What Is Inositol? Myo-Inositol Explained

Many people see «inositol», «myo-inositol» or «vitamin B8» on supplement labels without knowing what it really is. Women reading about PCOS, menstrual cycles or planning a pregnancy run into the name especially often. This article explains in plain words what inositol is, where it occurs, what research says and who should be careful.

What is inositol and why is it called vitamin B8?

Inositol is a natural sugar-like compound. It is part of cell membranes and takes part in passing signals inside cells. The body can also make inositol from glucose, so strictly speaking it is not a vitamin. Even so, it has long been called «vitamin B8», and supplement labels use that name.

When people say «inositol», they usually mean myo-inositol, the most common form in the body and in food. «Inositol», «inositol myo» and «myo-inositol» are the same substance.

Myo-inositol vs D-chiro-inositol: what is the difference?

Inositol exists in several forms (isomers). The two mentioned most often are myo-inositol and D-chiro-inositol. They are chemically similar but do different jobs in the body.

Feature	Myo-inositol	D-chiro-inositol
Where it occurs	The most common form in the body and in food	Made in the body from myo-inositol; also sold separately in some supplements
In research	Best studied in PCOS and insulin sensitivity	Often studied together with myo-inositol
In Nutva Inositol	Yes (1000 mg)	No

The 2023 international PCOS guideline cannot yet say which type, dose or combination of inositol is best, because high-quality evidence is lacking.

Which foods contain inositol?

Inositol occurs naturally in many plant foods: grains and bran, legumes (beans, peas, mung beans), nuts, citrus and other fruit. Someone who eats a varied diet already gets some inositol from everyday food. The exact amount is hard to calculate because it depends on the food and how it is processed.

Supplements contain much more, in a standardised amount. But a supplement does not replace healthy eating; it can only complement it.

Inositol and PCOS: what does research say?

PCOS (polycystic ovary syndrome, called PMOS in some sources) can involve irregular periods, delayed or absent ovulation, excess hair growth and acne. The cause is not fully known; an interplay of hormones such as insulin and testosterone may play a role. You can read more in our PCOS guide.

Inositol is discussed most often in exactly this context. The current scientific picture:

International guideline (2023). Inositol (in any form) could be considered by women with PCOS based on individual preferences and values. Harm is limited and metabolic measures may improve, but clinical benefit for ovulation, excess hair growth or weight is limited. The quality of evidence is rated low.
Cochrane review (2018). In subfertile women with PCOS, it could not confirm that myo-inositol improves pregnancy or live birth rates: the evidence was of low to very low quality, and adverse effects were poorly reported.

Put simply: inositol does not treat PCOS and is not a guaranteed answer to infertility. Doctors sometimes discuss it as an addition to the overall approach. The core of PCOS care is lifestyle (food, activity, sleep) and, when needed, treatment prescribed by a gynaecologist or endocrinologist.

Does inositol affect insulin sensitivity and mood?

Inositol is studied as part of the signalling molecules involved in how cells respond to insulin, so researchers have also looked at it in insulin resistance. The 2023 guideline speaks cautiously of a «potential for improvement in metabolic measures» but adds that clinical benefit is limited.

There are small studies on mood, anxiety and sleep, but they are not yet enough for reliable conclusions. So it is more accurate to see inositol not as a «calming» product but as a substance that may support normal nervous system function and cellular processes.

Inositol and folate (5-methylfolate): why are they often together?

Many supplements pair inositol with folate. The reason is simple: folate (vitamin B9) matters especially when planning a pregnancy. WHO recommends that every woman take 400 mcg of folic acid daily from the moment she starts trying to conceive until 12 weeks of pregnancy, to help prevent neural tube defects. NHS gives the same advice and stresses starting before conception.

5-methylfolate is an active form of folate. How it differs from folic acid and which form suits you is best decided with your doctor. See also our article on vitamins when planning a pregnancy.

Who might discuss inositol with a doctor?

Inositol usually comes up for women with irregular periods, a PCOS diagnosis or plans for a pregnancy. In that situation the right first step is to find the cause: hormones, blood sugar, an ultrasound and a check of general health. Inositol should not «cover up» the cause; it should fit into the overall plan your doctor builds.

Doctors most often start with lifestyle: moderate eating, less sugar and white bread, regular activity, enough sleep. According to the 2023 guideline, such changes can benefit metabolic health even without weight loss.

Is inositol safe and does it have side effects?

The PCOS guideline notes limited harm from inositol and points out that it causes fewer gastrointestinal complaints than metformin. However, the Cochrane authors say adverse effects were poorly recorded in trials, so safety cannot be considered fully proven. Some people may feel mild digestive discomfort.

Take special care if you are:

pregnant or breastfeeding — only after consulting a doctor;
taking diabetes medicines — inositol may affect sugar metabolism, so tell your doctor first;
living with chronic conditions or taking other supplements.

The guideline also reminds that quality control and regulation of inositol supplements can differ from medicines. Choose only a product with a permit and a clearly identified manufacturer.

When to see a doctor

After reading about inositol it is easy to suspect PCOS, but only a doctor can diagnose it. See a gynaecologist or endocrinologist if:

your periods are often late, very infrequent or have stopped;
hair growth on the face, chest or abdomen increases sharply, with worsening acne and hair loss;
you gain weight without a clear reason, fat gathers around the waist, or dark thick patches appear on the neck or armpits;
you have been trying to conceive for a long time without success;
high blood sugar is found or you notice signs of diabetes (strong thirst, frequent urination, weakness);
you have severe lower abdominal pain, very heavy bleeding, or suspect pregnancy with a missed period.

Medicines and other treatment for PCOS are prescribed only by a doctor. Always tell your doctor about any supplements you take.

How Nutva Inositol can help

Nutva Inositol is a dietary supplement (BAA) made by NUTVA PHARM MChJ (Uzbekistan). One capsule contains 1000 mg myo-inositol (vitamin B8) and 200 mcg 5-methylfolate (vitamin B9) (2 capsules: 2000 mg and 400 mcg). The pack holds 60 pieces. The product supports normal nervous system function and cellular processes.

Permit number: №1594430 (Ministry of Health of Uzbekistan).
The product is not a medicine.
During pregnancy, breastfeeding, or if you take diabetes medicines — only after consulting a doctor. It does not replace PCOS treatment prescribed by a gynaecologist or endocrinologist.
How to take it — follow the instructions on the pack and your doctor's advice.

A supplement does not replace a balanced diet, sleep, physical activity or medicines prescribed by your doctor.

Frequently asked questions

Is inositol a vitamin or a medicine?

Inositol is a natural substance the body also makes itself, loosely called «vitamin B8». It is not a medicine; as part of a dietary supplement it does not replace medicines.

Why do women need inositol?

Inositol takes part in cell signalling and is discussed in women's health because of its link with the ovaries and insulin processes. Research results are limited, so whether to take it is best decided with a doctor.

Does inositol help you get pregnant?

The Cochrane review could not confirm that myo-inositol raises the chance of pregnancy; evidence quality is low. If you are planning a pregnancy, see a doctor first and get tested.

Can I take inositol during pregnancy or breastfeeding?

Only after consulting a doctor. Do not start it on your own.

How should inositol be taken?

The exact dose and duration are given in the instructions on the pack; agree them with your doctor. The 2023 international guideline also cannot recommend a universal dose.

Are myo-inositol and D-chiro-inositol the same?

No, they are two different forms of inositol. Nutva Inositol contains myo-inositol.