Insulin resistance in menopause: the quiet metabolic shift

What insulin resistance means

Insulin moves glucose from the blood into muscle, fat and liver. Insulin resistance means those tissues respond less to the same signal, so the pancreas compensates by producing more.

For years the compensation works and blood glucose stays normal while insulin runs high. That is why the condition is silent: the measure that eventually flags it, blood glucose, is the last thing to change.

By the time fasting glucose is abnormal, the process has usually been running for a long time.

Why the transition affects it

Four routes act together, which is why the effect is larger than any one of them suggests:

• Estrogen influences insulin signalling in muscle and liver directly, and its loss reduces glucose uptake
• Fat shifts to the visceral compartment, which releases free fatty acids and inflammatory signals straight to the liver
• Muscle mass declines, and muscle is the largest site of glucose disposal in the body
• Sleep disruption reduces insulin sensitivity measurably after even short periods of restriction

How it shows up

Mostly it does not, which is the problem. Where there are signs they are non-specific: weight accumulating centrally despite no change in eating, energy dips after meals, stronger sugar cravings, and increasing difficulty losing weight with approaches that used to work.

Acanthosis nigricans — darkened, velvety skin in the neck folds, armpits or groin — is a genuine physical sign of significant insulin resistance and is worth showing a clinician rather than treating as a skin complaint.

What to measure

HbA1c reflects average glucose over roughly three months and is the standard screen. It identifies prediabetes, the stage where intervention is most effective.

Fasting glucose is useful but insensitive early on. Fasting insulin, and calculations derived from it, can reveal resistance earlier, though they are less standardised and not routinely offered.

Waist circumference correlates with visceral fat and adds real information to any of them. Triglycerides and HDL together also carry a signal: raised triglycerides with low HDL is a recognisable pattern.

What acts on it

Resistance training increases glucose uptake into muscle both acutely and by preserving muscle mass, which is why it appears in guidance ahead of further energy restriction at this age.

Treating sleep disruption matters more than its reputation suggests, and untreated obstructive sleep apnoea will limit what anything else achieves.

Hormone therapy has been associated with improved insulin sensitivity and lower incidence of type 2 diabetes in trial data, but it is not prescribed for this purpose and is not a diabetes prevention treatment.

When to see someone

Ask for HbA1c, lipids, blood pressure and waist circumference together at a midlife review. Prediabetes is common, silent, and the stage at which action has the greatest effect.

Raise it sooner with a history of gestational diabetes, polycystic ovary syndrome, or a family history of type 2 diabetes, all of which raise risk and none of which are routinely asked about in a menopause consultation.