D-chiro-inositol, supplement popular with women with PCOS, has a lesser known cousin, myoinositol, that is beginning to gain some attention in PCOS world. An Italian research laboratory has started to report findings from studies suggesting that with regard to fertility, at least, myoinositol may be the inositol of choice.
Eighty-four women at the AGUNCO Obstetrics and Gynecology Centre in Rome, Italy, were treated either with two grams of myoinositol twice a day, or 0.6 grams d-chiro-inositol twice a day. Eggs from both groups of subjects were then retrieved for use in intracytoplasmic sperm injection (ICSI) as part of in-vitro fertilization (IVF). The inositol supplement is a proprietary blend of myoinositol and folate, INOFOLIC, that currently is not available in the United States.
Researchers were able to harvest an equal number of eggs from each group. However, in the myoinositol-supplemented women, the quality of the eggs was better (more mature). This group also had more successful IVF outcomes than the d-chiroinositol-supplemented women.
Because there is such a preference for using d-chiro-inositol in the audience reading this blog, I contacted the researchers conducting these studies for clarification. It turns out, they recently had a letter just accepted for publication in Fertility and Sterility in which they discuss why they believe myoinositol works in a way that d-chiro-inositol does not.
In this letter, the researchers discuss that both myoinositol and d-chiro-inositol are involved in insulin function. In fact, a normal metabolic process is the conversion of into d-chiro-inositol. In most tissues, supplementing with d-chiro-inositol helps to maintain levels of this compound; this is why insulin resistance improves when supplementing with this particular compound.
However, ovaries do not develop insulin resistance. In a nutshell, that means that supplementing with d-chiro-inositol does not help them. The only way they can maintain healthy d-chiro-inositol levels, is to improve conversion of myoinositol to d-chiro-inositol. Eventually, that enhanced conversion process depletes myoinositol levels…and there is not enough d-chiro-inositol available to maintain normal ovarian function. Ironically, the only way to achieve healthy d-chiro-inositol levels in ovaries…seems to be to supplement with myoinositol. D-chiro-inositol supplementation does not appear to have the same effect.
A special thanks to Drs. Gianfranco Carmagno, PhD, and Vittorio Unfer, MD, and their Florida colleague Scott Roseff, MD, for dedicating so much time to pursuing this issue, and for taking the time to help me put this blog post together.
Unfer V, Carlomagno G, Rizzon P, Raffone E, Roseff S. Myo-inositol rather than D-chiro-inositol is able to improve oocyte quality in intracytoplasmic sperm injection cycles. A prospective, controlled, randomized trial. Eur Rev Med Pharmacol Sci 2011 Apr;15(4):452-7.
Papaleo E, Unfer V, Baillargeon JP, Fusi F, Occhi F, and DeSantis L. Myo-inositol rather than D-chiroinositol is able to improve oocyte quality in intracytoplasmic sperm injection cycles. A prospective, controlled, randomized trial. Fertil Steril 91:5; 1750-1754.