· By Amy Suzanne Upchurch, Founder + CEO of Pink Stork, Certified Health Coach, INHC
What is the best myo-inositol to D-chiro-inositol ratio?
Clinical research comparing different ratios of myo-inositol to D-chiro-inositol found that a 40:1 ratio was the most effective for restoring ovulation and normalizing key hormone markers, while formulas with too much D-chiro-inositol relative to myo-inositol actually performed worse.† Not for use during pregnancy. This is one of the more specific, checkable details worth knowing before choosing an inositol supplement, since ratio is not something every bottle discloses clearly.
What the research actually compared
A clinical trial evaluated seven different ratios of myo-inositol (MI) to D-chiro-inositol (DCI), ranging from DCI alone up to an 80:1 ratio, with ovulation as the primary outcome measured1. The trial found that the 40:1 ratio was the most effective for restoring ovulation and normalizing markers including FSH, LH, and free testosterone, and that increasing the proportion of D-chiro-inositol beyond that ratio actually reduced the beneficial effects at the reproductive level1. It's worth being precise about the study population: this particular trial was conducted in women being evaluated for polycystic ovary syndrome (PCOS), a population researchers have used to study inositol and ovulation because ovulatory irregularities are common and measurable in that group. A separate laboratory study using a mouse model found that a 40:1 ratio of myo-inositol to D-chiro-inositol was associated with favorable changes in the expression of genes involved in ovarian hormone signaling2.
This research is about the ratio and dose studied, not a claim that any Pink Stork product treats or diagnoses any medical condition. The National Institute of Child Health and Human Development notes that PCOS is diagnosed based on a specific combination of features and should be evaluated by a healthcare provider, not self-diagnosed based on supplement research alone3.
Why the ratio matters more than the total dose
A lot of inositol marketing focuses on total milligrams without disclosing the ratio between the two forms. Based on the research above, more D-chiro-inositol is not automatically better, and an imbalanced ratio may work against the outcome you're looking for. This is the exact kind of specific, checkable detail worth confirming before purchasing any inositol supplement.
What to check on an inositol supplement label
- Whether the product discloses a specific MI to DCI ratio, not just a combined total
- Whether the ratio matches what has been studied clinically, generally in the 40:1 range
- Third-party testing, since inositol supplements vary in purity and sourcing
"I would scream it from the mountaintops… gut health is so important, and specifically in fertility."
— Dr. Samantha Ess, ND, Naturopathic Doctor specializing in hormone health and fertility
What a clinically studied ratio looks like in a formula
Our 40:1 ratio of Myo-Inositol to D-Chiro-Inositol, Myo Chiro 40:1 delivers 2,000 mg Myo-Inositol to 50 mg D-Chiro-Inositol per serving, matching the ratio most consistently associated with favorable outcomes for ovarian health and cycle regularity in the research above.† Myo Chiro 40:1 supports healthy hormone signaling and ovarian health, and menstrual cycle regularity, and is not intended for use during pregnancy. If you are breastfeeding, talk with your healthcare provider before starting it.
"So many women just want to know they're doing this the right way, with something that's actually been studied, not just something that sounds good on Instagram," says Amy Suzanne Upchurch, Founder and CEO of Pink Stork.
If you're building a broader preconception routine, our guide on why your prenatal needs methylated folate covers what to look for once you transition from cycle support into pregnancy planning.
Frequently asked questions
What is the best ratio of myo-inositol to D-chiro-inositol?
Clinical research comparing seven different ratios found that 40:1 (myo-inositol to D-chiro-inositol) was most effective for restoring ovulation and normalizing hormone markers1.
Is more D-chiro-inositol always better?
No. The same research found that increasing D-chiro-inositol beyond the 40:1 ratio reduced the beneficial effects, rather than improving them1.
Was this research conducted in a general population or a specific one?
The primary clinical trial behind the 40:1 ratio was conducted in women being evaluated for PCOS. This is general research on inositol ratios and ovulation, not a claim that Myo Chiro 40:1 diagnoses or treats any medical condition1.
Can I take Myo Chiro 40:1 during pregnancy?
No. Myo Chiro 40:1 is not for use during pregnancy. Talk with your healthcare provider before use if you are breastfeeding.
What is the exact dose in Myo Chiro 40:1?
Each serving provides 2,000 mg of Myo-Inositol to 50 mg of D-Chiro-Inositol, matching the clinically studied 40:1 ratio.†
† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult your healthcare provider before starting any new supplement, especially during pregnancy, breastfeeding, or while managing a medical condition. Keep out of reach of children.
