Four medication classes do most of the prescription work in PCOS. Each targets a different aspect of the condition. Knowing what each does and doesn't do prevents the "I've tried three medications and nothing works" situation that often reflects poor alignment rather than treatment-resistant disease.
Metformin
Mechanism: improves cellular insulin sensitivity, reduces hepatic glucose output, modestly affects gut microbiome. Net effect in PCOS: reduces hyperinsulinemia, which reduces ovarian androgen production, which restores ovulation in many women.
Best for: insulin-resistant PCOS phenotype, particularly with metabolic features (elevated fasting insulin, glucose intolerance, weight gain). Helpful for cycle restoration and pregnancy planning. Standard dose: 500 mg titrated to 1500–2000 mg/day, often as extended-release for GI tolerance.
Common issues: GI side effects (diarrhea, bloating, metallic taste) in 25%+; usually mitigated by titration and ER formulation. B12 monitoring on long-term use. Not effective for adrenal PCOS phenotype.
Spironolactone
Mechanism: blocks androgen receptors and reduces androgen production. Originally a potassium-sparing diuretic; the androgen-blocking effect was a side effect that became the primary use in dermatology and PCOS.
Best for: androgen-driven symptoms — hormonal acne, hirsutism, androgenic alopecia — across PCOS phenotypes. Doesn't address insulin resistance or cycle regulation. Common dose: 50–200 mg/day. Acne effects appear at 8–12 weeks; hirsutism effects take 6+ months.
Common issues: requires contraception (teratogenic effects on male fetal development), potassium monitoring, occasional menstrual irregularity (paradoxical when used without OCP), breast tenderness. Cycle regulation is not a spironolactone effect — pair with combined hormonal contraception if cycle control is needed.
GLP-1 agonists
Mechanism: see GLP-1 articles for full coverage. In PCOS specifically: combination of weight loss, insulin sensitization, and direct ovarian androgen effects has growing evidence for insulin-resistant phenotype with metabolic comorbidities.
Best for: insulin-resistant PCOS with BMI ≥27 and significant metabolic features, particularly when metformin has been insufficient. Growing off-label use; some clinicians using it first-line for severely insulin-resistant cases. Standard dosing per GLP-1 protocols.
Common issues: GI side effects, cost (often not covered for PCOS indication specifically), fertility planning considerations (must stop before attempting pregnancy), muscle mass loss with weight loss.
Combined hormonal contraception (OCP)
Mechanism: suppresses HPO axis, prevents ovulation, provides predictable bleed via withdrawal, raises sex hormone-binding globulin (SHBG) which reduces free androgens.
Best for: cycle regulation, endometrial protection during anovulatory phases, androgen symptom reduction when pregnancy not planned, contraception. Common formulations: drospirenone-containing pills (Yaz, Yasmin) for additional anti-androgen effect.
Common issues: doesn't address underlying driver (when stopped, PCOS reappears), may worsen insulin resistance, contraindicated with certain comorbidities (smoker over 35, history of VTE, certain migraine patterns), post-pill recovery period after discontinuation.
How to combine them
Common combinations: metformin + spironolactone + OCP (cycle control, androgen blockade, insulin sensitization — covers the insulin-resistant phenotype thoroughly); GLP-1 + spironolactone (weight loss, androgen blockade — for women trying to lose weight before pregnancy attempts); metformin alone (during pregnancy attempts in insulin-resistant PCOS — restoring ovulation without contraception).
Informational only — medication decisions require evaluation by a clinician familiar with PCOS phenotype management.