Inositol

What inositol is

Inositol is a compound with a ring of six carbon atoms, each carrying a hydroxyl group. It exists in nine forms called stereoisomers. Myo-inositol is the most common of them in food, and the body also makes inositol itself. On a supplement label you will see either "inositol" or "myo-inositol".

Myo-inositol or inositol on the label

OstroVit names the form and sells myo-inositol as a powder with no other ingredients. NOW Foods and Swanson label their capsules simply as inositol and do not name the form. If you want a product that states myo-inositol on the label, choose the OstroVit powder.

Inositol on its own or with choline

Choline and inositol products contain two separate substances in one capsule. Both NOW Foods and Swanson put 250 mg of choline, from choline bitartrate, and 250 mg of inositol in each capsule. If you are comparing inositol amounts, a capsule with inositol alone holds two or more times as much as a combined capsule.

Powder or capsules

The OstroVit powder gives 1000 mg in one heaped scoop, and the scoop comes in the pack. You stir it into 100 to 150 ml of water or juice. A 200 g tub holds 200 servings. Capsules need no measuring and hold 250 mg to 650 mg each. If you take a larger amount every day, compare the price per day shown on each product card rather than the price of the pack.

How to take it

Take the dose on the label and do not exceed it. NOW Foods suggests taking its choline and inositol capsule with a meal. The other products give no time of day. Store the pack at room temperature or in a cool, dry place, out of reach of children.

Who should ask a doctor

NOW Foods labels say the products are for adults only and ask you to consult a doctor if you are pregnant, breastfeeding, have a medical condition or take medication. Swanson and OstroVit labels say the products are not recommended or not intended for pregnant or breastfeeding women, and OstroVit adds children.

Inositol benefits: what a shop may say

Inositol, and myo-inositol in particular, is widely discussed online, and many people search for its benefits before they buy. In the EU, a food supplement may carry only health claims that the European Commission has authorised and listed in the EU Register of nutrition and health claims. There is no authorised claim for inositol in that register. That means no shop may promise what it does in the body, and we do not. What we can tell you is checkable: the form on the label, milligrams per daily dose, whether choline is added and what the label warns about. The Croze and Soulage review under Sources describes where myo-inositol occurs in food, such as fruit, beans, grains and nuts, and how the body makes and uses it. If you are thinking about inositol for a specific reason, talk to your doctor first.

Questions

Is inositol vitamin B8?

Inositol is sometimes sold as vitamin B8, but it is not a vitamin in the EU sense. The body makes it itself, and it is not on the EU list of vitamins that may be added to food supplements as a vitamin. Labels in our range call it inositol or myo-inositol.

How do I take inositol powder?

Use the scoop in the OstroVit tub. One heaped scoop gives 1000 mg of myo-inositol. Stir it into 100 to 150 ml of water or juice and drink it straight away. Keep the lid closed so the powder stays dry.

When should I take inositol?

NOW Foods suggests taking its choline and inositol capsule with a meal. The other labels in this category give no time of day, so choose a time you can keep, for example with breakfast.

How long does the 200 g powder last?

With one 1000 mg serving a day, it lasts 200 days, as stated on the pack.

Sources

• Croze and Soulage, Biochimie 2013: review of myo-inositol sources and metabolism (PubMed)
• EU Register of nutrition and health claims
• EUR-Lex: Regulation (EU) No 432/2012 (permitted health claims)
• EFSA: Health claims

Content reviewed by Inese Kalniņa, dietitian.

2026-08-08