Dr. Alan Krasner
Chief Endocrinologist
If you are living with acromegaly, you’ve likely heard your healthcare provider talk about “IGF-1” during your appointments. But what exactly is IGF-1, and why is it so important to understanding and managing your condition?
IGF-1, short for Insulin-like Growth Factor-1, is a hormone produced primarily by the liver in response to growth hormone (GH). In healthy individuals, IGF-1 helps regulate normal growth and development. However, in people with acromegaly, IGF-1 levels are typically too high. Elevated IGF-1 contributes to many of the signs and symptoms of acromegaly, including enlarged hands and feet, changes in facial features, joint pain, and organ enlargement.
Measuring IGF-1 levels in the blood regularly is a routine part of long-term acromegaly care. In fact, the Endocrine Society Clinical Practice Guidelines recommend using IGF-1 testing as the primary method for assessing disease control in acromegaly. It is essential for both monitoring disease activity and guiding treatment decisions. The goal of treatment is to maintain IGF-1 levels consistently at a healthy normal level or as close to normal as possible.
Why IGF-1 Testing Matters
IGF-1 levels don’t fluctuate as much as GH levels do throughout the day, and thus the time of day blood is drawn to measure IGF-1 has little impact on test results, making it a more reliable single marker for disease activity.
When IGF-1 level is within the target range, it generally translates to fewer symptoms, improved quality of life, and reduced risk of medical problems related to acromegaly. However, sometimes patients who are on medicine for acromegaly and who appear to have IGF-1 in the normal range can still report troublesome symptoms that “break through” the medication. Clearly, additional research is needed in this area—but in the meantime, achieving target IGF-1 is a critical goal of therapy.
How IGF-1 is Measured
The laboratory tests that are used to measure IGF-1 have become more sophisticated over the years since this test was introduced into clinical practice. The ability of the test to accurately measure IGF-1 has improved and the definition of “normal” levels has also been greatly refined. The normal range for IGF-1 depends on age and sex—one group of researchers has now evaluated over 15,000 people of all ages without acromegaly to very precisely define normal test results from all ages from 0-90. As a result, we have learned over the years that the true upper limit of normal is quite a bit lower than when this test was first introduced.
In clinical practice today, the IGF-1 tests are not all the same. If you’re getting your IGF-1 measured, ask your doctor or laboratory which test is being used and keep track of this. It is best to use the same laboratory using the same method to compare results as your IGF-1 is measured periodically.
A great resource to learn more about this is CrinetiCare.com – your doctor can even order a free test for you here.
Tracking Your IGF-1 Over Time
Monitoring IGF-1 is not a one-time event—it’s something that needs to be done regularly to ensure your treatment remains effective. Whether you are on medication, have undergone surgery, or are being monitored post-treatment, periodic IGF-1 testing helps determine if your current approach is working or needs adjustment.
If your levels are above target, your doctor may recommend changing your treatment plan. This could mean adjusting your medication dose, switching therapies, or considering additional interventions. The key is to have an open dialogue with your healthcare team and to be proactive in understanding your lab results.
What You Can Do as a Patient
- Keep a record of your IGF-1 results over time to track progress.
- Ask your doctor what your most recent IGF-1 level is and how it compares to the target.
- Inquire about the IGF-1 test and laboratory used to feel more confident in comparing your results to previous results.
- Be proactive about scheduling routine IGF-1 tests as recommended by your health care provider.
In Summary
IGF-1 is more than just a number—it’s a powerful indicator of how well your acromegaly is being managed. By understanding your IGF-1 levels and actively engaging in your care, you can take important steps toward improving your health and quality of life.
Talk to your healthcare provider today about your IGF-1 level. It’s one of the best tools we have for putting you in control of your condition.
What is acromegaly?
Acromegaly is a rare, chronic disease that is almost always caused by a pituitary adenoma that secretes excess growth hormone (GH), resulting in hypersecretion of IGF-1, predominantly by the liver. Prolonged exposure to increased levels of IGF-1 and GH leads to progressive and serious complications, including: bone, joint, cardiovascular, metabolic, cerebrovascular, and/or respiratory disease.