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The Insulin-PCOS Connection

Updated: Jan 16

by Dr. Mitchell Rasmussen, DC, CFMP, FRC-ms

Most of the people we see who’ve been given a diagnosis of Polycystic Ovarian Syndrome (PCOS) don’t even have evidence of cysts on their ovaries. I believe the name of this syndrome is mostly misleading, and completely unhelpful if this is something you’re working through in your own life.

The clinical diagnosis is technically established when a woman has two of the following three criteria:

  1. High androgens

  2. Ovulatory dysfunction

  3. Polycystic ovaries

My issue is in the breadth in potential causes of each of the above symptoms, as well as the number of potential diagnoses which these symptoms could be feeding into.

Too broad, not specific, not discerning causation.

This is why many are frustrated when dealing with some of the above symptoms, or when somebody has been diagnosed with PCOS and has been told that their only real options are drugs like Spironolactone, Metformin, or hormonal birth control. << More on the conventional treatment of PCOS >>

Understanding insulin as a primary driver of PCOS. How insulin affects hormone signaling to interrupt ovulation.

In our Functional Medicine practice, we focus more on the physiology and less on the mouth noise of labeling Polycystic Ovarian Syndrome. Then, we can help these patients start to make progress with their condition and improve their symptom picture.

Insulin Resistance: A Big Time Player in PCOS

We now have solid evidence showing insulin resistance (often because of chronic, unchecked, smoldering inflammation) as a direct CAUSE of PCOS rather than insulin resistance merely being a result or some sort of bystander effect.

I think it’s safe to say that insulin resistance (and the high insulin resulting) is the PRIMARY driver of PCOS. When it comes to this piece, let’s get into a little pathophysiology for a minute:

There is a complex set of hormones and pathways involved in female reproductive physiology.

Early in the cycle, a woman’s estrogen levels are low, and her brain signals to another part of her brain that this is the case; this leads to the brain release of Follicle Stimulating Hormone (FSH).

FSH has a job in communicating with the ovary – and getting some follicles there to turn into eggs. As this is happening, these developing follicles cause a huge increase in estrogen in the ovaries; and this is signaled back to the brain that there is a dominant egg that’s ready to be released.

Under the influence of estrogen, the brain releases Luteinizing Hormone (LH), which leads to just the dominant egg being released from the ovary >>> Viola! Ovulation has occurred!

Ovulation Simplified to show hormone signaling from the brain to the ovary. PCOS involves impaired ovulation due to hormonal imbalance.
Ovulation starts a hormonal release which tells the other follicles to degrade; and they do so. It requires lots of signals and hormones and any disruption in this system can cause problems.

OK, So What about Insulin and PCOS?!

Excessive insulin in the ovaries shuts down estrogen productionwell, conversion from testosterone really. Men and women both don’t technically MAKE estrogen. Estrogen is aromatized (via an aromatase enzyme) from testosterone. Insulin messes with this aromatase enzyme, which is going to lead to testosterone not being readily converted into estrogen.

As a result: Estrogen drops and androgens go up.

Now we have lost the mid-cycle estrogen release necessary to signal ovulation, and the ovaries retain the eggs. This can lead to buildup of partially developed follicles around the ovary which leads to the classic imaging findings consistent with a diagnosis of PCOS.

Not only that, but it appears the insulin acts directly in the brain to lower the production of LH. If we can’t release LH, we can’t properly ovulate.

The role of insulin in PCOS. Insulin inhibits conversion of testosterone to estrogen which limits brain signaling to allow ovulation.

Bottom Line: We see multiple reinforcing problems between insulin resistance and PCOS – elevated androgens, impaired hormone signaling in the brain, and loss of the regular ability to ovulate. Addressing blood sugar control, stress, and associated inflammation are paramount in the functional medicine approach to management of PCOS.


You May Also Like:

Recommended Reading on the topic of Insulin / PCOS:



Mitchell Rasmussen Functional Medicine Doctor Denver Colorado

Dr. Mitchell Rasmussen, DC, CFMP serves as Director of Functional Medicine at The Facility in Denver, CO. He sees patients in-person and via Telehealth to get to the root cause of dysfunction and restore a state of well-being using nutritional intervention, supplementation, and lifestyle change.


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Want to work with a functional medicine doctor to run labs and assess nutrient status? Struggling with hormone imbalance, IBS, weight gain, mood changes? Let's look at BIOCHEMISTRY. Read more about Functional Medicine at The Facility here.

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The PCOS and Insulin Connection: A Functional Medicine Doctor's Perspective.


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Dr. Mitchell Rasmussen - Doctor of Chiro
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