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Inositol supplements, myo-inositol and PCOS: your complete guide
Written byEmily Coates
Reviewed byHeeral Patel
Could inositol be the missing piece in PCOS management? Myo-inositol, the most active form, may help with blood sugar control, hormone balance and cycle regulation – but does the science stack up?
Summary
1Inositol, PCOS and fertility
Doctors and other healthcare professionals are increasingly suggesting myo-inositol for people with PCOS on a fertility journey...
2Can inositol help regulate periods?
There’s growing evidence that myo-inositol may help regulate menstrual cycles for those with PCOS. This is because...
3Inositol, insulin resistance and prediabetes
Myo-inositol may be helpful for those managing high blood sugar levels and dealing with insulin resistance, which is a key factor...
PCOS can be a rollercoaster of hormonal havoc, but could inositol help steady the ride? Myo-inositol, one of its most active forms, is gaining attention for its potential benefits in supporting blood sugar control and hormone balance – especially in women (and AFAB folk) with PCOS.1 2
Promising? Yes. Proven? While the science is still evolving, inositol is shaping up to be an interesting supplement worth watching. Time to break it down and separate fact from fiction.
What’s inositol?
Inositol might not be a household name, but this little sugar-alcohol is making waves in the wellness world. Scientifically, it's a molecule that exists in the body which supports cell function and helps maintain strong cell membranes. Simply put, it helps your cells communicate, balances hormones and influences metabolism.3,4 More on why this matters later.
Vitamin B8 is also a commonly used (but misleading) name for inositol.5 Despite the "vitamin" label, inositol isn’t actually a vitamin because the body can produce it naturally from glucose. Since true vitamins must come from your diet, inositol doesn’t make the official B list.
Where does inositol come from?
As well as being made in the human body, it’s also found in grains, legumes and even artichokes. Key food sources include wholegrains, nuts, seeds and soy products, with myo-inositol being particularly abundant in beans and citrus fruits.6
The form can vary depending on whether it comes from an animal or plant source. In plants, inositol is most abundant in the form of phytic acid, especially in foods like kidney beans, lentils and chickpeas.7 While rich in total inositol content, phytic acid is less bioavailable in the human body. In contrast, animal sources tend to contain lower amounts but in more readily absorbable forms like myo-inositol. Other forms you might have heard of are d-chiro-inositol and inositol hexaphosphate – but myo-inositol is the star here.
Why's myo-inositol so special?
Myo-inositol, the most biologically active form, may support blood sugar control, lower free testosterone levels and even help regulate menstrual cycles. While early research5 is encouraging (especially for those with insulin resistance), we’re not quite at a miracle cure just yet. Still, with more doctors providing information about inositol for PCOS and fertility support, it’s worth exploring what this little-known nutrient could bring to the table.8
How does inositol affect PCOS?
Inositol, especially the myo-inositol form, may support women with PCOS by tackling a few key troublemakers: high blood sugar, abnormal hormones and irregular cycles. Early evidence has shown to improve insulin sensitivity, which can help lower testosterone levels and, in turn, support more regular periods.9
While some studies show promise, overall the research is limited and more investigation is needed before saying for sure it helps with PCOS. Some studies also suggest that combining myo-inositol with metformin – a common medication for PCOS – may enhance cycle regularisation compared to taking metformin alone.
Inositol, PCOS and fertility
Doctors and other healthcare professionals are increasingly suggesting myo-inositol for people with PCOS on a fertility journey.8,10 It’s thought to potentially help with hormone balance and supporting ovulation in people with PCOS, which might increase the chances of conceiving in these patients.11
The link between myo-inositol and free testosterone
Myo-inositol may help reduce levels of free testosterone, which tend to be higher in people with PCOS.11 This hormonal shift can support ovulation and cycle regularity, making it a possible ally in hormone balance. It’s not a guaranteed fix, but studies suggest it might help dial things down naturally, especially when testosterone is throwing things off track.
Can inositol help regulate periods?
There’s growing evidence that myo-inositol may help regulate menstrual cycles for those with PCOS.
This is because it appears to support insulin sensitivity and lower testosterone – two big players when it comes to monthly cycle chaos.12-14
Inositol, insulin resistance and prediabetes
Myo-inositol may be helpful for those managing high blood sugar levels and dealing with insulin resistance, which is a key factor in prediabetes, type 2 diabetes and gestational diabetes. Though it’s still super important to continue with your prescribed medication and any advice given by your diabetes team.
A study suggested5,12 it may help improve insulin sensitivity and support better blood sugar control in people at risk. This is often monitored through the HbA1c blood test, which gives an average of your blood glucose levels over the past two to three months. Another looked into myo-inositol during pregnancy to help lower the risk of developing gestational diabetes.13 However, more research is needed, and it is important to speak to your doctor if you plan to take any supplements for the first time, especially during pregnancy.
Inositol and BMI: is there a connection?
A clinical trial found that myo-inositol supplementation led to a small but meaningful drop in BMI – particularly in those who are overweight or had PCOS.14 It’s no substitute for balanced eating and movement, but it might offer an extra nudge in the right direction for metabolism support in those who may need it.
The final say
Thinking about trying inositol? If you’re managing PCOS especially on a fertility journey, it could be worth a chat with your GP. While the research is still evolving, inositol might help support hormone balance, nudge your cycle back on track or work alongside diet and exercise to improve blood sugar levels and get that pesky HbA1c down.
Myo-inositol is the most biologically active form and shows the most promise, with studies asking participants to take between 2-4.5g a day.15-18 But while the science is growing, we’re not quite at “miracle supplement” status, and taking your prescribed medication is still super important.
Want to understand more? Keep reading to learn about the four types of PCOS and how low magnesium levels could be affecting your blood sugar.
This article provides informational advice and is not a substitute for medical care. Curated by experts for accuracy, we take great care to ensure the information is up-to-date and relevant. However, you should always consult your GP or healthcare professional before using supplements or alternative products, particularly if you have medical conditions or are under supervision.
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Available from: https://mft.nhs.uk/app/uploads/sites/4/2024/01/SMPIL-23-034-Polycystic-Ovary-syndrome-PCOS-PIL.pdf
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