Written by &you Labs Team
Updated September 19, 2026
Insulin-like growth factor 1, or IGF-1, is a hormone your liver makes. It answers a signal from growth hormone, sent by a small gland in your brain. An IGF-1 test tells you more than just how much you are growing. It also reflects your nutrition, your metabolic health, and how your body is aging.
The IGF-1 story is not simple. Both very low and very high levels carry risk. This guide walks you through what your number means and what moves it.
IGF-1 reflects growth hormone activity, nutrition, and your overall metabolic state. It naturally falls as you age. A healthy level sits in the middle to upper part of your age-adjusted range, not at the very top. For long-term health, the goal is moderate, not maximum.
Your liver makes IGF-1 after it gets a signal from growth hormone. Growth hormone comes from your pituitary gland, a small gland at the base of your brain. Think of growth hormone as a boss giving an order. IGF-1 is the worker who carries it out.
IGF-1 helps with:
What IGF-1 supports |
|---|
Muscle growth and repair |
Bone health |
How your body handles blood sugar |
Growth of your organs |
Growth hormone itself swings up and down through the day. IGF-1 stays much steadier. This is why doctors test IGF-1 instead of growth hormone directly.
Your healthy IGF-1 range depends heavily on your age. A result of 180 ng/mL means something very different for a 25-year-old than for a 70-year-old.
Age | Typical range (ng/mL) |
|---|---|
20s | 116 to 358 |
30s | 100 to 303 |
40s | 87 to 252 |
50s | 75 to 212 |
60s | 65 to 179 |
70 and up | 55 to 158 |
Always read your result against the range for your own age group.
Low IGF-1 | |
|---|---|
Common causes | Growth hormone deficiency, severe calorie restriction, long-term illness, severe liver disease, a pituitary gland problem |
What it can cause | Less muscle and strength, slow wound healing, more body fat, fatigue, low mood |
Next step | See a doctor to find the cause. Treatment depends on what is found |
High IGF-1 | |
|---|---|
Common causes | Acromegaly, a rare condition where a pituitary gland tumor makes too much growth hormone; growth hormone use; rarely, other tumors |
What it can cause | Tissue overgrowth, sleep apnea, joint pain, metabolic problems, higher cancer risk |
Next step | See a hormone doctor for imaging and further tests |
Most adults fall somewhere in their normal range. Where you sit within that range still matters.
The sweet spot is moderate, not at the bottom and not at the top of your range.
Researchers do not fully agree on this question yet.
The case for lower IGF-1:
The case for adequate IGF-1:
What this means for you: aim for the middle of your age range. Avoid two extremes. Do not restrict calories severely. Do not chase a high IGF-1 through extra protein, growth hormone, or other IGF-boosting products.
What raises it | What lowers it |
|---|---|
A high-protein diet | Getting older, which is a natural drop |
Resistance training, like weight lifting | Eating far too little |
Growth hormone treatment, which is rarely the right choice | A plant-forward diet with less protein and dairy |
Some medications | Long-term illness |
Pregnancy | Not enough sleep, or too much endurance exercise without rest |
Growth hormone deficiency |
IGF-1 testing is not for everyone. Doctors usually order it in specific situations, listed below.
Reason to test | What it looks like |
|---|---|
Signs of growth hormone deficiency | Ongoing fatigue and changes in body shape |
Signs of acromegaly | Growing hands, feet, or jaw, plus sleep apnea |
Growth hormone treatment | You need monitoring while on treatment |
Longevity tracking | You want a full longevity panel |
Growth concerns in a child | An unusual growth pattern |
Fertility workup | You are being checked for certain fertility issues |
IGF-1 is not part of every standard blood panel. Check the full list of what a &you Labs panel tests to see what is included.
Getting enough protein, about 1.2 to 1.6 grams per kilogram of body weight if you are active, supports a healthy IGF-1 level. A plant-forward diet tends to lower IGF-1 a bit. Eating far too little lowers it a lot.
Weight training raises IGF-1 and boosts growth hormone signals. Too much endurance exercise, without enough rest, can lower it instead.
Your body releases most of its growth hormone during deep sleep. Skimping on sleep lowers both growth hormone and IGF-1.
Extra fat around your belly affects IGF-1 too. This mostly happens through its effect on insulin and on inflammation.
Some studies link a higher IGF-1 to a higher risk of certain cancers, including breast, prostate, and colon cancer. The link is real, but it is modest. It is also not always a direct cause.
In practice, this means healthy adults should not try to push IGF-1 above the normal range through supplements or growth hormone. If you want your own IGF-1 and hormone picture, book your &you Labs panel to get a doctor's written read on your results.
Not usually. IGF-1 is most useful when you have a specific question, or as part of a full longevity panel. Most adults do not need it tested every year.
For most healthy adults, no. Growth hormone treatment carries real risks. These include insulin resistance, swelling, and joint pain. Some studies also link it to a higher cancer risk. It is meant for confirmed growth hormone deficiency, not for slowing aging.
A little, yes. Getting enough protein supports a healthy IGF-1 level. Eating a lot more protein than you need raises it only slightly further. Enough is the right target, not excess.
Long-term calorie cutting lowers IGF-1. A shorter eating window, say 10 to 16 hours a day, has only a small effect. A severe, ongoing calorie deficit lowers IGF-1 much more.
Often, yes. If diet, stress, or poor sleep caused it, eating enough, sleeping well, and exercising usually bring it back up. If a medical condition like growth hormone deficiency caused it, you may need treatment from a doctor.
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.
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