Insulin-Like Growth Factor 1 (IGF-1): What This Metabolic Marker Reveals
Written by &you Labs Team
Updated
IGF-1 is easy to measure, but tricky to read. It is the main, longer-lasting signal of your growth hormone activity. It drives muscle growth and tissue repair. Its link to aging is complex too. Both a very high and a very low result can point to a problem.
Quick answer
IGF-1 is a hormone made mostly by your liver, in response to growth hormone. It carries out many of growth hormone's effects on your tissues. Normal ranges change with age. They run high in youth, then drop over time. A very high result can point to acromegaly or a higher cancer risk. A very low result can point to a growth hormone shortage or aging. Both ends are worth a closer look. The healthy target sits in the middle of your age range, not at the very top.
Lab testing that's built around you
What IGF-1 does
Your pituitary gland releases growth hormone. That hormone tells your liver to make IGF-1. IGF-1 then carries out most of growth hormone's work in your body. It lasts longer in your blood than growth hormone itself, which makes it easier to test.
IGF-1 supports several things. Cell growth and repair. Muscle protein building. Bone strength and brain function. In some cases, it even lowers inflammation.
Normal ranges by age
IGF-1 peaks in the teenage years, then falls steadily with age.
Age | Typical range (ng/mL) |
|---|---|
20 to 30 | 116 to 340 |
30 to 40 | 100 to 280 |
40 to 50 | 100 to 250 |
50 to 60 | 100 to 220 |
60 to 70 | 90 to 200 |
70 and up | 80 to 180 |
Always compare your result to your own age group, not to a younger person's range.
When IGF-1 runs high
Cause | Notes |
|---|---|
Acromegaly | A pituitary tumor that makes too much growth hormone. Causes a clearly high result |
Pregnancy | A normal, expected rise |
Teen years | A normal, expected rise during growth |
Growth hormone use | From medicine, or from misuse |
Acromegaly can also cause a few other signs.
- Bigger hands, feet, or jaw.
- Headaches and joint pain.
- Heavy sweating and snoring.
- High blood sugar and high blood pressure.
It is rare, but serious. It needs a specialist. Doctors confirm it with a glucose test that checks growth hormone, plus a scan of the pituitary gland.
A higher IGF-1, even within the normal range, is linked to a higher risk of some cancers. This includes prostate, breast, and colon cancer. It is not a screening test on its own. It is one factor among many.
When IGF-1 runs low
Cause | Notes |
|---|---|
Growth hormone shortage | A pituitary problem |
Normal aging | A gradual, expected decline |
Not eating enough | From strict dieting or illness |
Long-term illness | Including liver disease |
Untreated low thyroid | Slows IGF-1 production |
Poorly controlled diabetes | Lowers IGF-1 |
A true shortage in adults can bring a few changes.
- Less muscle, and more body fat, especially around the belly.
- Low energy and mood changes.
- Weaker bones and heart changes.
Doctors confirm it with special stimulation tests and a pituitary scan. Treatment is growth hormone therapy, under a specialist's care.
The aging pattern
A slow drop in IGF-1 after your 30s is normal and expected. But a very low IGF-1 in an older adult is a different story. It is linked to muscle loss, weak bones, memory decline, and a shorter lifespan. On the other end, a very high IGF-1 in adults is linked to a higher cancer risk. Both ends of the range carry some risk. The middle of your age range is the real target, not the highest number possible.
IGF-1 and living longer
The full picture is complex. In many lab animals, less IGF-1 signaling tends to extend lifespan. People who live to 100 often have lower IGF-1 too. But in regular adults, a very low IGF-1 is linked to more frailty and a higher risk of death. The likely answer: aim for a moderate, age-appropriate level. Do not try to push it to either extreme.
What moves your IGF-1
Raises it | Lowers it |
|---|---|
Enough protein | Getting older |
Strength training | Strict calorie cutting |
Good, deep sleep | Not enough protein |
Enough daily calories | Poor sleep |
Healthy thyroid function | Long-term illness |
Healthy liver function | Low thyroid function |
How much you eat shapes IGF-1, and it shapes your hunger signals too. Leptin and ghrelin are the hunger hormones a blood test can reveal.
If you want IGF-1 checked with your other hormones, you can book a &you Labs panel.
When to test IGF-1
Testing makes sense in a few cases: signs of acromegaly, signs of a growth hormone shortage, or a family history of pituitary tumors. It also fits a full longevity panel. It can help with unexplained muscle loss in an older adult too. It is not needed for routine yearly screening in someone with no symptoms.
Reading your result
Pattern | What it suggests |
|---|---|
Mid-range for your age | A normal, healthy growth hormone system |
Low, with frailty in an older adult | Worth checking nutrition, sleep, and activity. May need a growth hormone workup |
Very high | Worth checking for acromegaly. Ask about a referral |
Low, during intentional calorie cutting | May be an expected part of that approach. Discuss with your doctor |
Very low in a young adult | Worth a full growth hormone workup |
IGF-1 and sports performance
Strength training and enough protein raise IGF-1 in a healthy, natural way. Taking growth hormone or IGF-1 as a performance drug is a different story. It carries real heart, metabolic, and cancer risks. It is also banned in most sports.
IGF-1 is available as an add-on to a full hormone panel. It fits people building a longevity-focused picture of their health. It also fits anyone working through unexplained muscle loss or fatigue.
Frequently asked questions
Should I take growth hormone to raise my IGF-1?
No, not without a confirmed shortage. Growth hormone therapy is for a diagnosed deficiency, not general anti-aging use. Unsupervised use carries real heart, diabetes, and cancer risks.
Will protein supplements raise my IGF-1?
Getting enough protein supports a normal IGF-1. Extra protein beyond what you need has little added effect in a healthy adult.
Why is my IGF-1 lower than it was 10 years ago?
This is normal, age-related decline. Compare your result to your current age range, not to your younger self.
Does intermittent fasting affect IGF-1?
Yes, it can modestly lower it. Many researchers see this as part of how fasting may support long-term health.
Is a high IGF-1 always a problem?
Not always. A high-normal result is often fine. A very high, or borderline-high, result in an adult is worth checking for acromegaly.
Lab testing that's built around you
Key takeaways
- IGF-1 reflects your growth hormone activity, and it stays steadier in your blood than growth hormone itself.
- Always compare your result to your own age range. IGF-1 naturally falls as you get older.
- A very high result can point to acromegaly or cancer risk. A very low result can point to shortage or aging.
- The healthy target is the middle of your age range, not the highest number possible.
- Sleep, protein, and strength training support a healthy IGF-1. Medicine-based changes need a specialist.
The &you Labs Team combines medical science with personal care. We help Filipinos understand their health markers with blood work analysis that is easy to follow, whole person support, and health expertise built for Filipino life.
This content is provided for educational purposes only and is not intended as medical advice. It should not replace professional medical consultation, diagnosis, or treatment. Please consult a qualified healthcare provider to discuss the risks and benefits of any treatment option.
