Obesity, Anovulation & Hyperandrogenism in PCOS
Excess weight drives insulin resistance and androgen excess in PCOS.
- ~10%: Women with PCOS (of reproductive age)
- ~60–80%: Obesity overlap (of PCOS patients)
- 0–4/yr: Ovulatory cycles (typical anovulation)
- ↑1.5–2×: Free testosterone (vs normal range)
Why weight and ovulation are linked
Adipose tissue drives insulin resistance, which raises ovarian androgens.
Hyperinsulinemia feeds the ovary
Excess insulin amplifies LH-driven theca-cell androgen output.
The anovulation cycle
High androgens block follicle maturation, halting ovulation.
GLP-1 Agonist Start — Appetite Suppression Begins
Semaglutide and liraglutide slow gastric emptying and blunt hunger signals.
- GLP-1 RA: Drug class (sema / lira)
- 2–4 wks: Weight loss onset (first measurable drop)
- ↓ 20–30%: Caloric intake (reported average)
- 4–8 wks: Dose titration (to target dose)
Central appetite signaling
GLP-1 receptors in the hypothalamus dampen hunger drive.
Gastric emptying slows
Delayed stomach emptying prolongs fullness after meals.
Early metabolic shift
Modest early weight loss starts improving glucose handling.
5–10% Body Weight Reduction Over Months
Sustained weight loss meaningfully lowers visceral and ovarian fat signaling.
- 5–10%: Target loss (clinically meaningful)
- 3–6 mo: Time to target (typical trajectory)
- ↓ ~20%: Visceral fat drop (disproportionate loss)
- ↓ 4–8 cm: Waist circumference (average reduction)
Visceral fat falls first
Metabolically active visceral fat shrinks faster than subcutaneous.
Adipokine profile shifts
Falling leptin and rising adiponectin ease insulin resistance.
A threshold effect
Reproductive benefits accelerate past ~5% total loss.
Insulin Sensitivity Improves as Adiposity Falls
Reduced fat mass lowers circulating insulin, easing pressure on the ovary.
- ↓ 30–50%: HOMA-IR (typical improvement)
- ↓ significantly: Fasting insulin (vs baseline)
- ↑ rises: SHBG (binds free testosterone)
- improved: Glucose tolerance (OGTT normalizes)
Hyperinsulinemia recedes
Lower insulin reduces theca-cell androgen overproduction.
SHBG rebounds
Liver makes more SHBG, binding up free testosterone.
A virtuous cycle begins
Better insulin sensitivity further supports weight loss.
Ovulatory Cycles Restored, Androgens Normalize
Lower insulin and androgens let follicles mature and ovulation resume.
- 8–12/yr: Ovulatory cycles (from 0–4 at baseline)
- normalized: Free testosterone (within reference range)
- ↑ increases: Spontaneous pregnancy (reported in cohorts)
- restored: Menstrual regularity (in majority responders)
Follicle maturation resumes
Normalized hormones let a dominant follicle develop fully.
Regular cycles return
Monthly ovulation replaces sporadic, unpredictable cycles.
Durability depends on maintenance
Benefits persist only while weight loss is sustained.