IGF-1 (LC/MS) blood test (Insulin-Like Growth Factor 1) Biomarker Testing
It measures IGF-1, a stable marker of growth hormone activity, and Vitals Vault lets you order through Quest and review results in PocketMD.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
IGF-1 (insulin-like growth factor 1) is one of the most useful blood markers for understanding your average growth hormone (GH) activity over time. Because GH itself is released in pulses, a single GH blood draw can be misleading, while IGF-1 tends to be steadier.
An IGF-1 LC/MS test measures IGF-1 using liquid chromatography–mass spectrometry (LC/MS), a method designed to improve analytical specificity. Your result is usually interpreted using age- and sex-adjusted reference ranges, because “normal” IGF-1 changes a lot across the lifespan.
This test is often used to help evaluate unexplained changes in body composition, energy, and recovery, and it is also a core lab used when a clinician is assessing possible growth hormone deficiency or excess. Your number is not a diagnosis by itself, but it can be a strong clue when paired with symptoms and follow-up testing.
Do I need a IGF-1 (LC/MS) test?
You may want an IGF-1 (LC/MS) test if you are trying to make sense of symptoms that could fit with altered growth hormone signaling, such as persistent fatigue, reduced exercise capacity, loss of lean mass, increased abdominal fat, slower recovery from training, or unexplained changes in skin and soft tissue. These symptoms are common and non-specific, so the value of IGF-1 is that it can help you and your clinician decide whether the “growth hormone axis” is worth a closer look.
This test is also commonly used when there is concern for growth hormone excess (for example, progressive changes in facial features, enlarging hands/feet, new snoring or sleep apnea, headaches, or elevated blood sugar), because IGF-1 is a recommended screening marker for acromegaly in many clinical pathways. If IGF-1 is clearly elevated for your age and sex, your clinician may order confirmatory testing rather than relying on a single lab.
If you are already on treatment that can affect growth hormone or IGF-1 (such as prescribed growth hormone, certain pituitary treatments, or some diabetes medications), IGF-1 can be used to monitor whether therapy is pushing levels too low or too high. Testing supports clinician-directed care and follow-up planning; it is not meant for self-diagnosis.
This is a CLIA laboratory blood test; results should be interpreted with your clinician because IGF-1 varies by age, physiologic state, and medical conditions.
Lab testing
Ready to order IGF-1 (LC/MS) and complete your draw at Quest?
Schedule online, results typically within about a week
Clear reporting and optional clinician context
HSA/FSA eligible where applicable
Get this test with Vitals Vault
Vitals Vault lets you order an IGF-1 (LC/MS) blood test directly, then complete your draw at a participating Quest location. You get a clear lab report plus an easy way to keep results organized for trend tracking over time.
If your result is low, in range, or high, PocketMD can help you translate the number into practical next steps to discuss with your clinician, including which companion labs often add context (like thyroid markers, liver and kidney function, glucose/insulin markers, or pituitary-related testing when appropriate).
Because IGF-1 is sensitive to age, nutrition, and health status, a single result is often the start of a conversation rather than the end. Vitals Vault makes it straightforward to retest at a sensible interval after a change in training, weight, medication, or a clinician-guided treatment plan.
- Order online and complete your blood draw at Quest
- PocketMD helps you prepare questions and interpret results in context
- Designed for trending: compare results over time in one place
Key benefits of IGF-1 (LC/MS) testing
- Gives a steadier snapshot of growth hormone activity than a single random growth hormone level.
- Helps evaluate symptoms that may relate to the growth hormone–IGF axis, such as reduced recovery, strength, or body composition changes.
- Supports screening for growth hormone excess when clinical features raise concern, with follow-up testing guided by your clinician.
- Can help assess possible growth hormone deficiency in the right clinical context, especially when paired with other pituitary evaluation.
- Provides an objective marker to monitor prescribed therapies that influence IGF-1 and avoid over- or under-treatment.
- LC/MS methodology can improve analytical specificity compared with some immunoassays, especially when results are unexpected.
- Makes it easier to trend changes after nutrition, weight, training load, or medical treatment adjustments.
What is IGF-1 (LC/MS)?
IGF-1 (insulin-like growth factor 1) is a hormone-like protein made mostly by your liver in response to growth hormone (GH) released from the pituitary gland. IGF-1 helps mediate many of GH’s longer-term effects, including support of lean tissue maintenance, bone remodeling, and metabolic signaling.
Unlike GH, which rises and falls in pulses throughout the day and night, IGF-1 tends to be more stable from hour to hour. That stability is why IGF-1 is commonly used as a practical blood marker of average GH activity.
“LC/MS” refers to liquid chromatography–mass spectrometry, an analytical technique that separates and measures molecules based on their mass. In clinical labs, LC/MS methods are often chosen to improve specificity and reduce interference compared with some antibody-based tests.
Your lab will typically compare your IGF-1 value to an age- and sex-adjusted reference range. A result that is “normal” for a 25-year-old may be high for a 70-year-old, so the reference interval matters as much as the raw number.
How IGF-1 relates to growth hormone
Growth hormone stimulates IGF-1 production, and IGF-1 feeds back to help regulate GH release. Because of this relationship, IGF-1 is often used as the first-line blood marker when clinicians are evaluating possible GH deficiency or GH excess.
Why the reference range is age-dependent
IGF-1 is highest during childhood and puberty, then gradually declines with age. That natural decline means interpretation should focus on whether your value is appropriate for your age and sex, not whether it matches someone else’s number.
What do my IGF-1 (LC/MS) results mean?
Low IGF-1 levels
A low IGF-1 result can happen when growth hormone signaling is reduced, but it can also reflect non-hormonal factors such as inadequate calorie or protein intake, significant recent weight loss, chronic illness, or liver disease. In some people, low IGF-1 is part of broader pituitary dysfunction, especially if other pituitary hormones are also abnormal. If your symptoms fit and your clinician is concerned, the next step is usually not “more IGF-1,” but targeted evaluation, which may include repeat testing and specialized stimulation tests for growth hormone.
Optimal (in-range) IGF-1 levels
An in-range IGF-1 generally suggests your average growth hormone activity is appropriate for your age and sex. If you still have symptoms, it does not mean “nothing is wrong,” but it makes a GH/IGF-driven explanation less likely and points toward other common contributors such as sleep quality, thyroid status, iron deficiency, inflammation, medication effects, or training load. Many people use an in-range result as a baseline for future comparison if their health status changes.
High IGF-1 levels
A high IGF-1 result raises the possibility of growth hormone excess, particularly if it is clearly above the reference range and you have compatible clinical features. However, interpretation still depends on context, because lab variation, physiologic states, and certain medications can shift IGF-1. When IGF-1 is persistently elevated, clinicians often confirm with additional testing (commonly an oral glucose suppression test for GH) and may evaluate the pituitary.
Factors that influence IGF-1
IGF-1 is affected by age, puberty status, pregnancy, and overall nutritional status, and it can drop during acute illness or significant caloric restriction. Liver function matters because the liver is a major source of circulating IGF-1, and kidney disease can also alter hormone handling. Medications and hormones can shift IGF-1 as well, including prescribed growth hormone, estrogen therapy (route and dose can matter), and some diabetes treatments. Because of these influences, repeating the test under stable conditions is often the most useful way to confirm a borderline result.
What’s included
- Igf 1, Lc/Ms
- Z Score (Female)
- Z Score (Male)
Frequently Asked Questions
Do I need to fast for an IGF-1 (LC/MS) blood test?
Fasting is not always required for IGF-1, but your ordering instructions may depend on whether IGF-1 is bundled with other labs (like glucose or lipids). If you are only testing IGF-1, many people schedule a morning draw under typical conditions and keep diet and training consistent beforehand for better comparability.
What is the difference between IGF-1 LC/MS and an IGF-1 immunoassay?
Both aim to measure IGF-1, but they use different measurement techniques. LC/MS is an instrument-based method that can improve analytical specificity and reduce certain interferences. Your clinician will still interpret the result using the lab’s reference range, and you should try to trend results using the same method and lab when possible.
Why does the IGF-1 reference range change with age?
IGF-1 naturally peaks during childhood and puberty and then declines over adulthood. Because of that, labs provide age- (and usually sex-) adjusted reference intervals. A value that is normal for a younger adult may be above range for an older adult, so the age-adjusted range is essential for interpretation.
If my IGF-1 is high, does that mean I have acromegaly?
Not by itself. A persistently high IGF-1 can be a screening clue for growth hormone excess, but diagnosis typically requires confirmatory testing and clinical evaluation. If your result is elevated, it is reasonable to discuss repeat testing and next-step evaluation with your clinician rather than assuming a diagnosis.
If my IGF-1 is low, does that prove growth hormone deficiency?
No. Low IGF-1 can occur with undernutrition, recent weight loss, acute or chronic illness, liver disease, and other conditions. When growth hormone deficiency is a concern, clinicians often use IGF-1 as a starting point and then decide whether specialized stimulation testing is appropriate.
How often should I retest IGF-1?
Retesting depends on why you tested in the first place. If you are confirming a borderline result, many clinicians repeat after several weeks under stable conditions. If you are monitoring a treatment or a major change in weight, training, or medications, a common approach is to recheck after about 8–12 weeks, since IGF-1 reflects longer-term signaling rather than hour-to-hour changes.
Can exercise or dieting change IGF-1?
Yes. Significant calorie restriction, rapid weight loss, and heavy training loads (especially with inadequate recovery) can lower IGF-1 in some people. On the other hand, improved nutrition and recovery can raise IGF-1 toward your personal baseline. For the cleanest trend, try to test during a relatively typical week for you.