Inositol
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No carbohydrate.
Fine for most people at normal amounts.
Rules by country
Inositol has no E-number and is not an additive, so it is sold as a supplement and a fortifier rather than under the additive rules. Health Canada lists it as a Schedule 1 isolate with no medicinal claim, allowing it for non-medicinal purposes such as a diluent and a cryoprotectant. A GRAS notice filed with the FDA treats it as safe in food at the levels used.
What is it?
Inositol is a six-carbon sugar ring with an alcohol group on every carbon, which makes it a polyol, though not one that sweetens anything. The body handles it separately from glucose, and it works inside the insulin signalling pathway. In a supplement it is dosed for that pathway, and the PCOS trials use 4 g a day, which is four of the 1 g sachets on the shelf. In food it turns up as a diluent and a cryoprotectant.
Where it comes from: Most inositol on a shelf is made by chemical synthesis, because it is a sugar ring that industry can make cheaply and consistently. Health Canada's ingredient database lists sources broken from Chlorella cells, from engineered E. coli, and from soy, rice and corn seeds.
Why it’s in food
- Supporting insulin signalling
- Studied for PCOS symptoms
- Working as a diluent
- Protecting food during freezing
Often found in
Also listed as: Inositol, Myo-inositol, Inositol (vitamin B8), myo-Inositol powder
Health & gut impact
Inositol is bought almost entirely for PCOS, and the trials do report better insulin sensitivity and more regular cycles for many women. What Health Canada allows is narrower, because its database lists inositol with no medicinal claim at all, only non-medicinal purposes such as a diluent and a cryoprotectant, which is the regulator's way of saying the evidence is not finished.
Health Canada, natural health products ingredients database
Health Canada's ingredient database lists inositol as an isolate that can be sourced from broken Chlorella cells, from engineered E. coli, or from the seeds of soy, rice and corn. So the sachet in your hand may be fermentation or synthesis rather than a plain plant extract, and the source is the line to read.
Health Canada, natural health products ingredients database
A GRAS notice filed with the FDA treats inositol as safe for use in food and in supplements at the levels people take it. The safety work behind that notice could not set a maximum daily amount, because the available data did not support one, so the 4 g a day sold for PCOS is a choice rather than a limit.
FDA, Generally Recognized as Safe (GRAS) determination for inositol
What can I use instead?
Related
More functional ingredients:
Common questions
Is inositol the same as vitamin B8?
It is sold as vitamin B8, but it is not a vitamin in the sense that you need a fixed amount from food, and there is no recommended intake for it. It is a sugar-like molecule your body makes and uses inside insulin signalling, and your liver makes plenty of it.
Does inositol work for PCOS?
The trials look promising for insulin sensitivity and cycle regularity, but the regulator has not signed off on it as a treatment. Health Canada's database lists no medicinal claim for inositol, so read the studies as encouraging rather than settled.
How much inositol should I take?
The dose used in the larger PCOS trials is 4 g a day, which is one 4 g sachet or four 1 g ones. Health Canada sets no maximum daily amount for it, and the evidence is thin at doses well above that, so more is not obviously better.
Is inositol safe to take long term?
It is one of the better studied supplements for safety, and a GRAS notice treats it as safe in food. Several grams at once can cause stomach discomfort and headache, and if your kidneys are not working well, check with a doctor first because inositol is cleared through them.
Is Inositol safe?
Generally safe (88/100). Inositol has no E-number and is not an additive, so it is sold as a supplement and a fortifier rather than under the additive rules. Health Canada lists it as a Schedule 1 isolate with no medicinal claim, allowing it for non-medicinal purposes such as a diluent and a cryoprotectant. A GRAS notice filed with the FDA treats it as safe in food at the levels used.
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Scientific sources & regulatory citations
- Health Canada, natural health products ingredients database
- FDA, Generally Recognized as Safe (GRAS) determination for inositol
CAS 87-78-5