Inositol: promising treatment for diabetes, PCOS, acne, and more

Inositol: promising treatment for diabetes, PCOS and acne

Inositol was once considered a B-vitamin (b8) but, since the discovery that our bodies manufacture enough of it, it is no longer considered a vitamin. Nevertheless, it’s closely related to the other B-vitamins. There are 9 forms of inositol; at least 2 of them (d-chiro-inositol and myo-inositol) have been shown to reduce insulin resistance. Myo-inositol is the most common form found in foods. The average human eats around 1 gram of inositol per day and manufactures 4 grams inside the body.1

There is no doubt that inositol can reduce insulin resistance. However, the studies were mostly carried out in women with PCOS, a disease that is characterized by irregular or absent menses and inability to become pregnant. PCOS women are frequently insulin resistant, just like type 2 diabetics and prediabetics, so there is a connection between the conditions.

Therefore, inositol is probably effective for diabetes, too.

The studies in women with PCOS have found that myo-inositol or d-chiro-inositol can:

  • Reduce insulin resistance2-8
  • Reduce fasting blood sugar and increase carbohydrate tolerance2-8
  • Reduce the ‘bad’ LDL cholesterol2, 9
  • Increase the ‘good’ HDL cholesterol2, 9
  • Reduce high blood pressure5, 7, 8
  • Reduce body weight3, 9

There are basically two commercially available forms of inositol: d-chiro-inositol or myo-inositol. Both forms are effective. The most common is myo-inositol, which is usually just referred to as inositol. If you find a supplement that says “inositol”, it’s probably the myo form.

I suggest buying myo-inositol since it’s cheaper and easier to find.

Studies found that doses of myo-inositol up to 18 grams per day for 3 months, or 2 grams per day for one year, were safe and well-tolerated. Side effects are usually mild and mostly include nausea, flatus and diarrhea.1

A note to coffee/caffeine consumers: Consuming coffee at the same time as inositol powder interferes with its absorption. Therefore, it’s best to avoid consuming coffee and caffeine at the same time as inositol powder.

Another interesting thing is that inositol in gelatin capsules is better absorbed than powder.10 On the other hand, the powder is much cheaper.

Dose: 1000-4000 milligrams of myo-inositol per day seems appropriate based on the research.



  1. Croze ML, Soulage CO. Potential role and therapeutic interests of myo-inositol in metabolic diseases. Biochimie. Jun 10.
  2. Minozzi M, Nordio M, Pajalich R. The Combined therapy myo-inositol plus D-Chiro-inositol, in a physiological ratio, reduces the cardiovascular risk by improving the lipid profile in PCOS patients. Eur Rev Med Pharmacol Sci. Feb;17(4):537-540.
  3. Genazzani AD, Prati A, Santagni S, et al. Differential insulin response to myo-inositol administration in obese polycystic ovary syndrome patients. Gynecol Endocrinol. Dec;28(12):969-973.
  4. Zacche MM, Caputo L, Filippis S, Zacche G, Dindelli M, Ferrari A. Efficacy of myo-inositol in the treatment of cutaneous disorders in young women with polycystic ovary syndrome. Gynecol Endocrinol. Aug 2009;25(8):508-513.
  5. 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. Mar-Apr 2009;13(2):105-110.
  6. 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. Mar 2008;24(3):139-144.
  7. Iuorno MJ, Jakubowicz DJ, Baillargeon JP, et al. Effects of d-chiro-inositol in lean women with the polycystic ovary syndrome. Endocr Pract. Nov-Dec 2002;8(6):417-423.
  8. Nestler JE, Jakubowicz DJ, Reamer P, Gunn RD, Allan G. Ovulatory and metabolic effects of D-chiro-inositol in the polycystic ovary syndrome. N Engl J Med. Apr 29 1999;340(17):1314-1320.
  9. 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. Nov-Dec 2003;7(6):151-159.
  10. De Grazia S, Carlomagno G, Unfer V, Cavalli P. Myo-inositol soft gel capsules may prevent the risk of coffee-induced neural tube defects. Expert Opin Drug Deliv. Sep;9(9):1033-1039.