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No. IGF-1 is not a steroid hormone. IGF-1, or insulin-like growth factor 1, is a peptide hormone made primarily in the liver in response to growth hormone.
Written and medically reviewed by David Nazarian, MD — Board Certified in Internal Medicine.
How IGF-1 Differs From Steroid Hormones
Steroid hormones such as testosterone, estrogen and cortisol are derived from cholesterol and can enter cells to interact with intracellular receptors. IGF-1 is a peptide hormone that binds to receptors on the cell surface and triggers intracellular signaling pathways.
What Does IGF-1 Do?
IGF-1 plays an important role in childhood growth and also contributes to tissue maintenance and metabolism in adults. It is part of the growth-hormone/IGF-1 axis and should not be viewed as a general performance-enhancing or anti-aging hormone.
Why Is IGF-1 Tested?
Clinicians may order IGF-1 when evaluating suspected growth-hormone excess or deficiency. Because growth hormone is released in pulses, IGF-1 can provide a more stable marker of overall growth-hormone activity.
Is IGF-1 Used for Bodybuilding?
Use for bodybuilding or physique enhancement is not an established medical indication. Prescription recombinant IGF-1 has specific approved medical uses, and unapproved products marketed online may have uncertain identity, potency and safety.
Does a High IGF-1 Mean Better Health?
No. Hormone levels should be interpreted within age-appropriate reference ranges and clinical context. Excessive growth-hormone/IGF-1 signaling can occur in diseases such as acromegaly and is not a desirable target.
Learn more about IGF-1 testing and therapy, hormone testing, and growth hormone deficiency evaluation. If abnormal IGF-1 or growth-hormone symptoms need interpretation, schedule a physician-led evaluation.
