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Fasting Insulin

INS - Fasting Insulin. Detects early insulin resistance before blood sugar or HbA1c rise. Fasting insulin is the earliest metabolic warning sign, it can be elevated 10-15 years before a diabetes diagnosis. Requires clinic visit.

INSU
Cardiometabolic
Measured in pmol/L

What It Measures

Fasting Insulin measures the amount of the hormone insulin circulating in your blood after you have not eaten for a period of at least eight to twelve hours. Insulin is produced by the beta cells of your pancreas and acts as a master key that unlocks your cells so they can absorb glucose (sugar) from the bloodstream and use it for energy. Measuring insulin in a fasted state is particularly valuable because it can reveal early signs of metabolic imbalance, often years or even a decade before changes show up on standard blood sugar or HbA1c tests. This is why fasting insulin is sometimes described as the earliest warning light on your metabolic dashboard. When your body is working well, a small amount of insulin is sufficient to keep blood sugar neatly controlled.

However, if your cells start becoming less responsive to insulin, a state known as insulin resistance, your pancreas compensates by producing more of it. For a while, this extra insulin keeps blood sugar levels looking perfectly normal on routine tests, but behind the scenes the pancreas is working overtime. Think of it like a thermostat in your home: if the insulation starts deteriorating, the boiler has to fire more frequently to maintain the same temperature. Everything feels fine inside, but the energy bill (your insulin level) tells the real story. Over time, if insulin resistance continues to progress, the pancreas may eventually struggle to keep up, and blood sugar levels begin to rise.

Catching things at the insulin stage, before blood sugar is affected, gives you the widest possible window to make meaningful lifestyle changes. Your fasting insulin level is influenced by several factors, with diet being one of the most significant, particularly your intake of refined carbohydrates and sugars. Body weight, especially excess fat around the midsection, physical activity levels, sleep quality, stress, and genetics all play important roles. The reassuring news is that insulin resistance is often highly responsive to lifestyle changes including regular exercise, dietary adjustments, improved sleep, and weight management. If your fasting insulin is higher than expected, your GP can help you understand the result in context and work with you on a practical plan to support your metabolic health going forward.

What Your Results Mean

Low

Below Range

A low insulin level may indicate that your pancreas is producing less insulin than expected. This can be a normal finding in people who eat a low-carbohydrate diet. If you have any concerns about your blood sugar management, your GP can discuss this in the context of your glucose and HbA1c results.

Normal

Within Range

Your insulin level is within the healthy range, which suggests your pancreas is producing an appropriate amount of insulin to manage your blood sugar. This is a positive indicator of your metabolic health.

High

Above Range

A raised fasting insulin level suggests your body is producing more insulin than usual to keep blood sugar under control, a pattern known as insulin resistance. Left unaddressed, insulin resistance can progress over time and increase the risk of metabolic conditions including type 2 diabetes. The important thing to know is that insulin resistance is often highly responsive to lifestyle changes, including regular physical activity, reducing refined carbohydrates, improving sleep, and managing weight. Discuss this result with your GP, who can assess your broader metabolic picture and work with you on a plan to address it.

See where your Fasting Insulin sits

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