How High Insulin Disrupts Ovulation (Even If Your Blood Sugar Looks “Normal”)

When most women think about hormones and fertility, they picture oestrogen, progesterone, or maybe thyroid.
But there’s another hormone quietly working behind the scenes that can completely throw off ovulation — and it’s probably not one your GP is checking closely enough.

Enter: insulin.

Insulin isn’t just about blood sugar

We tend to think of insulin as the “sugar hormone,” the one that keeps your glucose in check after a meal. And it is, but it’s so much more than that. It’s also a major hormone communicator.
It talks directly to your ovaries, adrenals, thyroid, and brain, and when it’s chronically elevated (aka insulin resistance), that delicate hormonal conversation gets messy.

Your hypothalamus and pituitary — the two master hormone messengers in your brain — rely on precise feedback from insulin to decide how much oestrogen, progesterone, FSH, and LH to release.
When insulin is high, those signals become scrambled. The result? Your ovaries can’t quite hear what the brain is asking for, and ovulation either becomes delayed… or doesn’t happen at all.

High insulin = high testosterone

Here’s where things really start to go sideways.

When insulin levels are consistently high, it tells the theca cells in your ovaries to pump out more testosterone. At the same time, your liver makes less of a protein called SHBG (sex hormone binding globulin) — which means there’s more free testosterone floating around in your bloodstream.

That combo leads to:

• Follicles that start to grow but never finish maturing

• Irregular or absent ovulation

• Oily skin, cystic acne, unwanted hair growth

• And in some cases, cystic-appearing ovaries (even without full-blown PCOS)

Essentially, your ovaries get “stuck” mid-cycle — like they’re trying to ovulate but can’t quite get there.

It also throws off your FSH:LH ratio

To ovulate properly, your body needs a steady rise in FSH (follicle-stimulating hormone) early in the cycle.
But when insulin and androgens are high, your brain increases LH (luteinising hormone) instead.

Too much LH and not enough FSH = follicles that can’t finish maturing and release an egg.
You end up with an ovary that’s hormonally confused — it’s making hormones, but not the right ones, in the right amounts, at the right time.

Low progesterone and a weak luteal phase

Even if you do ovulate, high insulin often means your corpus luteum (the little gland that forms after ovulation) is weak and short-lived.
That leads to low progesterone, the hormone that stabilises your luteal phase and helps an embryo implant successfully.

Without enough progesterone, you can experience:

• Short cycles

• Spotting before your period

• PMS

• Difficulty conceiving

• Or early miscarriage

So if you’ve been told your blood sugar looks “fine” but you’re still not ovulating regularly or your luteal phase is short — insulin resistance may still be playing a hidden role. Glucose levels can look relatively normal but insulin can be quietly increasing in the back ground. 

Aim for a glucose levels <5 and an insulin between 4-8. Tested fasted always. No exceptions. 

How to support blood sugar naturally

The good news? Insulin resistance can be improved — often dramatically — with a few targeted changes.

Here are my favourite ways to bring insulin (and ovulation) back into harmony:

• Eat more fibre-rich foods – think apples, chia seeds, flaxseeds, blueberries. Fibre slows glucose absorption and feeds your gut microbes that help regulate blood sugar.

• Add 1 tbsp apple cider vinegar in a tall glass of water daily (preferably before your main meal) to improve insulin sensitivity.

• Include both Myo-inositol and D-chiro inositol — these nutrients help restore normal ovarian insulin signalling.

• Incorporate strength training a few times per week to build muscle and improve glucose uptake.

• Hydrate with electrolytes – I love SODII for this.

• Use herbs strategically – Gymnema for sugar cravings, cinnamon and fenugreek to improve insulin sensitivity, and berberine (if tolerated) as a potent natural insulin modulator.

• Add in sodium butyrate – a short-chain fatty acid that supports gut and metabolic health.

The takeaway

Insulin resistance isn’t just about blood sugar or weight — it’s about communication.
When insulin is high, the conversation between your brain and ovaries gets distorted, and ovulation either doesn’t happen or happens poorly.

The result? Irregular cycles, low progesterone, and difficulty conceiving — even if your glucose looks “normal.”

Love Megan