Insulin-like Growth Factor 1 (IGF-1) is produced by the liver in response to human growth hormone (HGH) and serves as the most accurate proxy for measuring growth hormone activity in the body. Unlike HGH itself — which spikes and fluctuates throughout the day — IGF-1 remains relatively stable in the bloodstream, making it the preferred marker for evaluating growth hormone status.
The IGF-1 blood test is ordered for several reasons:
- Growth hormone deficiency in adults — symptoms include fatigue, muscle loss, increased body fat, and reduced quality of life
- HGH replacement therapy monitoring — tracking IGF-1 is essential for patients on growth hormone treatment
- Acromegaly screening — a condition caused by excess growth hormone, often from a pituitary tumor
- Anti-aging and longevity optimization — IGF-1 is a key marker in comprehensive longevity panels
- Unexplained muscle loss or body composition changes in adults
Low IGF-1 in adults may indicate growth hormone deficiency. High IGF-1 may suggest excess growth hormone production. Both warrant follow-up with a physician.
Physician order included. No insurance or referral required. Results through Labcorp in 24–48 hours.
The IGF-1 blood test measures the level of insulin-like growth factor 1 in the blood. IGF-1, also known as somatomedin C, is a hormone produced in the liver in response to growth hormone (GH) secretion from the pituitary gland. Checking IGF-1 is an important part of screening for growth disorders and GH deficiency.
📅 Last Updated: May 2026 | 🩺 Medically Reviewed by: Edward Salko, D.O., Medical Director | 🧪 Lab Partner: Labcorp
What Does the IGF-1 Test Measure?
IGF-1 promotes tissue growth, cellular replication and regeneration throughout the body. About 70% of IGF-1 in the circulation is dependent on GH stimulation of its production. Low IGF-1 along with low GH indicates inadequate growth hormone.
There are two types of IGF-1 blood tests:
- Total IGF-1 – Measures both bound and unbound IGF-1 levels.
- Free IGF-1 – Specifically measures the active or unbound form of IGF-1.
Both total and free IGF-1 decline with age. IGF-1 levels are a useful tool for evaluating growth problems in children and GH deficiency in adults when used in combination with provocative GH stimulation testing.
Who Should Have IGF-1 Testing?
Checking IGF-1 levels is recommended for:
- Adults with suspected pituitary disease or hormone deficiencies
- Diagnosing causes of abnormal growth – too fast or too slow
- Monitoring IGF-1 treatment for growth disorders
- Assessing effectiveness of GH replacement therapy
Measuring IGF-1 helps determine if poor growth or GH deficiency is due to inadequate IGF-1 response or GH resistance.
Preparing for the IGF-1 Blood Test
No special preparation is necessary. The blood draw is done in the morning after fasting overnight because IGF-1 levels fluctuate during the day with food intake. Certain medications may impact test results, so it is important to tell your doctor about any drugs you are taking.
Understanding IGF-1 Test Results
Normal IGF-1 ranges are age and gender specific. In general, acceptable IGF-1 levels are:
- Teens: 170-500 ng/mL
- Adults: 117-329 ng/mL
The endocrinologist will interpret your IGF-1 result based on your medical history, symptoms and other lab results. An abnormal IGF-1 level may require additional GH testing to confirm a growth or pituitary disorder before starting treatment.
Accessing IGF-1 Testing Near Me
Our extensive national lab network provides easy access to IGF-1 testing across the U.S. Order your test online and get same-day blood draw at one of 4,000+ locations. We work with top labs like Quest Diagnostics to make IGF-1 testing affordable and convenient. Results delivered through our secure portal within 1-3 days.
Tests Included:
Estimated Turn Around For Results:
2-10 Business Days
For an exact turnaround time for results, please contact us at Personalabs and we will contact the lab on your behalf as turnaround times vary depending on testing location or lab testing provider.
Frequently Asked Questions
What does the IGF-1 test measure? IGF-1 (Insulin-like Growth Factor 1) is a hormone produced by the liver in response to human growth hormone (HGH). Because HGH fluctuates significantly throughout the day, IGF-1 is used as a stable, reliable proxy for measuring overall growth hormone activity in the body.
Who should order the IGF-1 test? The IGF-1 test is commonly ordered by adults experiencing unexplained fatigue, muscle loss, or body composition changes; patients on HGH replacement therapy who need to monitor their levels; people pursuing anti-aging or longevity optimization panels; and physicians investigating suspected growth hormone deficiency or excess (acromegaly).
What does a low IGF-1 result mean? Low IGF-1 in adults may indicate growth hormone deficiency, which can cause fatigue, reduced muscle mass, increased body fat, and decreased quality of life. Results should be reviewed with a physician who can evaluate clinical symptoms alongside lab values.
What does a high IGF-1 result mean? Elevated IGF-1 may indicate excess growth hormone production, sometimes associated with a pituitary tumor (acromegaly). If your result is significantly above the normal range, follow-up with a physician is recommended.
Do I need a doctor’s visit to order this test? No. Personalabs provides a physician-approved lab order with every purchase. No referral or insurance needed. Results in 24–48 hours through Labcorp.
