Our view, stated clearly.
We choose 40:1 because it preserves myo-inositol as the dominant form, gives DCI a defined complementary role, and aligns with the strongest signal in a direct ratio-comparison study. Disclosing 1,000 mg MI and 25 mg DCI makes that research-informed choice fully transparent.
What does 40:1 actually mean?
For every 40 parts of myo-inositol, the formula contains one part D-chiro-inositol. In Optimal Ovarian Health, 1,000 mg MI divided by 25 mg DCI equals 40. Both numbers show the total exposure behind the ratio.1
This makes disclosed milligrams essential for product comparison: two formulas can both use 40:1 while providing very different daily amounts.
Where did the ratio come from?
The rationale is often linked to an approximately 40:1 MI/DCI relationship reported in plasma and to the tissue-specific roles of the two isomers. A 2019 clinical study directly compared seven ratios in 56 women with PCOS and reported the strongest results in its 40:1 group.2
That direct comparison provides a useful formulation signal for keeping MI dominant. Its findings apply to the studied population, amounts, duration, and outcomes; each ratio group included eight participants.
What do international guidelines say?
The 2023 International Evidence-based PCOS Guideline allows inositol to be considered according to individual preferences and notes possible improvement in selected metabolic measures. It does not designate one type, dose, or combination for universal use.5
ESTHELIV applies transparent formulation judgment within that boundary: 40:1 is our research-informed choice, and both milligram amounts are disclosed so consumers can evaluate the ratio and total serving together.
40:1 earns its place through an MI-led biological rationale, a favorable signal in direct human ratio research, and fully disclosed amounts of 1,000 mg MI and 25 mg DCI. It gives each form a clear assignment within the formula.
What a responsible formula should disclose
Exact form
“Inositol,” myo-inositol, and D-chiro-inositol are not equally precise label descriptions.
Daily amount
Read the full serving—not a single capsule—and do not confuse a ratio with a dose.
Formula purpose
Each form should have a defined role rather than being added for a front-label claim.
Evidence boundary
PCOS, fertility, and metabolic conditions require individualized medical care.
The 40:1 Ratio FAQs
Is 40:1 proven to be the best ratio?+
A direct comparison favored 40:1, and its MI-led structure gives ESTHELIV a coherent research-informed formulation choice. The result applies to the population and outcomes studied.
Does every 40:1 product deliver the same amount?+
No. Ratio describes proportion. Always check the milligrams of both MI and DCI per full daily serving.
Why not 20:1 or DCI alone?+
Those approaches change the relative exposure to each isomer. We prefer to keep myo-inositol dominant and give DCI a complementary role.
What is the ESTHELIV ratio and amount?+
The daily serving provides 1,000 mg myo-inositol and 25 mg D-chiro-inositol, which calculates to 40:1, plus 10 mg PureQQ® PQQ.
References
- 2023 International Evidence-based Guideline for PCOSTeede HJ, et al. Human Reproduction. 2023;38(9):1655–1679.
- Inositol for PCOS: systematic review informing the 2023 guidelineFitz V, et al. Journal of Clinical Endocrinology & Metabolism. 2024;109(6):1630–1655.
- Comparison of myo-inositol and D-chiro-inositol on ovarian and metabolic factorsPizzo A, et al. Gynecological Endocrinology. 2014;30(3):205–208.
- Comparison of seven MI/DCI ratiosNordio M, et al. European Review for Medical and Pharmacological Sciences. 2019;23(12):5512–5521.