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Myoinositol is the most abundant hexahydroxycyclohexane and is commonly found in a variety of foods.  It can even be manufactured by the body from glucose.

Several small studies have indicated that myoinositol supplementation results in significant improvement in several symptoms of polycystic ovarian syndrome: ovulation, weight loss, cholesterol and triglyceride levels and blood pressure.

Studies have found that myoinositol supplementation can:

  • Improve ovulation rates in women with PCOS
  • Decrease hirsutism in women with PCOS
  • Decrease the amount of androgens (male hormones) in women with PCOS
  • Decrease hormonal acne associated with PCOS
  • Reduce the hormone leptin which results in feelings of hunger
  • Improve insulin resistance through it’s involvement in insulin action
  • Relieve symptoms of depression
  • Help the metabolism of fats in the liver 

More Information:

Genazzani AD et al, Myo-inositol administration positively affects hyperinsulinemia and hormonal parameters in overweight patients with polycystic ovary syndrome, Gynecol Endocrinol. 2008 Mar;24(3):139-44

Gerli S et al, Randomized, double blind placebo-controlled trial: effects of myo-inositol on ovarian function and metabolic factors in women with PCOS, Eur Rev Med Pharmacol Sci. 2007 Sep-Oct;11(5):347-54

Larner J et al, In Vivo Conversion of myoinositol to chiroinositol in rat tissues, J Biol Chem 1992 Aug; 267(24):16904-16910

Costantino D, Minozzi G, Minozzi E, Guaraldi C  Metabolic and hormonal effects of myo-inositol in women with polycystic ovary syndrome: a double-blind trial,  Eur Rev Med Pharmacol Sci 2009 Mar-Apr; 13(2):105-10


To investigate the effects of treatment with Myo-inositol (an insulin sensitizing drug), on circulating insulin, glucose tolerance, ovulation and serum androgens concentrations in women with the Polycystic Ovary Syndrome (PCOS). Forty-two women with PCOS were treated in a double-blind trial with Myo-inositol plus folic acid or folic acid alone as placebo. In the group treated with Myo-inositol the serum total testosterone decreased from 99.5 +/- 7 to 34.8 +/- 4.3 ng/dl (placebo group: from 116.8 +/- 15 to 109 +/- 7.5 ng/dl; P = 0.003), and serum free testosterone from 0.85 +/- 0.1 to 0.24 +/- 0.33 ng/dl (placebo group: from 0.89 +/- 0.12 to 0.85 +/- 0.13 ng/dl; P = 0.01). Plasma triglycerides decreased from 195 +/- 20 to 95 +/- 17 mg/dl (placebo group: from 166 +/- 21 to 148 +/- 19 mg/dl; P = 0.001). Systolic blood pressure decreased from 131 +/- 2 to 127 +/- 2 mmHg (placebo group: from 128 +/- 1 to 130 +/-1 mmHg; P = 0.002). Diastolic blood pressure decreased from 88 +/- 1 to 82 +/- 3 mmHg (placebo group: from 86 +/- 1 to 90 +/- 1 mmHg; P = 0.001). The area under the plasma insulin curve after oral administration of glucose decreased from 8.54 +/- 1.149 to 5.535 +/- 1.792 microU/ml/min (placebo group: from 8.903 +/- 1.276 to 9.1 +/- 1.162 microU/ml/min; P = 0.03). The index of composite whole body insulin sensitivity (ISI comp) increased from 2.80 +/- 0.35 to 5.05 +/- 0.59 mg(-2)/dl(-2) (placebo group: from 3.23 +/- 0.48 to 2.81 +/- 0.54 mg(-2)/dl(-2); P < 0.002). 16 out of 23 women of Myo-inositol group ovulated (4 out of 19 in placebo group). Treatment of PCOS patients with Myo-inositol provided a decreasing of circulating insulin and serum total testosterone as well as an improvement in metabolic factors.

Genazzani AD, Lanzoni C, Ricchieri F, Jasonni VM  Myo-inositol administration positively affects hyperinsulinemia and hormonal parameters in overweight patients with polycystic ovary syndrome  Gynecol Endocrinol 2008 Mar; 24(3):139-44.


Objective. To evaluate the effects the administration of myo-inositol (MYO) on hormonal parameters in a group of PCOS patients. Design. Controlled clinical study. Setting. PCOS patients in a clinical research environment. Patients. 20 overweight PCOS patients were enrolled after informed consent. Interventions. All patients underwent hormonal evaluations and an oral glucose tollerance test (OGTT) before and after 12 weeks of therapy (Group A (n = 10): myo-inositol 2 gr. plus folic acid 200 mug every day; Group B (n = 10): folic acid 200 mug every day). Ultrasound examinations and Ferriman-Gallwey score were also performed. Main outcome measures. Plasma LH, FSH, PRL, E2, 17OHP, A, T, glucose, insulin, C peptide concentrations, BMI, HOMA index and glucose-to-insulin ratio.
Results. After 12 weeks of MYO administration plasma LH, PRL, T, insulin levels and LH/FSH resulted significantly reduced. Insulin sensitivity, expressed as glucose-to-insulin ratio and HOMA index resulted significantly improved after 12 weeks of treatment. Menstrual cyclicity was restored in all amenorrheic and oligomenorrheic subjects. No changes occurred in the patients treated with folic acid.
Conclusions. Myo-inositol administration improves reproductive axis functioning in PCOS patients reducing the hyperinsulinemic state that affects LH secretion.

Gerli S, Mignosa M, Di Renzo GC  Effects of inositol on ovarian function and metabolic factors in women with PCOS: a randomized double blind placebo-controlled trial.   Eur Rev Med Pharmacol Sci 2003 Nov-Dec; 7(6):151-9


BACKGROUND: Women with oligomenorrhea and polycystic ovaries show a high incidence of ovulation failure perhaps linked to insulin resistance and related metabolic features. A small number of reports shows that inositol improves ovarian function. Futhermore, in these trials the quality of evidence supporting ovulation is suboptimal, and few studies have been placebo-controlled. The aim of this study was to use a double-blind, placebo-controlled approach with detailed assessment of ovarian activity (two blood samples per week) to assess the validity of this therapeutic approach in this group of women.
METHODS: Of the 283 patients randomized, 2 withdrew before treatment commenced, 147 received placebo, and 136 received inositol (100 mg, twice a day). The women which discontined the study prematurely were more numerous in the treatment group (n = 45) than the placebo group (n = 15; P < 0.05).
RESULTS: The ovulation frequency estimated by the ratio of luteal phase weeks to observation weeks was significantly (P < 0.01) higher in the treated group (23%) compared with the placebo (13%). The time in which the first ovulation occurred was significantly (P < 0.05) shorter [23.6 d; 95% confidence interval (CI), 17, 30; compared with 41.8 d; 95% CI, 28, 56]. The number of patients failing to ovulate during the placebo-treatment period was higher (P < 0.05) in the placebo group, and in most cases ovulations were characterized by normal progesterone concentrations in both groups. The effect of inositol on follicular maturation was rapid, because the circulating concentration of E2 increased only in the inositol group during the first week of treatment. Significant (P < 0.01) weight loss (and leptin reduction) was recorded in the inositol group, whereas in the placebo group was recorded an increase of the weight (P < 0.05). A significant increase in circulating high-density lipoprotein was observed only in the inositol-treated group. Metabolic risk factor benefits of inositol treatment were not observed in the morbidly obese subgroup of patients (body mass index > 37). No change in fasting glucose concentrations, fasting insulin, or insulin responses to glucose challenge test was recorded after 14-wk of inositol and placebo therapy. There was an inverse relationship between body mass of the patients and the efficacy of the treatment.
CONCLUSIONS: These data support a beneficial effect of inositol in improving ovarian function in women with oligomenorrhea and polycystic ovaries.

Minozzi M, D’Andrea G, Unfer V Treatment of hirsutism with myo-inositol: a prospective clinical study Reprod Biomed Online. 2008 Oct;17(4):579-82.

The aim of this study was to evaluate the effects of myo-inositol treatment in hirsute women; changes in lipid pattern and insulin sensitivity were also considered. Forty-six hirsute women were enrolled at the first Institute of Obstetrics and Gynecology and evaluated at baseline and after receiving myo-inositol therapy for 6 months. Body mass index (BMI), hirsutism, serum concentrations of total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, apolipoprotein B, lipoprotein(a), serum adrenal and ovarian androgens, fasting glucose and insulin concentrations were evaluated. No changes in BMI were observed. The hirsutism decreased after therapy (P < 0.001). Total androgens, FSH and LH concentrations decreased while oestradiol concentrations increased. There was a slight non-significant decrease in total cholesterol concentrations, an increase in HDL cholesterol concentrations and a decrease in LDL cholesterol concentrations. No significant changes were observed in serum triglyceride, apolipoprotein B and lipoprotein(a) concentrations. Insulin resistance (P < 0.01), analysed by homeostasis model assessment, was reduced significantly after therapy. Administration of oral myo-inositol significantly reduced hirsutism and hyperandrogenism and ameliorated the abnormal metabolic profile of women with hirsutism.

Pascal M.W. Groenen, Hans M.W.M. Merkus, Fred C.G.J. Sweep, Ron A. Wevers, Fokje S.M. Janssen and Régine P.M. Steegers-Theunissen Kinetics of myo-inositol loading in women of reproductive age Ann Clin Biochem 2003;40:79-85


Background: Myo-inositol plays a key role in an important intracellular signalling pathway. A deranged myo-inositol metabolism has been associated with neural tube defects. A myo-inositol loading test was performed to investigate the kinetics in healthy women of reproductive age.

Methods: Five healthy non-obese females {mean age (standard deviation: SD) 22·8 (2·2) years} were recruited at the University Medical Center Nijmegen. Blood samples were drawn fasting and at 20, 40, 60, 90, 180 and 270 min after ingestion of 100 mg/kg body weight of myo-inositol. Urine samples were collected before myo-inositol loading and at 180 and 270 min post-loading. Samples were analysed for serum myo-, epi- and scyllo-inositol and glucose concentrations by gas chromatography. Plasma insulin concentrations were determined by radio-immunoassay. Random intercept models were fitted to evaluate the data.

Results: The estimated myo-inositol and scyllo-inositol concentrations both reached maximum values at 180 min post-loading, respectively: mean (SD) 101·5 (9·2) µmol/L and 1·09 (0·11) µmol/L. The estimated plasma insulin and serum glucose concentrations decreased slightly but significantly during the experiment: P < 0·0001 and P < 0·05, respectively. At 180 and 270 min post-loading, urinary myo-inositol concentrations were increased and urinary glucose concentrations were unchanged.

Conclusions: Myo-inositol enters the bloodstream quickly after oral ingestion and a small amount of myo-inositol is converted to scyllo-inositol. The synthesis of glucose from myo-inositol could not be detected by serum measurements. These data can be used in further research into the association between myo-inositol and neural tube defects.

Papaleo E et al Myo-inositol may improve oocyte quality in intracytoplasmic sperm injection cycles. A prospective, controlled, randomized trial, Fertil Steril. 2009 May;91(5):1750-4. Epub 2008 May 7


OBJECTIVE: To determine the effects of myo-inositol on oocyte quality in polycystic ovary syndrome (PCOS) patients undergoing intracytoplasmic sperm injection (ICSI) cycles. DESIGN: A prospective, controlled, randomized trial. SETTING: Assisted reproduction centers. PATIENT(S): Sixty infertile PCO patients undergoing ovulation induction for ICSI. INTERVENTION(S): All participants underwent standard long protocol. Starting on the day of GnRH administration, 30 participants received myo-inositol combined with folic acid (Inofolic) 2 g twice a day and 30 control women received folic acid alone, administrated continuously. MAIN OUTCOME MEASURE(S): Primary end points were number of morphologically mature oocytes retrieved, embryo quality, and pregnancy and implantation rates. Secondary end points were total number of days of FSH stimulation, total dose of gonadotropin administered, E(2) level on the day of hCG administration, fertilization rate per number of retrieved oocytes, embryo cleavage rate, live birth and miscarriage rates, cancellation rate, and incidence of moderate or severe ovarian hyperstimulation syndrome. RESULT(S): Total r-FSH units (1,958 +/- 695 vs. 2,383 +/- 578) and number of days of stimulation (11.4 +/- 0.9 vs. 12.4 +/- 1.4) were significantly reduced in the myo-inositol group. Furthermore, peak E(2) levels (2,232 +/- 510 vs. 2,713 +/- 595 pg/mL) at hCG administration were significantly lower in patients receiving myo-inositol. The mean number of oocytes retrieved did not differ in the two groups, whereas in the group cotreated with myo-inositol the mean number of germinal vesicles and degenerated oocytes was significantly reduced (1.0 +/- 0.9 vs. 1.6 +/- 1.0), with a trend for increased percentage of oocytes in metaphase II (0.82 +/- 0.11% vs. 0.75 +/- 0.15%). CONCLUSION(S): These data show that in patients with PCOS, treatment with myo-inositol and folic acid, but not folic acid alone, reduces germinal vesicles and degenerated oocytes at ovum pick-up without compromising total number of retrieved oocytes. This approach, reducing E(2) levels at hGC administration, could be adopted to decrease the risk of hyperstimulation in such patients.

Zacchè MM, Caputo L, Filippis S, Zacchè G, Dindelli M, Ferrari A Efficacy of myo-inositol in the treatment of cutaneous disorders in young women with polycystic ovary syndrome   Gynecol Endocrinol 2009 Aug; 25(8):508-13


BACKGROUND: Polycystic ovary syndrome (PCOS) is the most common endocrine cause of hirsutism, acne and pattern alopecia, often characterised by ovulation disorders (usually manifested as oligo- or amenorrhea). In addition, 30-40% of women with PCOS have impaired glucose tolerance, and a defect in the insulin signalling pathway seems to be implicated in the pathogenesis of insulin resistance. For this reason, insulin-lowering medications represent novel approach in women with PCOS. The aim of this study was to evaluate the effects of myo-inositol (MYO), an isoform of inositol, belonging to the vitamin B complex, in the treatment of cutaneous disorders like hirsutism and acne.
METHODS: Fifty patients with PCOS were enrolled in the study. BMI, LH, FSH, insulin, HOMA index, androstenedione, testosterone, free testosterone, hirsutism and acne were evaluated at the baseline and after receiving MYO therapy for 6 months.
RESULTS: After 3 months of MYO administration, plasma LH, testosterone, free testosterone, insulin and HOMA index resulted significantly reduced; no significant changes were observed in plasma FSH and androstenedione levels. Both hirsutism and acne decreased after 6 months of therapy.
DISCUSSION: MYO administration is a simple and safe treatment that ameliorates the metabolic profile of patients with PCOS, reducing hirsutism and acne.

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6 comments to Myoinositol

  • Kat

    Can myo-inositol be taken with DCI?

  • My PCOS Info

    Yes, you certainly can take both myoinositol (MYO) and d-chiro inositol (DCI) together. In fact, some studies have found a greater benefit to taking myoinositol & d-chiro inositol together than either one by itself. MYO seems to improve fertility aspects of PCOS including egg quality more than DCI, whereas DCI seems to improve general biochemical markers and insulin sensitivity more than MYO, things like cholesterol, triglycerides, blood sugar levels and HbA1c, and inflammatory markers like C-reactive protein which tend to be elevated in women with PCOS.

  • Donika

    Can i take myo forever i have to pcos :s

  • My PCOS Info

    Hi Donika,

    I’m not aware of any long-term safety studies on myo-inositol or d-chiro inositol for that matter, and it is unlikely that any will be done as they are both naturally occurring substances found in food and manufactured in healthy human bodies. Therefore a definitive answer is not possible.

    I have been taking DCI for about 5 years now and intend to take it ‘forever’ or until such time as it is possible to repair the genetic defects which appear to be behind PCOS. I personally don’t see much of a result from taking myo-inositol, but the only thing that would concern me about taking MI longer-term is that the dose required to treat PCOS is quite high, though not as high as the doses used to treat some psychiatric disorders.

    On balance, there is probably much greater benefit from managing the biochemical abnormalities which occur in PCOS than any potential harm from taking a high dose of myo-inositol for a long period of time.

    Good luck.

  • Amanda

    Can you please tell me the correct dosage for myo-inositol?

  • My PCOS Info

    The studies into using inositols for the treatment of PCOS have in general used 4000 mg or 4 g per day.

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