The benefits of inositol for fertility

Inositol is a naturally occurring compound that belongs to the B-vitamin complex, found in fruits, grains and nuts. It comes in two main forms — myo-inositol and D-chiro-inositol — of which myo-inositol is the most studied and most commonly used for fertility support. Research suggests inositol may benefit both male and female fertility, and it is particularly relevant for women with PCOS (PMOS) and irregular cycles.

An important update: On 12 May 2026, an international consensus published in The Lancet renamed Polycystic Ovary Syndrome (PCOS) to Polyendocrine Metabolic Ovarian Syndrome (PMOS). The new name reflects the condition's wider hormonal and metabolic effects, including insulin resistance, which is central to why inositol is so relevant to PCOS management. Both names will be used during the transition to the 2028 ICD update. Read our explainer on what the rename means for your hormones and fertility.

Inositol and female fertility

Inositol has a growing body of research behind its role in supporting female fertility. Here are some of the key areas where it may be beneficial:

Egg quality

Myo-inositol may help to support the quality of eggs produced by the ovaries, which may improve the conditions for successful conception. Research suggests inositol may support the quality of the follicles in which eggs mature, particularly in women undergoing IVF or ovulation induction.¹

Menstrual cycle regularity

Inositol may help to support more regular menstrual cycles by improving hormonal balance. This may be particularly beneficial for women who experience irregular cycles or cycle irregularities associated with conditions such as PCOS (PMOS).

Ovulatory function

Myo-inositol may support ovulatory function by improving the sensitivity of the ovaries to FSH and LH, the hormones responsible for triggering ovulation. Studies have found that myo-inositol supplementation may increase ovulation rates in women with PCOS (PMOS) and those with insulin resistance.¹

Gestational diabetes risk

Research suggests inositol may help to reduce the risk of gestational diabetes by improving insulin sensitivity and supporting blood sugar regulation during pregnancy. Two separate trials found that myo-inositol supplementation reduced the incidence of gestational diabetes by 65 to 87% in high-risk pregnancies.²

Miscarriage risk reduction

Some research suggests inositol may support pregnancy outcomes in women who have previously experienced recurrent miscarriages, potentially through its role in improving egg quality and reducing the risk of chromosomal abnormalities, though more research is needed in this specific area.

Inositol and PCOS (PMOS)

PCOS (PMOS) affects approximately 1 in 10 women of reproductive age and is characterised by elevated androgens, insulin resistance and irregular menstrual cycles. It is one of the most common causes of fertility difficulties. Myo-inositol has become one of the most researched nutritional supplements for PCOS (PMOS), with studies suggesting it may support several of the condition's core features:

Insulin resistance

Insulin resistance is central to PCOS (PMOS) and is now reflected in the condition's new name. Myo-inositol acts as a second messenger in insulin signalling pathways and may help improve insulin sensitivity, supporting more stable blood sugar levels and potentially reducing the hormonal cascade that elevated insulin triggers in PCOS (PMOS).¹

Ovarian function

Research suggests myo-inositol may improve ovarian function in women with PCOS (PMOS), including increasing the number of mature follicles, supporting oocyte quality and increasing the chances of ovulation. Read our detailed review of the evidence for myo-inositol and PCOS here.

Hormonal balance

Myo-inositol may help reduce androgen levels in women with PCOS (PMOS), which may lead to improvements in symptoms such as acne, hirsutism and irregular cycles. Studies have found reductions in testosterone and LH levels with myo-inositol supplementation compared to placebo.¹

Inositol and male fertility

Inositol has also been studied in the context of male fertility. Research suggests it may support several aspects of sperm health:

• Sperm count: Myo-inositol may support sperm production by reducing oxidative stress and DNA damage in sperm cells.
• Sperm motility: Research suggests inositol may support sperm motility, the ability of sperm to swim effectively towards the egg, which is important for successful fertilisation.
• DNA integrity: Inositol may help reduce the risk of DNA damage in sperm, which may support sperm quality and conception outcomes.
• Metabolic health: By supporting insulin sensitivity, inositol may also benefit male fertility indirectly through its effects on metabolic health, which has a known relationship with sperm quality.

Myo-inositol vs D-chiro-inositol: which is better for fertility?

Myo-inositol is the form with the most robust fertility-specific evidence, particularly for ovarian function and PCOS (PMOS). D-chiro-inositol is found in lower concentrations in the ovaries and plays a different metabolic role. Some research has explored combined formulations, but myo-inositol alone or combined with folate remains the most widely studied and recommended approach for fertility support.

For a deeper look at the evidence, read our evidence review of myo-inositol and folate for PCOS here.

Further reading

• Myo-inositol and folate for PCOS (PMOS) — the clinical evidence in detail
• Choline and inositol for fertility — how these two nutrients support reproductive health through distinct mechanisms
• Folate, vitamin D and PCOS (PMOS) — why bioavailable folate matters alongside inositol
• NAC and PCOS (PMOS) — antioxidant support for oxidative stress and insulin sensitivity
• PCOS has been renamed PMOS — what the new name means for your hormones and fertility

FAQs: inositol and fertility

What does inositol do for fertility?

Myo-inositol may support female fertility by improving insulin sensitivity, supporting ovulatory function, improving hormonal balance and supporting egg quality. For men, it may support sperm count, motility and DNA integrity. It is particularly well researched for women with PCOS (PMOS).

How much inositol should I take for fertility?

The doses used in PCOS and fertility research typically range from 2g to 4g of myo-inositol per day, often combined with 200mcg of folate. Zita West Inositol and Folate provides a clinically aligned dose in powder format. Always consult your healthcare provider for guidance on the right dose for your situation.

How long does inositol take to work for fertility?

Most clinical studies on inositol for PCOS (PMOS) run for 12 to 24 weeks. Improvements in hormonal markers and ovulatory function are typically reported after 3 months of consistent supplementation, though individual responses vary.

Can I take inositol and folate together?

Yes. Combining myo-inositol with bioavailable folate is the most commonly studied approach and addresses both insulin signalling and methylation pathways relevant to fertility. Zita West Inositol and Folate combines both in a single powder formulation.

Is inositol safe to take when trying to conceive?

Myo-inositol is generally considered safe at the doses used in research. Always discuss any new supplement with your healthcare provider, particularly if you are undergoing fertility treatment or taking other medications.

What is the difference between PCOS and PMOS?

PMOS (Polyendocrine Metabolic Ovarian Syndrome) is the new name for PCOS, adopted following an international consensus published in The Lancet in May 2026. The condition is the same but the new name better reflects its wider hormonal and metabolic effects. Read our full explainer on the rename.

References

1. Genazzani AD et al. (2008). Myo-inositol administration positively affects hyperinsulinemia and hormonal parameters in overweight patients with polycystic ovary syndrome. Gynecological Endocrinology. PubMed
2. D'Anna R et al. (2013). Myo-inositol supplementation and onset of gestational diabetes mellitus in pregnant women with a family history of type 2 diabetes. Diabetes Care. PubMed

External references: NHS: Polycystic ovary syndrome (PCOS)  |  The Lancet: PMOS consensus 2026

This content is for educational purposes only and is not intended to diagnose, treat, or replace medical advice. Always consult your healthcare provider before starting any new supplement.