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Inositol

Myo-inositol

Supplements. Modern nutrition.

Also called D-chiro-inositol, Vitamin B8 (unofficial name)

Pinyin: jī chún

Spanish: Inositol

Can affect blood sugar

A sugar-like compound found in beans, citrus and whole grains, most often taken by women with polycystic ovary syndrome (PCOS).

Did you know? Inositol was first found in muscle tissue in 1850, and its name comes from the Greek word for muscle.

What it may help, and how strong the proof is

Women's health. In women with PCOS, several trials and a 2017 meta-analysis of 10 trials found more regular cycles and more ovulation. Evidence for live births is weak, and a Cochrane review rated it low quality. It is not a replacement for standard PCOS care.See the research: 121 studies in people
Promising proof
Blood sugar. Some small trials in women with PCOS report better insulin use, which is how well the body handles insulin. Pooled analyses have not found a clear, consistent change, so this is not a substitute for diabetes medicine.See the research: 214 studies in people
Traditional proof
Low mood. Early small trials at high doses, about 12 grams a day, reported fewer panic attacks and some mood gains. Later trials have been mixed, so the proof is weak.See the research: 101 studies in people
Traditional proof

Parts of the body

Hormones & reproduction, Pancreas & blood sugar, Brain & mind

Traditional use

Inositol is not part of old herbal healing traditions. It came from 1800s chemistry and was studied later as a nutrient. Some sellers call it vitamin B8, but it is not an official vitamin.

How it is classified

Herbal actions: Nutritive, Hormone balancer. Energy: neutral.

How people take it

PCOS studies mostly used about 2 to 4 grams a day, often split into two doses, over several weeks to months. Early panic and depression trials used much higher amounts, around 12 grams a day, which is not a typical supplement dose.

Powder, capsule and food.

Where to get it

Your body makes inositol from glucose. Food sources include beans, nuts, whole grains, citrus fruit and cantaloupe. Supplements come as powders and capsules. Many PCOS products use myo-inositol with a small amount of D-chiro-inositol, often at a 40 to 1 ratio.

Be careful

Usually well tolerated. High doses can cause bloating, gas, diarrhea or nausea. People with diabetes should watch blood sugar, since inositol may change insulin levels, though the effect is small and inconsistent. Safety in pregnancy is not well established, so check with a doctor before use.

Avoid if: pregnancy; breastfeeding.

Mixing with other things

Works well together
Some PCOS support blends combine inositol with vitamin D. Research on the combination is limited.
Use caution
Diabetes medicine (metformin, insulin, glipizide, Ozempic)
Effects on blood sugar are small and inconsistent, so watch levels if you take diabetes medicines.
Worth knowing
Lithium (for bipolar disorder)
Lithium and inositol act on some of the same brain signals. Combined use is not well studied, so ask a doctor first.

Adds up with others that may lower blood sugar: , , , , , , , , , , , , , and 54 more.

The honest take

Inositol is a food-like compound that many people tolerate well, and some PCOS research is promising. The overall evidence is still mixed and low in quality. It may help some women with cycles, and insulin effects are small and inconsistent, but there is no reliable proof that it raises live birth rates. Panic and mood claims come from early trials that have not been consistently repeated.

Sources

Each “See the research” link opens PubMed, the U.S. National Library of Medicine's index of medical studies, showing only trials and reviews done in people. The number tells you how much a use has been tested, not whether it worked. The proof rating tells you that.

Study counts checked October 2026.