Uncovering the Secrets of D-chiro- inositol for PCOS - PCOS Diva
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Uncovering the Secrets of D-chiro- inositol for PCOS

Updated July 2019

by Amy Medling, Founder of PCOS Diva

I have written about demystifying Myo-inositol, a natural supplement used to help manage PCOS symptoms. Now it is time to uncover the secrets of D-chiro-inositol (DCI).  If you have yet to hear of myo-inositol (MYO), you’ll want to read my past posts and certainly read about the recent positive PCOS inositol research being done by Dr.  Antonio Simone Lagana.

Dr. Lagana shines a light on DCI. His studies conclude that, “In our experience, both inositol isoforms are effective in improving ovarian function and metabolism of patients with PCOS, although myo-inositol shows the most marked effect on the metabolic profile, whereas DCI reduces more hyperandrogenism.” (1) But that is only part of the story.

What are inositols?

Inositols are naturally occurring substances that can be found in many plants and animals. Commonly referred to as B8, they are not in fact vitamins, but sugars with a purpose. They are found in beans, fruits, grains, and nuts. Our bodies produce inositol by converting the food we eat. The most common inositols are Myo-insoitol (MYO) and D-Chiro inositol (DCI).

Inositols are not drugs, but rather nutritional supplements. In the case of D-chiro insoitol, it plays a part of healthy metabolism, and the body makes it from D-pinitol (another form of inositol) and myo-inositol. D-pinitol’s only role in the body is to be converted to myo-inositol and then to D-Chiro inositol. The human body can, in principle, make DCI from either D-pinitol or myo-inositol, but in practice, some people do not make enough DCI.

Why is D-Chiro Inositol Important?

D-chiro insoitol is used during insulin signal transduction, the body’s response to insulin. If DCI is deficient, insulin resistance can develop. The thought is that women with PCOS may not be able to convert MYO efficiently to DCI. Low levels of DCI have been observed in women with impaired insulin sensitivity and PCOS. (2) In fact, new research (8) indicates that the MYO to DCI conversion rate is impaired in women with PCOS due to insulin resistance which is commonly present. This inability to make the critical conversion is more likely to occur if the patient has first-degree diabetic relatives. This deficiency leads to too much testosterone and the symptoms of PCOS.

The image below depicts how myo-inositol is converted to DCI.Myo-vs-DCI-brief

The primary function of DCI is not to provide energy. Its primary function is as part of an important small molecule used during insulin signal transduction, a chemical signal chain that tells our bodies how to dispose of sugar. These small molecules are often called, “secondary messengers”.

 Myo-inositol and DCI are indeed different molecules. They belong to two different signal cascades and regulate different biological processes. It is a biochemical twist of fate that a deficiency of DCI, itself a carbohydrate, can make it so hard to correctly metabolize sugars, our energy carbohydrates. DCI is not abundant in our diets, so our bodies have to make DCI. And if our PCOS bodies are not efficient at converting myo-inositol and D-pinitol, the chemical signal chain breaks down and leads to high blood sugar, high insulin levels, and high androgen levels. These conditions can lead to type II diabetes, PCOS, endometriosis, and other disorders.

How Can D-Chiro Inositol Help PCOS?

1. DCI increases the action of insulin, and improves ovulatory function, decreases serum androgen, blood pressure and triglycerides (3)

Dr. John Nestler is a pioneer in studying DCI and women with PCOS. In his 1999 study (9), he looked at 44 overweight women with PCOS  who were given a daily dose of DCI for six to eight weeks. During the course of the study, those who took DCI displayed significant improvements in insulin sensitivity, blood pressure, and triglyceride levels, as well as a marked decrease in serum testosterone levels. Moreover, 19 of 22 subjects who received DCI ovulated during the study period, compared to only 6 of 22 in the placebo group. Dr. Nestler concluded,“D-Chiro-inositol increases the action of insulin in patients with the polycystic ovary syndrome, thereby improving ovulatory function and decreasing serum androgen concentrations, blood pressure, and plasma triglyceride concentrations.”

Since then, many studies have substantiated his initial findings and built upon his work. Now we know that small doses of D-chiro inositol can, in fact, help restore insulin sensitivity and improve the hormonal pattern in obese and hyperinsulinemic PCOS patients and even more if they have diabetic relations (8).

2. DCI decreases testosterone in women with PCOS (1, 4)

There is some indication that DCI can help lower testosterone. In a study involving lean women with PCOS, participants received 600 mg daily of DCI or a placebo for six to eight weeks. The DCI treated participants improved significantly, displaying a large decrease of 73% in testosterone levels versus no change in the placebo group. Women taking DCI also experienced reductions in insulin and triglyceride levels and blood pressure, whereas none of these changes were evident in the placebo group. (4) While DCI can help reduce testosterone, MYO is also effective.

3. DCI helps obese women with PCOS increase insulin sensitivity, in particular women who have diabetic relatives. (5)

A 2014 study (5) evaluated DCI supplementation on hormonal parameters and insulin sensitivity in a group of overweight/obese PCOS patients. After the treatment, researchers concluded that  DCI  is effective in restoring better insulin sensitivity and  balanced hormones (in particular LH/FSH) in obese insulin resistant  women with PCOS. They and subsequent researchers also found that PCOS patients with diabetic relatives showed greater improvement after DCI treatment.(8)

4. Combined therapy myo-inositol plus DCI is able to improve IVF outcomes.

Current research indicates that a combined therapy of myo-inositol plus DCI treatment may improve IVF outcomes. One study (6) looked at PCOS women undergoing IVF-ET.  They  were treated with myo-inositol combined with DCI or DCI alone. “The data clearly showed that only the combined therapy was able to improve oocyte and embryo quality, as well as pregnancy rates, in PCOS women undergoing IVF-ET.” Further research supports this finding, indicating that the combination of MYO and DCI improves pregnancy rates in women with PCOS undergoing IVF by reducing the risk of ovarian hyperstimulation syndrome (OHSS) (13).

5. Combined therapy myo-inositol plus DCI improves metabolic reduces the risk of metabolic disease in PCOS overweight patients compared to myo-inositol supplementation alone. (7)

In this 2012 study, 50 overweight women with PCOS were enrolled and divided in two groups to receive combined therapy. One group was treated with myo-inositol in combination with DCI and the other was treated with myo-inositol alone for a period of six months. The researchers concluded that, “the combined administration of myo-inositol and DCI should be considered as the first line approach in PCOS overweight patients, being able to reduce the metabolic and clinical alteration of PCOS and, therefore, reduce the risk of metabolic syndrome.” Since then, several larger studies have confirmed these findings (8).

Interestingly, combined treatment of inositol isomers such as myo-inositol (MI) and D-chiro inositol (DCI) should be applied at a specific ratio, which is known as the plasma physiologic ratio (MI/DCI: 40/1). Otherwise, immature oocytes can appear, and the effectiveness of inositol is decreased in the treatment of PCOS. (10)  Ovasitol offers this exact ratio, which may explain its effectiveness and popularity.  


Can I use D-Chiro Inositol While Pregnant or Breastfeeding?

The use of insoitol has never been evaluated in a clinical trial for its use or safety during pregnancy or while breastfeeding. However, DCI is a natural human metabolite; it is essential to metabolic processes all over your body; and there is no reason to believe that it may be harmful. If you decide to discontinue DCI, you should speak to your doctor about other ways to manage your insulin resistance. Women with PCOS are at a higher risk of developing gestational diabetes, and insulin resistance is an important factor in the outcome of the pregnancy. It is best to make the decision whether to use DCI while pregnant and  breastfeeding in conjunction with your physician who can help weigh the benefits and risks.

Where Can I Find D-Chiro Inositol?

D-chiro inositol isn’t as readily available as myo-inositol. DCI alone is available from Chiral Balance. Their (DCI) is sourced from Spain and is extracted from carob pods and then converted and purified to pharmaceutical grade DCI. DCI is quite a bit more expensive than myo-inositol because it isn’t readily available from dietary sources. Myo-inositol can be sourced from wheat, corn, or soy.

I encourage you to choose an inositol supplement which provides the proper balance of MYO and D-chiro inositols (40/1) since most of the current research indicates that while both are critical, the amount needed of each is very different and they are most effective when used together. (10, 11, 12)

I use a combination myo-inositol/d-chiro inositol product called Ovasitol.  For more info on Ovasitol  read this post.

Amy Medling, best-selling author of Healing PCOS and certified health coach, specializes in working with women with Polycystic Ovary Syndrome (PCOS), who are frustrated and have lost all hope when the only solution their doctors offer is to lose weight, take a pill, and live with their symptoms. In response, Amy founded PCOS Diva and developed a proven protocol of supplements, diet, and lifestyle programs that offer women tools to help gain control of their PCOS and regain their fertility, femininity, health, and happiness. 


(1)  Laganà AS, Borrielli I, Barbaro L, Pizzo A (2013) Myo-Inositol Vs D-Chiro- Inositol: preliminary data on the comparison between their effects on ovarian function and metabolic factors in women with PCOS. Proceedings of The World Congress on Building Consensus out of Controversies in Gynecology, Infertility and Perinatology (BCGIP-cogi) (Istanbul, Turkey, 30th May – 2nd June 2013).

(2) Low levels of DCI, and inositol phosphoglycans have been observed in individuals with impaired insulin sensitivity and PCOS (Susuki 1994, Jung 2005, Cheang 2008, Baillargeon 2010).

(3) Ovulatory and metabolic effects of D-chiro-inositol in polycystic ovary syndrome (1999) Department of Medicine, Medical College of Virginia, Virginia Commonwealth University, Richmond Virginia.

(4) Iuorno, Maria J., et al. “Effects Of D-Chiro-Inositol In Lean Women With The Polycystic Ovary Syndrome.” Endocrine Practice, vol. 8, no. 6, 2002, pp. 417–423., doi:10.4158/ep.8.6.417.

(5) Modulatory role of D-chiro-inositol (DCI) on LH and insulin secretion in obese PCOS patients. Genazzani AD1, Santagni S, Rattighieri E, Chierchia E, Despini G, Marini G, Prati A, Simoncini T. http://www.ncbi.nlm.nih.gov/pubmed/24601829

(6) Colazingari, Sandra, et al. “The Combined Therapy Myo-Inositol plus d-Chiro-Inositol, Rather than d-Chiro-Inositol, Is Able to Improve IVF Outcomes: Results from a Randomized Controlled Trial.” Archives of Gynecology and Obstetrics, vol. 288, no. 6, 2013, pp. 1405–1411., doi:10.1007/s00404-013-2855-3.

(7)  Eur Rev Med Pharmacol Sci. 2012 May;16(5):575-81. 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. Nordio M, Proietti .  http://www.ncbi.nlm.nih.gov/pubmed/22774396

(8) Unfer, Vittorio et al. “Myo-inositol effects in women with PCOS: a meta-analysis of randomized controlled trials.” Endocrine connections vol. 6,8 (2017): 647-658. doi:10.1530/EC-17-0243 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5655679/

(9) Nestler, John E., et al. “Ovulatory and Metabolic Effects of d-Chiro-Inositol in the Polycystic Ovary Syndrome.” New England Journal of Medicine, vol. 340, no. 17, 1999, pp. 1314–1320., doi:10.1056/nejm199904293401703.

(10) Günalan, Elif, et al. “The Effect of Nutrient Supplementation in Management of Polycystic Ovary Syndrome Associated Metabolic Dysfunctions: A Critical Review.” Journal of the Turkish-German Gynecological Association, 2018, doi:10.4274/jtgga.2018.0077.

(11) Sortino, Maria A et al. “Polycystic Ovary Syndrome: Insights into the Therapeutic Approach with Inositols.” Frontiers in pharmacology vol. 8 341. 8 Jun. 2017, doi:10.3389/fphar.2017.00341

(12) Gateva, Antoaneta, et al. “The Use of Inositol(s) Isomers in the Management of Polycystic Ovary Syndrome: a Comprehensive Review.” Gynecological Endocrinology, vol. 34, no. 7, 2018, pp. 545–550., doi:10.1080/09513590.2017.1421632.

(13) Mendoza, Nicolas, et al. “Comparison of the Effect of Two Combinations of Myo-Inositol and D-Chiro-Inositol in Women with Polycystic Ovary Syndrome Undergoing ICSI: a Randomized Controlled Trial.” Gynecological Endocrinology, vol. 35, no. 8, 2019, pp. 695–700., doi:10.1080/09513590.2019.1576620.

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  1. I’ve had a terrible experience so far with Myo Inositol. My naturopath recommended I start at half the dose and work up to full tsp daily. I couldn’t stomach it – crazy bloating, stomach pains. I cut back to 1/4tsp of the powder and it seems to have controlled the basic issues, but I find it makes my smoothies have a crystal texture to them. like flaked glass almost.

    Not sure how normal this is – I’ve only been on it about 6 weeks. Going back to see the naturopath in about a week and a half….maybe the capsules are easier to take?

  2. I’ve heard that caffeine kills inositol… do you know if this is true? I’ve been taking myo for a year with good results — all while drinking coffee everyday. I just decided (after reading this article) to start DCI. I wonder if my current results on myo, and my future results with DCI would be even better if I gave up coffee? Thanks for your input in advance!! 🙂

  3. I do not see a problem with coffee (in moderation) and Myo-inositol. There are no studies which specifically links coffee to NTDs. There is one study which found a possible link to caffeine intake, but the authors included ALL sources of caffeine, including tea, chocolate, coffee, etc. It looks like there was a single 1997 study, done in mice, which demonstrated that myo-inositol might reduce the risk of “folate-resistant” NTDs, but nothing was done on humans.

  4. Hi. Love the site. i was just wondering what worked better for you – taking Ovasitol, or the combination of Chiral Balance’s d-chiro-inositol and Ovaboost ?

  5. I am going to try inositol and d pinitol. should they be taken at different parts of the day?? And if I weigh 118, how much of each would be a good starting place, please??

  6. I have PCOS and I’m also post-menopausal (48 yrs old). I take Spironolactone.
    What benefit, if any, would I receive from taking this??

  7. Hello, I have PCOS and my main symptoms are lack of a period, insulin resistance, hair thinning and falling out, and acne. I was on BC pills but I was getting a yeast infection every month on them. I want to regulate my cycle naturally. I have changed my diet and am looking to get ovasitol. However, would this work for me if I’m not trying to get pregnant? I just want to have a regular period and diminish the pcos symptoms. Right now I’m taking Biotin, Magnesium, Vitamin B12 and Vitamin D. Any suggestions would be appreciated!

  8. I take myo inositol 1000mgs with DCI 600mgs a day (I’m childfree BTW so pregnancy I could care less about), is this optimal for weight loss in combination with stripped down keto diet?

  9. I have mild pcos, with irregular monthly cycles, a little bit insulin resistance, oily skin, thinning hair and had a horrible experience with myo inositol with cramps and crazy bloating and decided to try out Chiral balance d chiro inositol and for the very first time i saw ovulation signs and big ones with plenty cervical mucus and none of the horrible cramps that myo gave me. I wonder why is this …i take 600 mg daily. Can i take it with maca harmony from femmenessence??