Summary
Metformin Hydrochloride has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in PCOS (Polycystic Ovary Syndrome) would be drug repurposing rather than first-in-human development. This does not mean it is approved for PCOS (Polycystic Ovary Syndrome). ClinicalTrials.gov lists 8 registered trials linking Metformin Hydrochloride to PCOS (Polycystic Ovary Syndrome): 7 have completed; 1 is terminated, withdrawn, suspended or of unknown status. The most advanced is Phase 4 (NCT00471523). The largest enrolment is 119 participants (NCT02635386). Registration activity spans 2000 to 2025. The literature layer holds 5 publications for this pair: 5 clinical trial publications. Publication years run from 2013 to 2024. These are primary trial reports rather than syntheses, so results have not yet been pooled or graded independently.
The RepurpOS disease-intelligence file for Polycystic Ovary Syndrome ranks 177 candidate therapeutics from Open Targets, ChEMBL, DGIdb and PubMed; only a minority carry direct clinical evidence, and this page covers one of those. Spontaneous remission context recorded for the condition: PCOS is a lifelong endocrine disorder; complete spontaneous resolution rare; some phenotypic improvement with menopause; fertility returns in 50-70% with ovulation induction; metabolic features persist.
Evidence table
| Evidence tier | A · Strong |
|---|---|
| Evidence score | 58.5 (trials 28.5, literature 10.0, tier 15, approved bonus 5.0) |
| Registered trials | 8 total: 0 recruiting, 0 active / not yet recruiting, 7 completed, 1 other |
| Linked publications | 5 (5 clinical trial publications) |
| Agent type | Drug (Small molecule) |
| Development stage (any indication) | Approved |
| Mechanism / class | inhibitor |
| Data sources | DGIdb |
| Linked via biomarker / target | COXFA4L2 |
How the evidence score is calculated
- Each registered trial scores by status (recruiting / active / enrolling 3, completed 2.5, not yet recruiting 2, unknown 1, terminated / withdrawn / suspended 0.5) plus a phase bonus (phase 3-4 +2, phase 2 +1, phase 1 +0.5). The trial component is capped at 30.
- Each literature item scores by design (Cochrane review 5, meta-analysis 4, systematic review 3, RCT 3, clinical trial publication 2, curated reference 1.5, other PubMed record 1). The literature component is capped at 30.
- The existing evidence tier adds 15 (A / Strong), 10 (B / Moderate), 5 (C / Preliminary) or 0 (D / Anecdotal).
- Agents approved for any indication (max clinical phase 4) add 5, because an approved agent has an established safety profile that lowers the barrier to repurposing trials.
- The score ranks what has been studied, not what works. It does not read effect sizes or directions of effect.
Registered clinical trials
| NCT ID | Title | Status | Phase | Enrolment |
|---|---|---|---|---|
| NCT00471523 | Treatment of Anovulatory Infertility in PCOS Patients 2006 | completed | Phase 4 | 80 |
| NCT03086005 | Study to Assess the Effect of Metformin Supplementation on IVF Outcome in Patients With Polycystic Ovarian Syndrome. 2011 | completed | Phase 3 | 24 |
| NCT02635386 | EQW, DAPA, EQW/DAPA, DAPA/MET ER and PHEN/TPM ER in Obese Women With PolycysticOvary Syndrome (PCOS) 2016 | completed | Phase 3 | 119 |
| NCT01482286 | Effect of Weight and Insulin Sensitivity on Reproductive Function in PCOS 2012 | terminated | Phase 3 | 32 |
| NCT03259919 | Metformin Treatment of Pregnant Women With Polycystic Ovary Syndrome: a Pilot Study 2000 | completed | Phase 2 | 40 |
| NCT07399535 | Clinical Investigation of Herbal Formulation and Its Efficacy in Polycystic Ovarian Syndrome 2025 | completed | Phase 1 | 116 |
| NCT02689843 | Effects of Cyproterone Compound-spironolactone, Metformin and Pioglitazone on Inflammatory Markers in PCOS 2018 | completed | Early Phase 1 | 90 |
| NCT02341703 | Ovulation Induction in Clomiphene Citrate Resistant PCO Women 2015 | completed | Early Phase 1 | 100 |
Published literature
- Clinical trial publication Bioequivalence of Related GelShield(Ⓡ) Sustained-release Formulations of Metformin: A Pooled Pharmacokinetic AnalysisKrebs-Brown A, Brand KMG, Filho MAFN et al. · Clinical therapeutics · 2024 · PMID 38688745
- Clinical trial publication [Efficacy and mechanism of electroacupuncture on insulin resistant polycystic ovary syndrome]Yu LQ, Cao LY, Xie J et al. · Zhongguo zhen jiu = Chinese acupuncture & moxibustion · 2020 · PMID 32275366
- Clinical trial publication [Observation on therapeutic effect of polycystic ovary syndrome of damp-phlegm constitution treated with embedding therapy on back-shu points and front-mu points combined with needle-pricking therapy on Sifeng (EX-UE 10)]Chen R, Wang C, Yan QY · Zhongguo zhen jiu = Chinese acupuncture & moxibustion · 2014 · PMID 24946636
- Clinical trial publication Effect of metformin on the level of anti-Mullerian hormone in therapy of polycystic ovary syndrome in obese womenGrigoryan O, Absatarova J, Andreeva E et al. · Minerva ginecologica · 2014 · PMID 24569407
- Clinical trial publication Effect of metformin hydrochloride in correcting hyperinsulinemia and high leptin levels in treatment of infertile polycystic patientsIrfan A, Mughal IA, Jalali S · Journal of Ayub Medical College, Abbottabad : JAMC · 2013 · PMID 25098041
Mechanism and notes
Recorded mechanism or class: inhibitor.
OSMF's existing evidence tier for this pair is A (Strong), derived from the strength of the disease association recorded in DGIdb, in this case via the biomarker or target COXFA4L2. The tier describes how well the drug-disease link is documented, not how well the drug works.
Frequently asked questions
Is Metformin Hydrochloride approved for PCOS (Polycystic Ovary Syndrome)?
Metformin Hydrochloride has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in PCOS (Polycystic Ovary Syndrome) would be drug repurposing rather than first-in-human development. This does not mean it is approved for PCOS (Polycystic Ovary Syndrome). Approval status for the specific indication should always be confirmed with the relevant regulator and prescribing information.
Is Metformin Hydrochloride in clinical trials for PCOS (Polycystic Ovary Syndrome)?
ClinicalTrials.gov lists 8 registered trials linking Metformin Hydrochloride to PCOS (Polycystic Ovary Syndrome): 7 have completed; 1 is terminated, withdrawn, suspended or of unknown status. The most advanced is Phase 4 (NCT00471523). The largest enrolment is 119 participants (NCT02635386). Registration activity spans 2000 to 2025.
What does the evidence show for Metformin Hydrochloride in PCOS (Polycystic Ovary Syndrome)?
Metformin Hydrochloride has 7 completed trials and 5 linked publications for PCOS (Polycystic Ovary Syndrome). Completed trials may or may not have posted results; follow the NCT links to check. OSMF's existing evidence tier for this pair is A (Strong), derived from the strength of the disease association recorded in DGIdb, in this case via the biomarker or target COXFA4L2. The tier describes how well the drug-disease link is documented, not how well the drug works.
Cite this page
Data: ClinicalTrials.gov, PubMed, Open Targets, ChEMBL, DGIdb and the OSMF therapeutic agent database. Last updated 2026-07-05. Page built 2026-10-07.