resistance, or hormone dysregulation will likely not benefit from taking myo-inositol. Specifically, because myo-inositol lowers blood sugar, you must use caution if you are taking antidiabetes medications or other blood sugar–lowering supplements like berberine or fenugreek, as the combination can cause hypoglycemia (dangerously low blood sugar). Talk with your clinician before taking any supplement, including myo-inositol.

Can inositol help with OCD?

There is a small amount of evidence that supports the effectiveness of myo-inositol for obsessive-compulsive disorder (OCD) symptoms, but more research is needed to fully understand its benefits. 

Does inositol lower AMH?

More studies are needed to fully understand myo-inositol’s effects on anti-Müllerian hormone (AMH). People with PMOS have elevated AMH, due to ovarian dysfunction. Some data suggests that myo-inositol can lower AMH in people with PMOS, which may reflect improving ovarian function. But again, we need more data.