Myo-inositol for fertility

On this page

1. What is myo-inositol?
2. Function and how it works
3. Fertility benefits
4. Recommended daily dose
5. Food sources
6. Cautions and contraindications
7. My Fertility Guide
8. Related pages

1. What is myo-inositol?

Myo-inositol is a sugar alcohol once classified as vitamin B8, abundantly present in the body where it acts as a secondary messenger inside cells, particularly in response to insulin and FSH signalling. It is the most abundant of the nine inositol stereoisomers and plays a key role in glucose metabolism, ovarian function and the central nervous system. Myo-inositol is one of the most evidence-based supplements for women with PCOS.

Reference ranges and recommended intakes vary from country to country — always interpret guidance against the recommendations of your own healthcare authority.

2. Function and how it works

Myo-inositol supports fertility through:

1. Insulin sensitivity. Myo-inositol acts as a secondary messenger for insulin; supplementation improves insulin sensitivity in PCOS.
2. FSH signalling. Myo-inositol relays the FSH signal in the ovary, supporting follicle maturation and ovulation.
3. Egg quality. Higher follicular fluid myo-inositol levels correlate with better egg quality.
4. Hormone balance. Myo-inositol reduces androgen levels in PCOS women, helping with acne, hirsutism and hair loss.
5. Cycle regularity. Many women with PCOS regain regular ovulation within 3–6 months of myo-inositol supplementation.

3. Fertility benefits

Myo-inositol is particularly useful for:

1. Women with PCOS
2. Women with insulin resistance or metabolic syndrome
3. Women with anovulation or irregular cycles
4. Couples preparing for IVF (improves egg quality and reduces stimulation drug requirements)
5. Women with poor egg quality or advanced reproductive age

Many practitioners use a combined formula of 40 parts myo-inositol to 1 part D-chiro-inositol, which mirrors the natural physiological ratio.

4. Recommended daily dose

I recommend a daily dose of 4 g of myo-inositol, taken in two doses of 2 g per day. Most clinical research uses this dose. For PCOS, take consistently for at least three months before assessing benefit. Combining with folic acid (200–400 µg) is the standard formulation in research.

5. Food sources

Myo-inositol is found in:

1. Citrus fruits (especially cantaloupe and oranges)
2. Beans and pulses
3. Whole grains
4. Nuts (almonds and walnuts)
5. Brewer's yeast

Food sources provide modest amounts; therapeutic doses for PCOS require supplementation.

6. Cautions and contraindications

1. Myo-inositol is well tolerated; mild gastrointestinal upset can occur at doses above 12 g per day.
2. People with bipolar disorder should consult their doctor before use, as inositol can affect mood signalling.
3. Discuss with your doctor if you take diabetes medication, as myo-inositol may enhance insulin effects.
4. Discontinue once pregnancy is confirmed unless advised otherwise by your doctor.
5. Always consult with a fertility specialist or your doctor before starting any new supplement regime.

7. My Fertility Guide

8. Related pages

• Fertility supplements directory
• Folic acid
• Chromium
• Alpha lipoic acid
• PCOS
• Insulin