Inositol is a naturally occurring compound, sometimes grouped with the B vitamins, that your body makes on its own and also gets from food. It is commonly used to support insulin sensitivity, mood, and aspects of women's health.
This guide covers what inositol is, what the evidence supports, the two main forms, typical use, and safety. It is general information only, so speak to your doctor before starting inositol, especially if you have a health condition.
Key points
- A natural compound. Your body makes inositol and you also get it from everyday foods.
- Commonly used to support. People take it for insulin sensitivity, mood, and women's health.
- Two main forms. Myo-inositol and D-chiro-inositol, often combined in a set ratio.
- Popular with PCOS in mind. It is widely used by women managing PCOS, alongside medical advice.
- Talk to your doctor first. Especially if you are pregnant, trying to conceive, or on medication.
What is inositol?
Inositol is a sugar-like compound found naturally in the body and in many foods. It is sometimes referred to as vitamin B8, although it is not strictly a vitamin because your body can make it on its own (Cleveland Clinic; Bizzarri et al., 2018). It plays a role in how cells respond to signals, including the way your cells respond to insulin (Bizzarri et al., 2018).
You get inositol from a normal diet as well. It is found in foods such as fruits, beans, grains, and nuts (DiNicolantonio & O'Keefe, 2022). Supplements simply provide it in a more concentrated, measured form.
Where inositol comes from
Your body produces inositol, and you also absorb it from food (Bizzarri et al., 2018). Because it is water soluble, it is not stored in large amounts, which is part of why some people choose to supplement it.
What are the benefits of inositol?
Inositol is commonly used to support insulin sensitivity, mood, and certain aspects of women's reproductive health. The strongest interest sits around its role in how the body handles insulin (Facchinetti et al., 2016).
Because the evidence varies by use, it is best thought of as a supportive supplement rather than a fix. What people commonly use inositol for includes:
- Insulin sensitivity. It may support the way cells respond to insulin (Facchinetti et al., 2016).
- Mood and anxiety. It is commonly used to support mood, though the best available research found no significant effect (Mukai et al., 2014).
- Women's health. It is widely used by women managing PCOS, discussed in the next section (DiNicolantonio & O'Keefe, 2022).
- Sleep. Some people take it in the evening as part of a wind-down routine.
Explore the range on the inositol supplements hub, led by house brand Emrald Labs Inositol.
Is inositol good for PCOS?
Inositol is one of the most commonly used supplements among women managing polycystic ovary syndrome (PCOS). Interest centres on its role in insulin sensitivity, which is relevant because insulin resistance is common in PCOS (DiNicolantonio & O'Keefe, 2022).
Research has looked at inositol, and myo-inositol in particular, for supporting metabolic and hormonal markers in women with PCOS (DiNicolantonio & O'Keefe, 2022). The results are promising but the picture is still developing, so it should be viewed as a possible support alongside proper medical care, not a replacement for it.
Important: PCOS is a medical condition that needs proper diagnosis and management. If you have PCOS, are trying to conceive, are pregnant or breastfeeding, or take any medication, speak to your doctor before starting inositol. It is not a substitute for prescribed treatment.
How much inositol should you take?
There is no single official dose of inositol, and the right amount depends on the person and the reason for taking it. Studies in women's health have often used a total of around 4 grams of myo-inositol per day, frequently split into two doses (DiNicolantonio & O'Keefe, 2022).
Many myo-inositol and D-chiro-inositol products use a set ratio between the two forms, which is covered in the final section (Nordio et al., 2019). Because the ideal amount varies, it is sensible to follow the label on your product and to check with your doctor or pharmacist, particularly if you take other supplements or medication.
How people take it
Inositol powder mixes into water or a drink, and capsules are an alternative if you prefer not to mix a powder. Some people split the daily amount across the day, and some take a portion in the evening.
Is inositol safe, and are there any side effects?
Inositol is generally well tolerated in healthy adults, and reported side effects are usually mild (Carlomagno & Unfer, 2011). At higher amounts, some people notice digestive upset such as nausea or loose stools (Carlomagno & Unfer, 2011).
Safety in specific situations is less certain, so caution matters more than usual if any of the following apply to you:
- Pregnant or breastfeeding. Speak to your doctor before use.
- Trying to conceive. Get medical advice first, as this is a sensitive time.
- On medication. Check for interactions with your doctor or pharmacist, especially diabetes medication, as inositol can act on blood glucose (Facchinetti et al., 2016).
- Have a health condition. Discuss it with your GP before starting.
If you notice any reaction that concerns you, stop taking it and speak to a health professional.
What is the difference between myo-inositol and D-chiro-inositol?
Myo-inositol and D-chiro-inositol are the two forms of inositol used in supplements. Both occur naturally in the body, and they carry out related but different roles in how cells respond to insulin (Facchinetti et al., 2016).
Myo-inositol is the most abundant form in the body and is the one most studied for women's health (Facchinetti et al., 2016). D-chiro-inositol is present in smaller amounts. Many products combine the two, and a commonly used ratio is 40 to 1 in favour of myo-inositol, chosen to reflect the balance the body naturally maintains (Facchinetti et al., 2016; Nordio et al., 2019).
Which form to choose
Most people looking at inositol for the reasons above choose a myo-inositol product, or a combined myo and D-chiro formula at a set ratio. Compare the options on the inositol supplements hub. Elite stocks house brand Emrald Labs Inositol as well as Switch Inositol.
Related reading
References
- Cleveland Clinic. Inositol. Cleveland Clinic health library. https://my.clevelandclinic.org/health/drugs/25173-inositol
- Bizzarri M, et al. Inositols in Insulin Signaling and Glucose Metabolism. International Journal of Endocrinology, 2018. https://pmc.ncbi.nlm.nih.gov/articles/PMC6286734/
- DiNicolantonio JJ, O'Keefe JH. Myo-inositol for insulin resistance, metabolic syndrome, polycystic ovary syndrome and gestational diabetes. Open Heart, 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC8896029/
- Facchinetti F, et al. Inositols in the Treatment of Insulin-Mediated Diseases. International Journal of Endocrinology, 2016. https://pmc.ncbi.nlm.nih.gov/articles/PMC5027050/
- Mukai T, et al. A meta-analysis of inositol for depression and anxiety disorders. Human Psychopharmacology, 2014 (NCBI Bookshelf, NBK184852). https://www.ncbi.nlm.nih.gov/books/NBK184852/
- Carlomagno G, Unfer V. Inositol safety: clinical evidences. European Review for Medical and Pharmacological Sciences, 2011. https://pubmed.ncbi.nlm.nih.gov/21845803/
- Nordio M, et al. Study of the 40:1 myo-inositol to D-chiro-inositol ratio in PCOS. European Review for Medical and Pharmacological Sciences, 2019. https://pubmed.ncbi.nlm.nih.gov/31298405/
This article is general information only and is not medical or personal health advice. Inositol supplements are intended for healthy adults. If you are pregnant, breastfeeding, trying to conceive, under 18, have a health condition such as PCOS, or take regular medication, speak with your GP before starting inositol or any new supplement.
