Educational information only. At Precursor, blood testing is requested and reviewed by a clinician and considered alongside your history and other markers, not as a stand-alone diagnosis. Testing is performed in NATA-accredited laboratories to ISO 15189 standards.
What is fasting insulin?
Insulin is the hormone that lets your cells take up glucose from the blood. Fasting insulin measures how much your body is producing at rest, after an overnight fast. It is a more sensitive early marker than glucose, because the body will often ramp up insulin to keep blood sugar normal long before glucose itself starts to rise.
Why it matters
Because insulin rises first, fasting insulin can reveal insulin resistance at an earlier, more reversible stage than fasting glucose alone. This makes it a valuable marker for understanding metabolic health before more obvious changes appear, which is why it features in more thorough metabolic assessments.
What your results can mean
Higher than optimal
A raised fasting insulin suggests the body is working harder to keep blood sugar in check, a hallmark of early insulin resistance. It is read alongside glucose, and the two together can be used to estimate insulin sensitivity.
Within the healthy range
A lower fasting insulin generally indicates that your body is managing blood sugar efficiently without excess effort, a favourable sign of metabolic health.
Reference ranges in Australia
Fasting insulin is reported in milli-international units per litre (mIU/L), with reference ranges that vary between laboratories and assays. Lower-to-mid range values are generally considered more favourable. Read your result against the range on your own report and alongside your glucose.
Test your fasting insulin with Precursor
Fasting insulin is most powerful read together with glucose. At Precursor it is measured as part of Full Advanced Bloods, a single clinician-reviewed blood draw covering your metabolic, heart, hormonal, kidney, liver, thyroid and nutrient markers together, giving you and your clinician an early, sensitive view of your metabolic health and a baseline to track.
