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D-chiro-inositol

Inositol stereoisomer, supplement. Usually used combined with myo-inositol in 40:1 ratio

ATC code: A11JA-D-CHIRO-INOSITOL

Brand names – supplements: Inofolic Combi, Ovasitol, Now D-Chiro-Inositol, Source Naturals D-Chiro-InositolSupplements are not tested in clinical trials and are not registered as medications.

Updated · Methodology

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

D

Polycystic ovary syndrome

Not recommended

D-chiro-inositol as monotherapy in PCOS has no quality evidence base. Most inositol PCOS RCTs used either myo-inositol monotherapy or myo:D-chiro 40:1 combination (Inofolic Combi, Ovasitol). The Pundir 2018 (BJOG) meta-analysis pooled inositols as a class and did not directly compare the 40:1 combination against myo-inositol monotherapy. 2023 PCOS guideline classifies inositols (without specifying form) as experimental therapy with possible effect. In PCOS the goal matters: combined oral contraceptives address cycle regulation and hyperandrogenism, while for ovulation induction when seeking pregnancy the first line is letrozole (ESHRE 2023), with metformin as an adjunct. If D-chiro-inositol monotherapy was recommended for PCOS, myo-inositol monotherapy or 40:1 combination under gynaecology supervision is preferable.

Sources

  1. European Review for Medical and Pharmacological Sciences: Inositols in polycystic ovary syndrome: 40:1 myo:D-chiro ratio rationale (2014)
  2. BJOG: Inositol treatment of anovulation in women with polycystic ovary syndrome: meta-analysis of randomised trials (2018)
  3. ESHRE: International evidence-based guideline for the assessment and management of polycystic ovary syndrome (2023)

ICD-10: E28.2 · ICD-11: 5A80.1

D

Type 2 diabetes mellitus

Not recommended

D-chiro-inositol is an inositol isomer sold as a supplement and promoted for blood sugar control and better insulin sensitivity. For type 2 diabetes the convincing benefit has not been shown: there is no evidence base for this use, and the available data are weak and do not confirm an effect on glucose or . What helps type 2 diabetes is changes to diet and weight, regular physical activity, and medicines with an established evidence base such as metformin. The compound itself is harmless in this role, but it should not replace prescribed treatment.

Sources

  1. BJOG: Inositol treatment of anovulation in women with polycystic ovary syndrome: meta-analysis of randomised trials (2018)

ICD-10: E11 · ICD-11: 5A11

F

Pregnancy planning and ovulation stimulation

Not recommended

Mono D-chiro-inositol is often bought to prepare for pregnancy or IVF, yet there is no solid evidence that it improves the outcomes people actually want, egg quality and ovulation. In head-to-head trials myo-inositol improved oocyte and embryo quality while D-chiro-inositol did not (Unfer, 2011), and only the myo plus D-chiro combination, not D-chiro alone, improved IVF outcomes (Colazingari, 2013). The evidence also runs the other way: raising the D-chiro-inositol dose (600 to 2400 mg) progressively worsened oocyte quality and ovarian response (Isabella, 2012), higher follicular-fluid D-chiro correlated with poorer blastocysts (Ravanos, 2017), and high doses produced polycystic-like ovarian changes in mice (Bevilacqua, 2021). For someone trying to conceive, high-dose mono D-chiro-inositol can push against the very goal it is taken for. If inositol is considered at all, the stronger evidence sits with myo-inositol or a physiological myo-to-D-chiro combination, and the choice is worth discussing with a clinician.

Sources

  1. ESHRE: International evidence-based guideline for the assessment and management of polycystic ovary syndrome (2023)
  2. International Journal of Molecular Sciences: High Doses of D-Chiro-Inositol Alone Induce a PCO-Like Syndrome and Other Alterations in Mouse Ovaries (2021)
  3. Fertility and Sterility: The D-chiro-inositol paradox in the ovary (2011)
  4. European Review for Medical and Pharmacological Sciences: Can high levels of D-chiro-inositol in follicular fluid exert detrimental effects on blastocyst quality? (2017)
  5. European Review for Medical and Pharmacological Sciences: Myo-inositol rather than D-chiro-inositol is able to improve oocyte quality in intracytoplasmic sperm injection cycles. A prospective, controlled, randomized trial (2011)
  6. Journal of Ovarian Research: CONCERN: Does ovary need D-chiro-inositol? (2012)
  7. Archives of Gynecology and Obstetrics: The combined therapy myo-inositol plus D-chiro-inositol, rather than D-chiro-inositol, is able to improve IVF outcomes: results from a randomized controlled trial (2013)

ICD-10: N97.0 · ICD-11: GA31.Z

How to read tiers A–F
  • AStrong evidence – first or second line in international guidelines
  • BRecommended in selected cases
  • CStudy data contradict each other
  • DBenefit not proven, no documented harm
  • FDocumented harm, or risk without benefit

Mechanism of action

D-chiro-inositol is derived from myo-inositol by epimerase. In the cell D-chiro-inositol participates in phosphoglycan mediator synthesis regulating pyruvate dehydrogenase activity and glucose storage as glycogen. In PCOS patients the myo:D-chiro ratio in ovaries is disrupted (increased in favour of D-chiro), reducing FSH sensitivity. Physiological myo:D-chiro ratio in healthy women plasma is 40:1; Facchinetti 2014 recommended reproducing this ratio in combined PCOS supplements. Oral bioavailability is high, peak in 2 hours, renal excretion.

Safety

Contraindications

  • Known hypersensitivity
  • Pregnancy – do not exceed 1 g/day

Serious adverse effects

  • Allergic reactions (rare)
  • Reduced oocyte quality at high doses (>1.2 g/day)

Common adverse effects

  • Nausea
  • Flatulence
  • Dizziness (rare)

Pregnancy: can you take D-chiro-inositol?

Limited RCT data in pregnancy. D-chiro-inositol at >1.2 g/day in animal studies reduced oocyte quality; do not exceed 1 g/day in PCOS patients during pregnancy planning.

Breastfeeding: can you take D-chiro-inositol?

Few data on milk transfer. Lactating women should avoid high-dose monoproduct.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

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Frequently asked

What is D-chiro-inositol used for?

D-chiro-inositol is evaluated for the following indications with varying evidence strength: Type 2 diabetes mellitus (evidence tier D), Polycystic ovary syndrome (evidence tier D), Pregnancy planning and ovulation stimulation (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of D-chiro-inositol?

Common side effects of D-chiro-inositol (≥ 1 in 100): Nausea, Flatulence, Dizziness (rare). See the Safety section for uncommon and serious reactions.

Is D-chiro-inositol safe during pregnancy?

Limited RCT data in pregnancy. D-chiro-inositol at >1.2 g/day in animal studies reduced oocyte quality; do not exceed 1 g/day in PCOS patients during pregnancy planning.

Is D-chiro-inositol compatible with breastfeeding?

Few data on milk transfer. Lactating women should avoid high-dose monoproduct.

Who should not take D-chiro-inositol?

D-chiro-inositol is contraindicated in: Known hypersensitivity; Pregnancy – do not exceed 1 g/day. Full list in the Safety section.

Other drugs in this group

D-ribose, Diindolylmethane (DIM), Epigallocatechin-3-gallate (EGCG, main green tea polyphenol), Elderberry (Sambucus nigra), Mixed tocopherols, Pumpkin seed oil (Cucurbita pepo, Cucurbita maxima), Spirulina, Ashwagandha (Withania somnifera)