How well your body’s cells respond to insulin; higher sensitivity is better.
What insulin sensitivity means
Insulin is the hormone that signals cells to take up glucose from the blood. Insulin sensitivity describes how readily cells respond to that signal. When sensitivity is high, the body needs only a little insulin to keep blood glucose under control. When sensitivity is low, the situation is called insulin resistance, and the body has to make more insulin to keep glucose normal. It helps to think of sensitivity and resistance as two ends of the same scale: the lower the sensitivity, the higher the degree of resistance. You can read more on the insulin resistance page.
Why it matters for PCOS
Many women with PCOS have low insulin sensitivity, though not all do. The higher insulin levels that follow can push the ovaries to make more androgens and lower the protein that binds hormones, which can contribute to irregular cycles, acne, and excess hair growth. Low sensitivity is also often linked with other longer-term metabolic risks. For this reason, insulin sensitivity is often discussed as an important part of the metabolic picture in PCOS, as explained in what is PCOS.
How it is assessed
No single routine test measures insulin sensitivity directly. The more precise tests tend to be used in research rather than ordinary clinics. Instead, doctors usually use a combination of markers such as fasting glucose, fasting insulin, or HbA1c, and sometimes calculate HOMA-IR. Each marker gives only part of the picture, so results are interpreted alongside your symptoms, weight, and medical history rather than read in isolation. A single result outside the usual range does not necessarily mean something serious on its own.
When to talk to a doctor
Insulin sensitivity can change over time and is shaped by many factors, such as physical activity, eating patterns, and sleep. If you have signs such as irregular cycles or androgen signs, a doctor can assess whether metabolic testing is right for you. Any decision about testing, medicine, or major lifestyle changes is best discussed with a doctor based on your own situation, rather than on one value alone.
This glossary is education, not diagnosis. For your own situation, ask a doctor or pharmacist.