What is Inositol?
Inositol is a type of sugar that is naturally produced in the body. It is primarily stored in the brain and other tissues. The body synthesises approximately 2 grams of inositol per day, but it can also be obtained from carbohydrate-rich foods such as grains, nuts, and fruits. In recent years, supplementation has become an increasingly popular topic of interest. There are nine different forms of inositol, but myo-inositol (MI) and D-chiro-inositol (DCI) are considered the most effective supplemental forms.
This article aims to explain more about the roles of inositol in the body and the benefits of supplementation in the management of a variety of health conditions.
The Many Roles of Inositol in the Body
Inositols are linked to a number of important functions in the body. Their primary role is in mediating cell signal transduction in response to various hormones, neurotransmitters, and growth factors. Some of the many functions and benefits of inositol include:
- Improving insulin sensitivity, which can be a helpful management strategy that is important for those with insulin resistance.
- Assisting in regulating hormonal signalling in polycystic ovary syndrome (PCOS), which may improve its associated metabolic side effect such as blood lipid profiles and hormonal side effects such as hyperandrogegism.
- Supporting the production of neurotransmitters such as dopamine and serotonin – which are linked to many mental health conditions including anxiety and depression.
- Involved in the regulation of follicle-stimulating hormone (FSH), which can improve egg quality and ovulation, therefore improving fertility outcomes.
Supplementation – When Would It Be Useful?
A recommended dietary intake (RDI) has not been established for inositol; however, low doses of 2–4 grams per day are generally well tolerated. A supplementation protocol can help ensure adequate intake, in addition to the typical dietary intake of around 1 gram per day. Conditions such as polycystic ovary syndrome (PCOS), metabolic syndrome, gestational diabetes, and mood disorders may benefit from supplementation, as these conditions are frequently associated with lower inositol levels. Therefore, correcting potential deficiencies through supplementation may help reduce symptoms related to these health conditions.
Studies in these areas have shown benefits in utilising the following supplement protocols:
Inositol & polycystic ovary syndrome: 2g of MI and 200 mcg of folic acid twice daily for 6 months, led to reduced insulin resistance, decrease in body weight, and improvement in ovarian function in people with PCOS.
Inositol & metabolic syndrome: 2g of MI twice daily for one year alongside a calorie-restricted diet, led to a significant improvement in markers of metabolic syndrome. In the study featuring 40 women with metabolic syndrome, 8 women in the group taking MI no longer met the criteria for metabolic syndrome after the completion of the study, compared to just one woman in the control group.
Inositol & gestational diabetes: 2g of MI and 400 mcg of folic acid twice daily during pregnancy have been shown to reduce the risk of gestational diabetes by 13.5% compared to 6% in the control group in a study of 2,000+ women.
Inositol & mood disorders: 12–18 grams of MI once daily for 4–6 weeks, saw an overall improvement in scores on the Hamilton Depression Rating Scale, as well as the Hamilton Rating Scale for Anxiety scores, agoraphobia scores, and Clinical Global Impressions Scale scores, were significantly greater for inositol than the placebo.
Simplified Supplement Approach
Most conditions will benefit from 2g of inositol twice daily through supplementation. This protocol is relatively inexpensive and easy to follow.
However, a randomised control study has shown that the combined supplementation of MI and DCI was shown to be more effective compared to the MI supplementation-only group, after three months of treatment. This protocol involves supplementing with a 40:1 ratio of MI:DCI – this would be the equivalent of 2000mg Myo-inositol and 50mg Di-chiro inositol twice daily. This protocol is more effective, however, the supplements themselves are slightly more expensive. An example could be this one.
One outlier to these lower-dose protocols is supplementing for the management of mood disorders, where up to 18mg of inositol per day has shown benefits although, this is best done under the guidance of your healthcare team.
Potential Side Effects
Mild side effects have been reported with high doses of >12 grams per day, which is only recommended for those looking to manage mood disorders. The symptoms of which do include headache, dizziness, tiredness, nausea, gas and difficulty sleeping.
In addition, long-term supplementation has not been studied, and therefore there is no data to determine the safety of long-term use.
Final Thoughts
If you’re reading this, you’re probably interested in inositol supplementation. If you are seeking additional support to help manage any of the previously mentioned conditions, a three-month trial of inositol supplementation may be beneficial. Be sure to discuss the use of these supplements with your GP or other relevant healthcare providers first, to ensure you find the correct form and dosage for your individual needs.
