Educational information only. At Precursor, hormone 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 IGF-1?

IGF-1, or insulin-like growth factor 1, is a hormone produced mainly by the liver in response to growth hormone. Because it is more stable in the blood than growth hormone itself, IGF-1 is used as a practical marker of your overall growth-hormone activity.

Why it matters

IGF-1 reflects the growth-hormone axis, which influences tissue growth, repair and metabolism. It is used clinically to assess conditions of growth-hormone excess or deficiency, and it naturally changes across the lifespan, being highest in youth and declining with age.

What your results can mean

Higher than expected

A high IGF-1 can reflect excess growth-hormone activity and prompts a clinician to look further. It is always interpreted against your age.

Lower than expected

A low IGF-1 can reflect reduced growth-hormone activity, nutrition or other factors, and naturally declines with age. It is read within the broader clinical picture.

Reference ranges in Australia

IGF-1 is reported in nanomoles per litre (nmol/L) or micrograms per litre, and reference ranges are strongly age-dependent. For this reason your result is always read against an age-matched range. Read your result against your own report and with a clinician.

Understanding your hormones with Precursor

IGF-1 must be read against your age to mean anything. At Precursor, hormone testing is requested and reviewed by a clinician, so your result is interpreted appropriately. If this is something you would like to understand, you can speak with Precursor's clinical team about whether testing is right for you.