PCOS and Insulin Resistance: Why It Happens, Testing and Treatment
Medically reviewed by Sabeen Munib M.D.Insulin resistance is part of PCOS itself, so it can affect women at any weight, not only those with extra pounds. High insulin pushes the ovaries to make more testosterone, which can make periods less regular and acne or unwanted hair worse. A glucose test, not a fasting insulin level, is how it is checked, and treatment usually starts with activity and eating habits, with metformin or a GLP-1 medicine as options for some women.
Why does PCOS cause insulin resistance?
Most women with PCOS have some degree of insulin resistance. It is built into how the condition works, and it is not caused by anything you did. Extra weight can make it stronger, but it is often present in lean women with PCOS too.
When your body does not respond well to insulin, the pancreas makes more of it. That extra insulin affects your hormones in two ways:
- It signals the ovaries to make more androgens, such as testosterone
- It lowers a protein called SHBG, which normally holds testosterone in check, so more of it is free to act
More active androgen can mean irregular or missed periods, acne, extra hair on the face or body, and thinning hair on the scalp. This is why treating insulin resistance can help PCOS symptoms, not only blood sugar.
Can you have PCOS insulin resistance if you are thin?
Yes. Lean PCOS is common, and insulin resistance can still be present. Many women at a healthy weight are told their PCOS cannot be metabolic, but it can. That is why every woman with PCOS should have her blood sugar checked, whatever she weighs.
What are the signs of insulin resistance in PCOS?
Often there are no clear signs. When there are, look for:
- Dark, velvety skin on the back of the neck, underarms or groin
- Skin tags
- Weight that builds around the waist, or is hard to lose despite effort
- Periods that get further apart or stop
- Acne or unwanted hair that is getting worse
- A family history of type 2 diabetes, or diabetes during a past pregnancy
None of these prove insulin resistance on their own, and their absence does not rule it out. A blood test gives the real answer.
How is insulin resistance tested in PCOS?
The goal is to check what insulin resistance is doing to your blood sugar. A fasting insulin level or HOMA score is not recommended in routine care, because results vary between labs and do not reliably guide treatment.
These are the tests that matter:
- Two-hour glucose tolerance test: the most accurate test for PCOS, and preferred for women at higher risk
- A1C or fasting glucose: simpler tests that may be used for women at lower risk
- Cholesterol and triglycerides, plus a blood pressure check
Testing is done when PCOS is diagnosed, then repeated every one to three years depending on your risk. Higher risk includes a BMI of 25 or more (23 or more for Asian women), past diabetes in pregnancy, a family history of type 2 diabetes, high blood pressure, or Hispanic, Asian, African American, Indigenous or Pacific Islander background.
Planning a pregnancy with PCOS
Women with PCOS have a higher chance of diabetes during pregnancy. A glucose tolerance test is recommended before trying to conceive or starting fertility treatment, and again during pregnancy.
What helps insulin resistance in PCOS?
Healthy habits come first, and they help at any weight. They improve how your body uses insulin even before the scale moves.
Activity
- At least 150 minutes a week of moderate activity, such as brisk walking, or 75 minutes of vigorous activity
- Strength training on two days a week that are not back to back
- If you are working on weight, building up toward 250 minutes a week of moderate activity helps more
- Fewer long stretches of sitting
Eating
No single diet is proven best for PCOS. A pattern you can keep up matters more than the name of the plan:
- Vegetables, fruit, beans, whole grains, fish, nuts and lean protein
- Fewer sugary drinks, sweets and refined carbs
- Regular meals rather than strict or crash diets, which tend to backfire
If you carry extra weight, even a modest loss can make periods more regular and improve blood sugar. Sleep matters too: PCOS raises the chance of sleep apnea, and poor sleep makes insulin resistance worse.
Does metformin help PCOS insulin resistance?
Metformin is a diabetes medicine that is commonly used off-label in PCOS. It helps the body respond better to insulin and may be considered for women with insulin resistance, prediabetes or a higher BMI. It can be used alone or with birth control pills. Women at a lower BMI may also be offered it, though the effect tends to be smaller.
What to know about metformin:
- Stomach upset, nausea and loose stools are the most common side effects. Starting with a low dose, taking it with food and using the extended-release form can help
- Long-term use can lower vitamin B12, so B12 may be checked over time
- It is not used in people with severe kidney disease
Can a GLP-1 medicine help with PCOS?
GLP-1 medicines are not approved to treat PCOS itself. For women who qualify by weight and health, a brand-name GLP-1 medicine may be considered for weight, alongside healthy habits. The Pur Health offers brand-name medicines only:
- Wegovy and Zepbound: approved for weight management in people who qualify
- Ozempic and Mounjaro: approved for type 2 diabetes
These medicines are stopped before a planned pregnancy. The Wegovy label advises stopping at least two months before trying to conceive, so tell Dr. Munib if pregnancy is in your plans.
Zepbound, Mounjaro and birth control pills
Many women with PCOS take birth control pills, so this matters. The labels for Zepbound and Mounjaro say they may make birth control pills work less well. If you take the pill, switch to a non-pill method or add a backup method such as condoms for four weeks after starting and for four weeks after each dose increase. Birth control that is not taken by mouth, such as a patch, ring, IUD or implant, is not affected in the same way.
What about inositol and supplements?
Inositol is a popular supplement for PCOS, but the evidence is limited and it is not a substitute for medical care. If you take it or any other supplement, tell Dr. Munib so she can look at your full plan.
How Dr. Munib approaches PCOS and insulin resistance
Dr. Munib looks at the whole picture: your periods, skin and hair symptoms, weight history, family history, sleep and whether you want to become pregnant now or later.
She may order a glucose tolerance test or A1C, cholesterol, and hormone tests to confirm PCOS and rule out thyroid or other causes. Treatment depends on what bothers you most and on your results. Options she may discuss include habit changes, birth control pills, metformin, or a GLP-1 medicine for weight, with follow-up labs to see how things change.
Read about PCOS treatment at The Pur Health
Learn about hormone balancing and lab testing
See weight loss options, including brand-name GLP-1 medicines
When should you see a doctor?
- Your periods come more than 35 days apart, or you have gone three months without one
- You have new dark velvety skin patches, fast-growing facial hair or sudden hair loss
- You have trouble getting pregnant
- You are very thirsty, urinating often or losing weight without trying
If PCOS or insulin resistance sounds familiar, a visit and a few blood tests can give you clear answers. The Pur Health is in-network with most PPO plans, and cash visits are $190 for new patients and $150 for returning patients. Book at our Irvine office at 114 Pacifica, Suite 280, or call (949) 647-5234.