Inositol For Treating PCOS – Things You Should Know

Inositol is a supplement that is very effective at treating polycystic ovary syndrome. Find out how it works and what type of inositol supplement to choose if you are suffering from PCOS.

What is Inositol

Inositol is a nutritional supplement that people take for a range of medical conditions. It is considered a vitamin-like substance and was in the past characterized as one of the B vitamins.

Inositol is commonly used by women who suffer from polycystic ovary syndrome. It is also used for managing blood sugar levels, for treating mental health conditions (such as depression, anxiety, OCD and panic disorder), and even, together with its derivative IP6, as an anti-cancer substance.

Polycstic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder. The signs of PCOS include irregular or absent menstruation, weight gain or inability to lose weight, acne, excess body hair and sometimes male pattern baldness. During an ultrasound exam, physician can observe enlarged ovaries with multiple small cysts (follicles).  

Causes of polycystic ovary syndrome are not well understood. However, there is a broad consensus that insulin resistance precedes all other metabolic problems and hormonal imbalances caused by PCOS.

So, let’s explain shortly what insulin resistance actually is. After a meal, the level of glucose in our blood rises. This triggers the pancreas to secrete insulin, which drives the glucose from our blood into our body tissues to be used as fuel for our cells.

When we become insulin resistant, our cells don’t respond normally to the circulating insulin, which causes high blood sugar levels. As a result, pancreas increases insulin production, which may in the long term lead to metabolic syndrome and type 2 diabetes.

How Does Inositol Work For PCOS (Polycistic Ovary Syndrome)

It has been shown that women with PCOS excrete more inositol in their urine than women without this condition - so in a way, they suffer from inositol deficiency. That is why it has been proposed that taking inositol supplements might be of benefit to PCOS patients.

Since then, inositol has been extensively studied for its use in treating PCOS.  And studies have shown that it has remarkable results on the different symptoms of this condition (1).

Let’s take a closer look at how and why inositol helps polycystic ovary syndrome.

Inositol Increases Insulin Sensitivity

Insulin resistance is at the root of PCOS and all other imbalances seen in PCOS originate from it.

Inositol is a well known insulin sensitizer, which means that it improves how our cells respond to insulin. It is not a coincidence that prescription medication for PCOS – Metformin - is also a type of insulin sensitizer.

Studies have shown that supplementing with inositol corrects the imbalances in insulin signaling and alleviates insulin resistance (2).

Inositol Induces Ovulation and Restores Menstrual Cycles

Several studies have shown that insoitol supplementation improves ovarian function and normalizes menstrual cycles (2), (3).

Women with PCOS have extremely high levels of luteinizing hormone (LH) in their blood.  This is the hormone that triggers ovulation. For ovulation to happen, the body needs to experience the so-called LH surge (acute rise of LH). Since women with PCOS consistently have high levels of LH, the surge doesn't happen and consequently there is no ovulation.

Inositol has been shown to decrease the levels of LH in PCOS women and help induce ovulation (4), (5).

In one study, (6) researchers compared how inositol and metformin work for the induction of ovulation. Inositol at 4 grams daily has been shown to outperform 1.500 mg of metformin (50% of women on mentformin achieved spontaneous ovulation as opposed to 65% of women who were receiving inositol). 

Inositol Lowers Circulating Androgens

Women with PCOS have increased levels of androgens in their body (male sex hormones, such as testosterone). This commonly causes excess body hair (hirsutism), acne and, in some cases, male pattern baldness.

Inositol supplementation has been shown to help decrease androgen levels and the associated physical signs (7).

Decreases Systemic Inflammation Related to PCOS

PCOS causes low level inflammation throughout the body.

A 2012 study (8) has shown that taking inositol supplements (at a dose of 1.2 g per day) was able to reduce systemic inflammation (as measured by reactive oxygen species in red blood cells).

Inositol May help Weight Loss or Prevent Weight Gain Caused by PCOS

PCOS often results in weight gain. And even if a woman with PCOS tries to lose weight, she finds it increasingly difficult.

Inositol has been shown (9) to help women lose weight or at least prevent them for gaining any additional weight. There are 2 main reasons for that.

First one is the fact that inositol addresses insulin resistance. When you are insulin resistant, the glucose in your blood is stored as fat instead of being used as a fuel for your cells.  So, insulin resistance is one of the major factors of weight gain.

Inositol also contributes to better mood. This in turn helps women alleviate emotional overeating and reduces cravings for junk food. 

Inositol Boosts Egg Quality and Increases the Chances of Getting Pregnant

High levels of inositol in the ovaries support healthy development and maturation of follicles. Several studies have shown that inositol improves both egg cell and embryo quality and increases the rate of pregnancy in PCOS women (10), (11) – in this study, inositol was taken together with alpha lipoic acid, which has been shown to boosts its effects).

Inositol Lifts Mood and Helps With Depression and Anxiety

Among other things, inositol also has a beneficial effect on our brain. It raises the level of the neurotransmitter (chemical messenger) serotonin, which is involved in our sense of wellbeing and happiness.

That is why inositol may help those women with PCOS that suffer from anxiety, depression, OCD or panic disorder. However, it needs to be noted that the dose required for the effect on mood and mental health (12 to 18 grams daily) is a lot higher than the dose needed for managing the symptoms of PCOS.

Which Type of Inositol to Use for PCOS: Myo vs D-Chiro Inositol

Myo-inositol is the type of inositol, which is generally found in supplements (it is usually made from rice bran). In fact, if the supplement doesn’t have a type of inositol specified on the label, you can be fairly certain that it contains myo-inositol.

D-chiro inositol is much less common. It is made from carob extract and is a lot more expensive than myo-inositol.

Most women with PCOS take myo-inositol supplement. Myo-inositol has also been extensively studied for its use in treating the symptoms of PCOS and it has been proven to be very effective.

There were several studies, though, that examined the effect of myo-inositol and d-chiro inositol, taken together. These studies indicate that the combination of the 2 inositols might work even better for PCOS (12), (13).

So, which one to take?

If you want to take inositol for balancing menstrual cycles and inducing ovulation, both options seem to work well. The same goes for improving egg quality – both myo-inositol alone as well as the combination of myo and d-chiro inositol seem to improve egg quality and increase pregnancy rates

The combination of the 2 inositols appears to be best suited for overweight and obese women with PCOS. In this group of women, the combination has been shown to be more effective at improving insulin sensitivity and decreasing blood lipids.

A word of warning… Don’t take d-chiro inositol alone, especially if you plan to take the supplement for increasing fertility. Studies have shown that d-chiro inositol – when taken alone and in sufficiently high doses – actually decreases the quality of egg cells and reduces your chance of healthy pregnancy.

How to Take Inositol for PCOS

Inositol PCOS Dosage

You can decide to take either myo-inositol alone or myo-inositol in combination with d-chiro inositol.

The dosage for myo-inositol is usually between 2 grams and 4 grams daily.  Most often women use the higher dose (4 grams), which also seems to be more effective. It is important to note that inositol is water-soluble, so it can’t reach potentially dangerous concentrations in the body with time.

If you decide to take the combination of the 2 inositols, their ratio needs to be 40:1, which is their ratio in human body.

The dose use in studies has been 1.1 g myo-inositol plus 27.6 mg of d-chiro-inositol. Most supplements provide higher doses, but they stick to the physiological ratio of the 2 inositols (40:1).

Taking Inositol Supplement

Inositol supplements are usually very well tolerated. Common side effects include diarrhea, upset stomach and sometimes nausea. The risk of side effects increases with higher doses. That is why it is important to start slowly and increase your dose with time, so your body can get used to the new supplement.

Inositol is typically taken in bulk powder form.  The reason for this is that taking therapeutic dose of inositol (4 grams daily) in capsules is inconvenient and fairly expensive (you would need to take 8 capsules at 500 mgs each to reach the required daily dose).

Inositol powder is a cost-effective option of taking inositol supplements. Inositol powder is finely ground, white powder, which is easily dissolved in water or juice. It has a mild, slightly sweet taste.

It is always best to take inositol on an empty stomach to maximize absorption. If you take 4 grams, divide the dose in two and take half of it in the morning and half in the evening.  Alternatively, you can take your whole daily dose of inositol in the morning before breakfast.

Some authors propose that you wait a while between taking inositol supplement and drinking coffee as there have been some indications that caffeine inhibits the action of inositol (especially its action on the nervous system – important for those who take inositol for its benefits to the brain and mental health).

It takes a while for the body to respond to inositol supplementation, so wait a while before you asses if inositol works for you or not.

Recommended Inositol Supplements for PCOS

In this section, we’ll review 3 popular inositol supplements that are often taken for treating PCOS.

First two supplements contain only myo-inositol, while the third one contains a combination of myo and d-chiro inositol. Each of these supplements has its own pros and cons. We’ll go through them one at a time.

Jarrow Formulas Inositol Powder

Jarrow Formulas inositol powder is pure myo-inositol, without any other ingredients. This powder is made from rice bran and is suitable for both vegans and vegetarians.

Jarrow Formulas inositol powder is among the most popular inositol supplements on the market. It comes from a reputable manufacter that has an extensive internal testing program. These tests ensure that each supplement that you get is free from heavy metal and microbial contamination and contains the active ingredient – inositol – at the dose stated on the label.

 A teaspoon of Jarrow Formulas inositol powder provides 2.4 grams of inositol.

This is myo-inositol powder, so the recommended daily dose is between 2 and 4 grams daily (doses towards the higher end seems to work better). If you aim for 4 grams, you should be taking slightly less than 2 teaspoons daily.

Jarrow formulas inositol is a solid choice if you plan on taking inositol in its bulk powder form.

Get more info and read customer reviews on Amazon: Jarrow Formulas Inositol Powder


Pregnitude contains myo-inositol and folic acid, packaged together in convenient little packets.

The product is primarily intended for those women with PCOS who are trying to get pregnant. The reason why Pregnitude contains folic acid is that folate has been shown to prevent neural tube defects in developing embryo.

Each packet of Pregnitude contains 2 grams of inositol and 200mcg of colic acid. The recommended dose is 2 packets daily, which amounts to 4 grams of inositol and 400mcg of folic acid.

However, there is a slight problem with this supplement. Namely, Pregnitude contains the synthetic version of folate – folic acid.

If you are trying to get pregnant, it would be more sensible to get the form of folate, called l-methylfolate. This is the bioavailable form of folate, which means that it is readily used by our body.

On the other hand, each time you ingest folic acid, it needs to be first converted into l-methylfolate so our body can use it. Also, some women have impaired action of the MTHFR enzyme that is needed for this conversion, so even if they take a folic acid supplement, their blood levels of folate are low (14).

Taking the right form of folate is especially important for women who have had previous pregnancy with nuchal tube defect or preterm birth (or have a confirmed mutation of the MTHFR enzyme).

That is why it is better to skip Pregnitude and get inositol and folate in 2 separate supplements (aim for at least 400mcg of folate daily).  Jarrow inositol powder is a good option for inositol and you can find a range of l-methylfolate supplements on Amazon. Last, but not least, this will probably also be cheaper than getting Pregnitude. 

Get more info and read customer reviews on Amazon: Pregnitude


Ovasitol is one of the rare supplements that contain myo-inositol and d-chiro inositol in their ideal ratio 40:1.

It is in powder form and packaged into packets that you can simply put in your purse and take along. Daily serving is 2 packets, which provide together 4 grams of myo-inositol and 100 mg of d-chiro inositol.   

Besides the 2 inositols, Ovasitol also contains maltodextrin, which is used as a thickener. Maltodextrin may cause diarrhea or constipation in sensitive people. If this happens, try another inositol supplement before you stop using inositol altogether.

Ovasitol is worth a try, especially if you have excess weight and other related metabolic imbalances (increased blood lipids, severe insulin resistance).  The reason for this is that the combination of myo and d-chiro inositol has been shown to be especially effective for overweight and obese women with PCOS – in this group of women, combination tends to show better results than taking myo-inositol alone. 

Get more info and read customer reviews on Amazon: Ovasitol

  1. Vittorio Unfer et al. Effects of Inositol(s) in Women with PCOS: A Systematic Review of Randomized Controlled Trials. (2016)
  2. Antonio Simone Laganà et al. Metabolism and Ovarian Function in PCOS Women: A Therapeutic Approach with Inositols. (2016)
  3. Gerli S et al. Randomized, double blind placebo-controlled trial: effects of myo-inositol on ovarian function and metabolic factors in women with PCOS. (2007)
  4. Genazzani AD et al. Myo-inositol modulates insulin and luteinizing hormone secretion in normal weight patients with polycystic ovary syndrome. (2014)
  5. Artini PG et al. Endocrine and clinical effects of myo-inositol administration in polycystic ovary syndrome. A randomized study. (2013)
  6. Raffone E et al. Insulin sensitiser agents alone and in co-treatment with r-FSH for ovulation induction in PCOS women. (2010)
  7. Minozzi M et al. Treatment of hirsutism with myo-inositol: a prospective clinical study. (2008)
  8. Donà G et al. Inositol administration reduces oxidative stress in erythrocytes of patients with polycystic ovary syndrome. (2012)
  9. Gerli S et al. Randomized, double blind placebo-controlled trial: effects of myo-inositol on ovarian function and metabolic factors in women with PCOS. (2007)
  10. Deepika Garg and Reshef Tal. Inositol Treatment and ART Outcomes in Women with PCOS. (2016)
  11. Rago R et al. Effect of myo-inositol and alpha-lipoic acid on oocyte quality in polycystic ovary syndrome non-obese women undergoing in vitro fertilization: a pilot study. (2015)
  12. Monastra G et al. Combining treatment with myo-inositol and D-chiro-inositol (40:1) is effective in restoring ovary function and metabolic balance in PCOS patients. (2016)
  13. Nordio M and Proietti E. The combined therapy with myo-inositol and D-chiro-inositol reduces the risk of metabolic disease in PCOS overweight patients compared to myo-inositol supplementation alone. (2012)
  14. James A Greenberg and Stacey J Bell. Multivitamin Supplementation During Pregnancy: Emphasis on Folic Acid and l-Methylfolate. (2011) 

Supplements commonly used for Polycistic Ovary Syndrome:


What is Inositol

Inositol is a nutritional supplement that people take for a range of medical conditions. It is considered a vitamin-like substance and was in the past characterized as one of the... read more…

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