How to Convert IGF-1 ng/mL to nmol/L
IGF-1 (insulin-like growth factor 1, or somatomedin C) is reported in ng/mL (or µg/L) in the US and in nmol/L across much of the world. The conversion factor is 0.131, from IGF-1's molecular weight of about 7,649.
IGF-1 nmol/L = IGF-1 ng/mL × 0.131 IGF-1 ng/mL = IGF-1 nmol/L ÷ 0.131 µg/L and ng/mL are identical for IGF-1 — only nmol/L needs the factor.
IGF-1 ng/mL to nmol/L Chart
| ng/mL (µg/L) | nmol/L | Context |
|---|---|---|
| 70 ng/mL | 9.2 nmol/L | Lower adult range |
| 100 ng/mL | 13.1 nmol/L | Low-mid |
| 200 ng/mL | 26.2 nmol/L | Mid adult |
| 400 ng/mL | 52.4 nmol/L | Upper (younger adults) |
| 780 ng/mL | 102.2 nmol/L | Upper (17–24 y) |
| 1000 ng/mL | 131 nmol/L | High (acromegaly range) |
nmol/L to ng/mL Reverse Chart
| nmol/L | ng/mL |
|---|---|
| 13.1 nmol/L | 100 ng/mL |
| 26.2 nmol/L | 200 ng/mL |
| 52.4 nmol/L | 400 ng/mL |
| 102.2 nmol/L | 780 ng/mL |
IGF-1 Reference Ranges by Age
This is what a bare converter misses. IGF-1 is highest in adolescence and declines steadily with age, so the same number is read completely differently at 20 versus 60. Approximate adult ranges:
| Age | ng/mL | nmol/L |
|---|---|---|
| 17–24 years | 180 – 780 ng/mL | 23.6 – 102.2 nmol/L |
| 25–39 years | 114 – 400 ng/mL | 14.9 – 52.4 nmol/L |
| 40–54 years | 90 – 360 ng/mL | 11.8 – 47.2 nmol/L |
| 55+ years | 70 – 290 ng/mL | 9.2 – 38.0 nmol/L |
Children and adolescents (puberty) run higher still. Use the Age range check tab above to test a value against its age band.
IGF-1 in Acromegaly and Growth Hormone Testing
IGF-1 is produced in response to growth hormone (GH). Because GH is secreted in pulses and swings widely through the day, while IGF-1 stays stable, IGF-1 is the preferred screening test for acromegaly (GH excess) — a persistently high IGF-1 for age is the key finding, then confirmed with an oral glucose tolerance test. A low IGF-1 for age can point to GH deficiency, but is also lowered by malnutrition, liver disease and poorly controlled diabetes, so it is never read alone.
Worked Example
Suppose a 60-year-old has an IGF-1 of 320 ng/mL and you want nmol/L:
320 × 0.131 = 41.9 nmol/L 320 ng/mL is above the 55+ range (70–290) — potentially significant at that age, even though the same value would be normal for a 25-year-old. That is why age matters.
Frequently Asked Questions
How do you convert IGF-1 ng/mL to nmol/L?
Multiply ng/mL by 0.131. For example, 200 ng/mL is about 26.2 nmol/L.
Is µg/L the same as ng/mL?
Yes — identical (1:1) for IGF-1.
Why does age matter for IGF-1?
IGF-1 falls with age, so it must be compared to an age-matched range.
What does high IGF-1 mean?
A high IGF-1 for age is the main screening sign of acromegaly.
References
- UnitsLab — IGF-1 (somatomedin C) unit conversion (ng/mL ↔ nmol/L).
- IGF-1 factor 0.131 (MW ≈ 7,649); µg/L = ng/mL (1:1); age-specific reference ranges from standard endocrinology references.
Conclusion
Converting IGF-1 between ng/mL and nmol/L is a ×0.131 (and µg/L = ng/mL). But the number only means something next to age — use the age-range check above, and interpret it with growth-hormone testing and your clinician.