Insulin Resistance in Women: The Signs That Come First

"My bloods came back normal, so it is not that."

I hear this constantly, and it is one of the most expensive sentences in women's health, because for insulin resistance it is very often wrong. Not because the blood test was done badly, but because the standard tests are designed to catch the end of the story and this condition takes about a decade to get there.

Which means there is a long window where something is genuinely going on, the numbers look reassuring, and a woman is told she is fine while feeling nothing of the sort.

What insulin resistance actually is

Insulin is the hormone that lets glucose out of your bloodstream and into your cells, where it gets used for energy. Think of it as a key. Glucose arrives after a meal, insulin turns up with the key, the door opens, glucose goes in, blood sugar comes back down.

In insulin resistance, the lock gets stiff. The same key no longer opens the door as easily, so your pancreas does the sensible thing and sends more keys. Two, three, five times as much insulin as it used to need.

And here is the important part: for years, this works. Blood glucose stays completely normal, because the extra insulin is compensating. What is abnormal is the amount of effort your body is making to keep it there.

Eventually the pancreas cannot keep up, glucose starts to rise, and only then does a standard test flag anything. By that point the process has usually been going on for somewhere between five and fifteen years.

Why your blood test looks fine

The two tests you will normally be offered are fasting glucose and HbA1c, which is a measure of your average blood glucose over roughly the previous three months.

Both measure glucose. Neither measures insulin.

So in the compensated stage, when your pancreas is producing large amounts of insulin and successfully holding your glucose in the normal range, both tests come back normal. They are not wrong. They are answering a different question from the one you are asking.

This is why women describe going to their GP with real symptoms, being tested, being told everything is fine, and leaving with the strong sense that something has been missed. Something has, but not through carelessness. The test that would have found it is not routinely offered.

Related reading: Insulin resistance shows up on your face before it shows up on a blood test, and the connection is more direct than most people expect: Blood Sugar, Insulin and Skin Ageing.

The early signs, roughly in the order they turn up

The three o'clock crash. Energy falls off a cliff two to three hours after eating, particularly after a carbohydrate-heavy lunch. Not gentle tiredness. A real drop, often with irritability or difficulty concentrating attached.

Hungry again far too soon. You ate a proper meal and you are looking for food ninety minutes later. High insulin lowers blood glucose efficiently and then keeps going, and low blood glucose is a powerful reason to eat.

Waist measurement increasing while the scales barely move. Weight redistributing towards the middle is one of the earliest changes and one of the most useful, because you can measure it yourself. For women, a waist over 80cm is associated with increased metabolic risk, and over 88cm with substantially increased risk. Measure at the narrowest point, standing, having breathed out normally rather than held it in.

Skin tags, particularly on the neck, eyelids, or under the arms. These are strongly associated with insulin resistance and almost nobody knows it. If you have developed several in your forties, that is genuinely useful information.

Dark, velvety patches of skin in the folds of the neck, the armpits, or the groin. This has a name, acanthosis nigricans, and it is one of the clearest visible indicators of high circulating insulin. It gets mistaken for dirt or poor washing with distressing regularity.

Cravings for something sweet after every meal, even a large one.

Blood pressure creeping upwards in your forties without an obvious explanation.

None of these is diagnostic alone. Four of them together, in a woman in her forties, would have my full attention.

What supports blood sugar stability:

Why this arrives at perimenopause for so many women

Three things happen at once in the forties, and they point the same way.

Oestrogen supports insulin sensitivity. As oestrogen becomes erratic and then declines, the same meal produces a larger blood sugar response than it did five years earlier. Nothing about your diet has changed. Your response to it has.

Muscle mass declines with age unless you are working to keep it. Muscle is where most of the glucose from a meal ends up, so losing it reduces your capacity to clear glucose from the blood. This is the single most modifiable factor on the list and the one most women are not told about.

Sleep gets worse, and poor sleep reduces insulin sensitivity measurably within a few nights. The night sweats and the 3am waking of perimenopause are not just unpleasant. They have a metabolic cost.

There are also groups at higher risk regardless of age. If you have polycystic ovary syndrome, insulin resistance is part of the condition for the majority of women who have it. If you had gestational diabetes in a pregnancy, your long-term risk is meaningfully higher and this is frequently not communicated clearly after the birth. If either applies to you, do not wait for symptoms.

What to ask for

Take these to your GP, and take a list of your symptoms with you rather than relying on remembering them in a ten minute appointment.

HbA1c and fasting glucose. Standard, and still useful as a baseline even though they will likely be normal.

A full lipid panel including triglycerides and HDL cholesterol. This is the underused one. The ratio between triglycerides and HDL is a reasonable practical indicator of insulin resistance, and it is available on a test your GP already orders routinely. A rising triglyceride level with a falling HDL, in a woman with normal glucose, is a pattern that deserves attention.

Fasting insulin, if you can get it. This is the test that would actually answer the question. It is not routinely available on the NHS for this purpose, which is frustrating but is the reality, so it may need to be done privately. Combined with fasting glucose it gives a calculated measure of insulin resistance.

Blood pressure and waist circumference. Both free, both informative, both frequently skipped.

What actually improves it

The good news, and it is genuinely good, is that insulin resistance responds well to the right things, and faster than most people expect.

Resistance training is the highest-return change available. Muscle takes up glucose from the blood, and it does so through a route that does not require insulin at all during and after exercise. More muscle means more capacity to clear glucose. Two sessions a week, using weights heavy enough that the last few repetitions are difficult, changes insulin sensitivity in a way that no amount of gentle cardio matches.

Walk after meals. Ten to fifteen minutes after eating lowers the glucose peak from that meal noticeably. It is the highest ratio of benefit to effort in the whole of metabolic health.

Protein and fibre before the carbohydrate, within the same meal. Same food, different order, smaller glucose response.

Protect your sleep, for the reasons above.

Reduce ultra-processed food rather than reducing carbohydrates as a category. Whole food carbohydrates in the context of a meal containing protein and fibre are not the problem. A pastry at eleven in the morning on an empty stomach is a different proposition.

I am deliberately not putting medication in this list. There are prescription options that affect insulin resistance and they have their place, but that is a clinical conversation about your individual circumstances, not something to read about on a website and ask for by name.

If you want the whole thing assessed properly, bloods, symptoms, cycle, sleep and what to do about it, that is what a consultation at Debora Tentis Clinic is for. And if your last blood test was normal but you are still not right, bring it with you. Normal is the beginning of that conversation, not the end of it.

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Keep reading: If you are doing everything right nutritionally and the weight is not moving, insulin is one of three explanations and this covers all of them: Why You Are Eating Well and Still Not Losing Weight.

Debora Tentis is a Women's Health Pharmacist and Independent Prescriber Trainee at Debora Tentis Clinic, Milton Keynes. This post is for educational purposes only and does not constitute medical advice.