PCOS is usually described by what you can see: irregular cycles, acne, unwanted hair growth, difficulty conceiving. Those are real, and they are the reason most women seek help. But they are downstream effects.
For the majority of patients, the driver underneath is insulin resistance.
The mechanism
When cells resist insulin, the pancreas compensates by producing more of it. That excess insulin does two things in the ovary.
First, it stimulates the theca cells to produce more androgens — testosterone and its relatives. Second, it suppresses the liver's production of sex hormone binding globulin, the protein that keeps androgens bound and inactive. Less binding globulin means more free, active androgen circulating.
Elevated free androgen is what interrupts ovulation, drives acne and hirsutism, and produces the ovarian appearance the condition is named after.
So the visible symptoms trace back to insulin. That is why treating them individually — a pill for the cycle, a cream for the skin — manages the presentation without touching the cause.
Not every case is the same
Roughly 70–80% of PCOS presents with insulin resistance, but there is a lean phenotype where insulin is largely normal and the driver is more adrenal or inflammatory in origin. That distinction matters clinically, because the treatments diverge. Assuming all PCOS is insulin-driven is as much a mistake as ignoring insulin altogether.
This is why a proper workup measures rather than assumes: fasting insulin and glucose, a full androgen panel, LH and FSH, AMH, thyroid function, and often a CGM.
What actually helps
Correcting insulin sensitivity. Where insulin resistance is present, this is the highest-leverage intervention available. Resistance training, post-meal movement, protein-forward meals and sleep all move it. So does modest fat loss — but the fat loss is a consequence of improved sensitivity as much as a cause.
Inositol. Myo-inositol, often combined with D-chiro-inositol, has reasonable evidence for improving insulin sensitivity and ovulation rates, with a mild side-effect profile.
Metformin, when indicated. Useful in clear insulin resistance, particularly where fertility is a goal. Not automatic, and not a substitute for the above.
Treating the thyroid. Hypothyroidism and PCOS coexist often enough that it should always be checked; untreated, it worsens everything else.
Addressing sleep and stress. Both raise cortisol, and cortisol worsens insulin resistance directly.
What does not help
Aggressive caloric restriction is counterproductive in PCOS more often than in other conditions. It raises cortisol, reduces thyroid conversion, costs muscle mass — and muscle is the tissue doing the glucose clearing. Patients frequently arrive having been told for years to simply eat less, having done exactly that, and having got worse.
Weight-centric advice also misses the lean phenotype entirely.
The reframe
PCOS cannot be cured. But when the metabolic driver is identified and corrected, the reproductive symptoms very often follow: cycles regularise, androgen symptoms settle, and fertility improves.
The condition is better understood as a metabolic disorder with reproductive consequences than a reproductive disorder with metabolic side effects. That single reordering changes where treatment should start.
Dr. Farooqui Amtul leads women's metabolic health at the clinic, with a focus on PCOS, thyroid disease and gestational diabetes.