A plain-language, continually updated guide from Dr. Matt Chalmers’ clinical reference on hormones and peptides.
Insulin is a hormone produced by your pancreas that signals cells throughout the body to take up glucose from the blood. Its importance goes well beyond blood sugar management alone — insulin resistance is one of the most far-reaching, underappreciated disruptors of hormone health we see, touching everything from testosterone and PCOS to nutrient absorption at the cellular level.
Here’s a connection that’s often missed: the same receptors your cells use to take up glucose (called GLUT4) also depend on insulin signaling to pull in key nutrients like zinc, selenium, and magnesium. That means the more insulin-resistant someone becomes, the fewer of these critical nutrients actually make it into their cells — regardless of how much they’re eating or supplementing. This is a major, often-overlooked driver of nutrient deficiency in people with metabolic dysfunction.
In men, insulin resistance produces a characteristic pattern of low testosterone, elevated estrogen, and suppressed pituitary signaling. In women, the picture is more complex and can go the opposite direction: insulin resistance drives excess ovarian androgen production, which is central to PCOS (polycystic ovary syndrome), while simultaneously interfering with ovulation. Addressing insulin resistance directly — and then making sure the resulting nutrient deficiencies are corrected — is often the fastest path to meaningfully improving PCOS symptoms.
Video summary: Insulin resistance is linked to type 2 diabetes, weight gain, sleep apnea and a higher risk of cognitive decline, and fasting insulin is one of the most useful lab tests for spotting it early. As cells become less responsive to insulin, the body releases more and more of it to keep blood sugar normal, so fasting insulin often rises years before blood sugar or A1c does. Dr. Chalmers asks patients to make sure fasting insulin is part of their routine labs. In his practice, a fasting insulin around 10 or higher is treated as an early warning sign and a cue to start working on bringing it down, ideally with a provider’s guidance.
Insulin is FDA-approved as a prescription therapy for diabetes. Evaluation of insulin levels and sensitivity is done through lab testing with our providers.
Insulin resistance is documented to disrupt sex hormone balance in both men and women (through different mechanisms), interfere with nutrient uptake at the cellular level, and precede a diabetes diagnosis by years. This connective role across so many other hormone symptoms is the physiological basis for the insulin-focused approach used throughout this practice’s metabolic protocols.
Insulin is FDA-approved prescription therapy for diagnosed diabetes; our practice’s focus is more often on evaluating and improving insulin sensitivity through metabolic protocols rather than administering insulin itself. Evaluation and any therapy decisions are made through lab testing and individualized care with our providers.
Insulin resistance is the central focus of our Metabolic Reset program — learn how we approach it, and what conditions it’s linked to.
This page draws on The Pillars Path: A Root-Cause Guide to Hormones, Peptides, and Metabolic Health by Dr. Matt Chalmers — Pillars of Wellness’ clinical reference on hormone and peptide therapy.
