IGF-1
Also called Insulin-like growth factor 1, somatomedin C
IGF-1 (insulin-like growth factor 1), also called somatomedin C, is a hormone that carries out many of the effects of growth hormone in the body. Together, growth hormone and IGF-1 support the normal growth of bones and tissues, and growth hormone also helps regulate metabolism.
Growth hormone itself is released in pulses, so a single growth hormone reading can be high or low depending on when the blood was drawn. IGF-1 stays far steadier through the day, which is why an IGF-1 blood test is the usual way to gauge growth hormone activity. It is used to detect and monitor growth hormone disorders, including growth hormone deficiency and acromegaly, a condition of excess growth hormone in adults.
Why it matters after 45
IGF-1 and growth hormone rise through childhood, peak at puberty and decline through adulthood, so a result has to be read against an age-matched range. In midlife, IGF-1 comes up most often as the lab marker discussed alongside therapies that act on the growth hormone system, where the page for that treatment explains how the marker is used.
Where it comes up
Related terms
References
- MedlinePlus. IGF-1 (Insulin-like Growth Factor 1) Test. U.S. National Library of Medicine. https://medlineplus.gov/lab-tests/igf-1-insulin-like-growth-factor-1-test/
- MedlinePlus. Growth Hormone Tests. U.S. National Library of Medicine. https://medlineplus.gov/lab-tests/growth-hormone-tests/
- MedlinePlus. Growth hormone test. Medical Encyclopedia. https://medlineplus.gov/ency/article/003706.htm
Definitions here are educational and are not medical advice. They explain what a term means; the pages linked above cover what it means for you, and a clinician reviews your own results. Editorial & medical review policy · All glossary terms