IGF-1 Calculator (Adults 18+)
Use this tool to compare your Insulin-like Growth Factor 1 (IGF-1) lab value against age- and sex-adjusted reference intervals.
Educational tool only. Lab methods and ranges vary by assay and laboratory. Always interpret with your clinician.
What is IGF-1?
IGF-1 (Insulin-like Growth Factor 1) is a hormone influenced by growth hormone (GH), nutrition status, liver function, sleep quality, and overall metabolic health. Clinicians often order IGF-1 as a more stable marker of GH activity because GH itself pulses throughout the day.
An igf 1 calculator can help you quickly check whether a value is below, within, or above the expected range for your age and sex. That context is important because IGF-1 naturally changes over time and tends to decline with age.
How this IGF-1 calculator works
Step 1: Convert units (if needed)
Most labs report IGF-1 in ng/mL, while some report in nmol/L. This calculator converts nmol/L to ng/mL using:
- ng/mL = nmol/L × 7.64
Step 2: Match your age and sex
The tool uses adult age bands and sex-specific reference intervals to identify a likely normal range. It then compares your value with that interval.
Step 3: Estimate z-score and percentile
To add more context, the calculator estimates an IGF-1 z-score and percentile from the reference interval. This is an approximation:
- Mean is estimated as midpoint of the interval.
- Standard deviation is estimated from interval width.
- Percentile is derived from the estimated z-score.
This can be useful for trend tracking, but it is not a substitute for a laboratory-provided z-score or endocrine evaluation.
How to interpret your result
- Below range: may be seen with GH deficiency, undernutrition, chronic illness, poorly controlled diabetes, liver disease, or normal biological variation.
- Within range: often reassuring, but symptoms and trends still matter.
- Above range: can occur with puberty, GH therapy, recovery states, or possible GH excess (e.g., acromegaly workup context).
A single IGF-1 result should always be interpreted with your full clinical picture, medications, sleep, training load, and other bloodwork.
Factors that can influence IGF-1 levels
Physiology and lifestyle
- Age and pubertal status
- Protein and calorie intake
- Sleep quality and duration
- Energy deficit and overtraining
Health conditions and medications
- Liver disease or chronic inflammation
- Diabetes and insulin resistance
- Estrogen route (oral vs transdermal)
- Growth hormone therapy and related endocrine treatment
Best practices when using an IGF-1 calculator
- Use the same laboratory when possible for follow-up testing.
- Compare trends over time rather than reacting to one data point.
- Log training, sleep, and nutrition around test dates.
- Review out-of-range values with a qualified clinician.
FAQ
Is a low IGF-1 always bad?
Not always. Mildly low values can occur in temporary states like dieting or poor sleep. Persistent low results with symptoms may warrant further endocrine assessment.
Can a high IGF-1 mean cancer?
IGF-1 alone is not a cancer diagnosis. Elevated values should be interpreted in context and may lead to additional evaluation, especially if levels are persistently high.
Can I use this for children or teens?
No. Pediatric interpretation requires pubertal staging and pediatric-specific reference data. This calculator is designed for adults (18+).
Clinical disclaimer
This page is for educational use and self-tracking only. It does not diagnose, treat, or replace personalized medical advice. If you have symptoms such as fatigue, muscle loss, abnormal growth, headaches, sweating, glucose changes, or menstrual/testosterone issues, discuss your labs with a licensed healthcare professional.