Have you ever heard of myo-inositol (MI)?
Well, if you currently suffer with Polycystic Ovarian Syndrome (PCOS) or, if you’re interested in supporting your fertility, you’ll want to read this!
Experiencing fertility issues can often leave you feeling frustrated, even hopeless at times. For women who have been diagnosed with a hormonal condition, such as PCOS, the struggles can feel exponential.
You may find that you have to work even harder to regulate your menstrual cycle, control your weight, maintain blood sugar balance and minimize your androgen levels; all of which are critical for optimizing fertility levels.
While implementing a fertility promoting routine, diet and lifestyle are foundational pieces to the fertility puzzle. Additionally, a little extra nutritional support can go a long way in helping you to achieve your fertility goals.
This is where supplements come into play.
What is myo-inositol and how does it support fertility?
MI belongs to the B-complex family of vitamins. While commonly referred to as ‘B8’, it is not officially recognised as a vitamin due to the way it is synthesized. Interestingly, MI is synthesized from glucose by the bacteria within our intestines, making it unique in comparison to regular B vitamins (1).
There are two forms of inositol which have been investigated in regards to the effects on fertility: MI and d-chiro-inositol (DCI); however, studies suggest that the MI form of inositol might be the most effective when it comes to fertility and egg quality (2).
It has been discovered that women who struggle with infertility or PCOS often have an imbalance of MI and DCI, which is why these compounds have been widely researched for their role in fertility. MI has been found to modulate the activity of the follicle stimulating hormone (FSH); a key factor in hormonal regulation and the egg release cycle (3).
Additionally, in women with PCOS, MI demonstrated significant improvements in insulin sensitivity and the promotion of lean body mass (4).
How can myo-inositol help PCOS?
PCOS is an increasingly prevalent hormonal condition that is believed to affect as many as 1 in 5 women of childbearing age (5). It is characterized by an excess in circulating androgens (namely testosterone and DHEA), as well as abnormalities in glucose metabolism such as reduced insulin resistance and elevated fasting blood glucose (6). Combined, these imbalances can result in difficulties with losing weight, skin hyperpigmentation and impaired fertility (7,8).
Within the presentation of PCOS, it is believed that insulin sensitivities precede the elevated testosterone levels and reduced fertility, which is why insulin sensitizing drugs are often the
the first line of treatment for women with this condition (9). However, as the urinary output of inositol metabolites is often impaired in both diabetics and women with PCOS (10), MI supplementation is now being widely investigated for its role in supporting insulin sensitivity.
As we know, the main concerns with PCOS are issues with elevated testosterone and impaired insulin response (8), which are exactly the areas where MI appears to deliver most of its benefits.
In a study investigating the effects of MI on twenty six normal weight women over a 12 week period, MI showed to be effective at reducing hormonal, metabolic and oxidative abnormalities such as elevated testosterone and insulin sensitivity in women with PCOS versus placebo (11). A similar study discovered that this action of MI on insulin resistance may be even more effective in women with PCOS who are overweight (12).
Myo-inositol and PCOS: what does the research show?
By far one of the most highly researched areas regarding the therapeutic application of MI is in its effect on women with PCOS. Within this demographic, MI has shown most promise through its actions on insulin sensitivity and androgen metabolism.
Researchers have discovered that imbalances in MI and DCI can lead to dysregulations in the metabolism of sugar within the body (13). MI and DCI demonstrated insulin-like properties, supporting a more optimal blood sugar balance in patients with PCOS. Furthermore, these compounds were involved in increasing the insulin sensitivity of various tissues to improve metabolic and ovulatory functions (7,9).
While both MI and DCI appear to play a role in the insulin pathway, MI may be more important when it comes to cases of PCOS and insulin resistance.
In 2014, it was discovered that women suffering from PCOS who also had excess circulating insulin (hyperinsulinemia) showed an increase in their MI to DCI conversion within the ovary. This resulted in MI deficiencies which could potentially impair FSH signalling, resulting in reduced egg quality (14).
For this reason, researchers believe that supplementation with the MI form of inositol specifically could help to regulate this imbalance in women suffering with PCOS.
Additionally, in 2015, further support was found by a study which demonstrated the ability of the ovaries to convert MI to DCI when the body is dealing with insulin resistance; in an effort to control blood sugar imbalances. Overtime, this can lead to the overproduction of DCI and the depletion of MI in women with insulin resistance such as in the case of PCOS (15).
As we have discovered, MI supplementation in women with PCOS improves insulin sensitivity and reduces insulin levels, however clinical studies have also demonstrated its ability to decrease serum androgen levels (male hormones which are often elevated in women with PCOS) (16).
A meta-analysis of MI studies conducted in women with PCOS demonstrated a reduction in overall testosterone concentrations by MI versus controls (17). Additionally, subjects assigned 24 weeks of MI supplementation demonstrated a significant increase in sex hormone binding globulin (SHBG); a protein which is required for the safe passage of the key sex hormones oestrogen, testosterone and dihydrotestosterone (DHT) throughout the body (19).
As a decrease in SHBG levels is often observed in women with PCOS, MI could be helpful in rebalancing these levels. Furthermore, low SHBG levels have been indicated in the recurrence of miscarriages (18), insulin resistance and an increased risk of developing diabetes (19).
Myo-inositol and Egg Quality
MI has long been known for its important role in cellular health, fat metabolism and chemical messaging throughout the body (20).
More recently, MI has been discovered as a critical component of follicular fluid, while also playing a role in healthy follicle development (21). Additionally, MI may enhance insulin sensitivity in the ovary, encouraging improved egg quality (22). This effect may be particularly supportive in women who have issues with insulin resistance, blood sugar balance or PCOS where egg quality can be affected (23).
MI appears to be repeatedly evidenced as the superior choice to DCI. One study published in the European Review for Medical and Pharmacological Sciences, which discovered that MI, rather than DCI, was better able to improve egg and embryo quality in women with PCOS (2). These results were further supported by a study which demonstrated improved egg quality and restored menstrual cycles in women who supplemented with 2,000mg of MI twice per day (4).
Myo-inositol and Pregnancy
Evidence suggests that MI supplementation may even further protect against the incidence of gestational diabetes (GD) (24).
During pregnancy, diabetogenic hormones are produced by the placenta in order to provide a reserve of energy for the foetus; in case changes to nutritional status were to occur. This results in a temporary state of increased insulin resistance in the body, which is managed by the mother’s insulin response (25). In normal pregnancies, this is enough to keep the blood sugars within a healthy range however, in the case of PCOS or other issues with insulin sensitivity, the body cannot respond with sufficient insulin. This issue is why women with PCOS, increased body mass or a family history of diabetes are often deemed as high risk for developing GD.
For this reason, these women are often encouraged to use insulin-sensitizing medications such as metformin during pregnancy in order to control their blood sugar balance and reduce their risk of developing GD and associated factors (9).
Interestingly, it has been demonstrated that women with GD tend to excrete high levels of inositol in their urine during pregnancy (26). Therefore, researchers have been investigating the benefits of MI supplementation for this group of women.
An Italian study published in the Journal of Obstetrics and Gynaecology revealed a 66% reduction in the occurrence of GD in obese women (BMI of 30 or more)(27) supplementing with a combination of MI (2,000mg) and folic acid (200mcg) twice daily over the course of their pregnancy. In this study, MI supplementation began in the first trimester and continued until delivery. In line with previous studies, researchers believe that this reduction may be due to the particular ability of MI to reduce insulin sensitivity (12).
Additionally, in 2015, these results were further supported when it was found that MI reduced the rate of GD in a group of overweight women (BMI 25-30) by 15.8% when compared with the placebo group (28).
Lastly, MI supplementation may also be effective in early pregnancy for those experiencing elevated fasting glucose levels. In a group of thirty-six non-obese women, those who took MI required less insulin therapy, gave birth at a later gestational age and had significantly less incidences of babies being delivered with hypoglycaemia or low blood sugar (29).
Myo-inositol and IVF
While the majority of research for MI supplementation in fertility has focused on PCOS and egg quality under regular conditions, a number of studies have applied this treatment to IVF patients in the hopes that it would aid women on their journey to conception.
Studies have found that women undergoing IVF treatment who didn’t have PCOS demonstrated a reduction in the amount of FSH administered as well as a reduction in the total number of mature oocytes obtained, however no changes in rates of pregnancy occurred following supplementation MI and folic acid daily (30). Interestingly, similar results were obtained in women undergoing IVF treatment who had PCOS, however trends did suggest an improvement in pregnancy rates (31).
While a standard pre-treatment time for MI supplementation has yet to be established in IVF patients, the majority of studies began supplementation between 1-3 months prior to the start of the IVF cycle.
Where can I find myo-inositol?
Now that you’ve seen the growing pool of evidence on MI, the important part is how can you incorporate it into your routine and perhaps reap the benefit of MI on PCOS and fertility.
Although inositol is synthesized within the body, it is important that you also obtain it from external sources in order to meet your requirements. Both forms of inositol (MI and DCI) are found in a range of foods, however the largest amount of MI is available in fresh fruits and vegetables (32) – not their canned or frozen counterparts!
Some good options for increasing MI intake include:
- Leafy green vegetables
- Whole grains
That being said, when looking to use MI in support of PCOS and fertility, it can be difficult to achieve optimal daily doses through food alone.
In this case, you may consider supplementation in order to obtain the therapeutic doses used in research studies. The majority of studies discussed used between 1,000mg and 4,000mg of MI daily (11,12,4), which can be a tough number to meet through diet alone!
It should also be noted that many studies showed an increase in the benefits obtained when MI was taken in conjunction with folic acid, which might be a consideration if you are interested in boosting fertility.
Are there any side-effects to consider when supplementing with myo-inositol?
According to available research, MI has been deemed as a very safe supplement, particularly in the doses recommended for PCOS and insulin resistance (33).
With that being said, it is recommended to speak with your doctor or healthcare professional before taking any new supplement when trying to conceive.
As you can see, MI supplementation is fast becoming a large part of clinical practice in supporting fertility, PCOS and IVF treatments. This new breakthrough is demonstrating a clear role in its ability to promote hormonal balance, restore insulin sensitivity and support healthy egg quality.
With such exciting potential in the future of hormonal support and PCOS treatment, MI may be a great first-line option for those looking to naturally enhance their fertility.
This article was written and researched by Anita Tee. Anita is a published nutritional scientist carrying a Master of Science in Personalised Nutrition and a Bachelor of Science focussed in Genetic & Molecular Biology. Anita is the founder of www.factvsfitness.com, which focuses on an allergy-mimicing disorder called histamine intolerance. Find out more about Anita by following her on Twitter Instagram or Facebook.
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