Insulin-Like Growth Factor (IGF): What You Should Know

Medically reviewed by Graham Rogers, MD on May 26, 2016Written by Ann Pietrangelo on May 26, 2016

What is insulin-like growth factor (IGF)?

IGF is a hormone that your body makes naturally. It used to be known as somatomedin. IGF, which comes mainly from the liver, acts a lot like insulin.

IGF helps to control growth hormone secretion in the pituitary gland. IGF works with growth hormones to promote growth and development of bone and tissue. These hormones also affect how your body metabolizes sugar, or glucose. IGF and insulin can work together to rapidly reduce the level of glucose in your blood.

What is the connection between diabetes and IGF?

If you have diabetes, your body doesn’t make enough insulin or can’t use it properly. You need insulin to process glucose for energy. Insulin helps to distribute glucose to cells throughout your body while reducing glucose in your blood.

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In a 2010 study, lower IGF levels were associated with diabetes. Those findings were for people under age 65 who didn’t have cardiovascular disease. The researchers adjusted for a variety of other factors, including serum cholesterol, lifestyle, and body mass index. Researchers couldn’t make the IGF-diabetes association in people over age 65.

Low levels of IGF may be linked to the increased secretion of growth hormones in people with type 1 diabetes. Growth hormone concentrations in people with diabetes are 2 to 3 times higher than in people who don’t have diabetes.

Abnormal levels of IGF and growth hormones may also play a role in the complications of diabetes.

A link appears to exist between obesity, type 2 diabetes, and cancer risk. Some studies indicate a connection between these diseases and higher levels of IGF, insulin resistance, and inflammatory markers.

What testing is available for IGF?

A simple blood test can determine how much IGF you have in your blood.

Doctors may also order this test when a child isn’t growing or developing as expected for their age.

In adults, this test is most likely to be performed to check for pituitary gland disorders or tumors. It is not routinely given to people with diabetes.

IGF is measured in nanograms per milliliter (ng/mL). The normal ranges are:

  • 182-780 ng/mL for people ages 16-24
  • 114-492 ng/mL for people ages 25-39
  • 90-360 ng/mL for people ages 40-54
  • 71-290 ng/mL for people 55 and up

If your test results show higher or lower levels than the normal range, there could be several explanations, including:

  • low thyroid hormone levels, or hypothyroidism
  • liver disease
  • diabetes that isn’t well-controlled

If your IGF levels aren’t within the normal range, it doesn’t necessarily mean there’s anything wrong. Your doctor will be able to offer an explanation based on a broader range of information.

High levels of IGF may increase your risk for colorectal, breast, and prostate cancer, though no recent studies have reviewed this connection. Insulin that people use to treat type 2 diabetes may also increase the risk of certain cancers.

Can you use IGF to treat diabetes?

Mecasermin (Increlex) is an artificial version of IGF. It’s a prescription medication doctors use to treat growth failure in children. One of the potential side effects of mecasermin is hypoglycemia. If you have hypoglycemia, that means you have low blood glucose.

Research shows that IGF is capable of suppressing type 1 diabetes in mice. In type 1 diabetes, the body’s immune system turns on itself, attacking beta cells in the pancreas that produce insulin. IGF may be able to defend against the body’s own attack.

Some studies have shown that treatment with IGF may help control diabetes. It hasn’t been developed for treatment of diabetes due to severe side effects, including:

  • swelling of the optic nerve
  • retinopathy
  • muscle pain
  • joint pain

While promising research exists, the relationship between IGF and diabetes is complicated. More research is necessary before doctors can use IGF to treat this complex disease.

What about IGF in supplements?

A variety of dietary supplements contain growth hormones, including IGF. Companies promote them for anti-aging, energy, and improving the immune system, among other claims.

The U.S. Anti-Doping Agency warns that products that say they contain IGF-1 may not. It might also be diluted or the product could contain other potentially harmful substances. People may also misuse or abuse IGF-1.

The side effects of IGF-1 may be similar to those of other growth hormones. These include overgrowth of body tissues, known as acromegaly, and damage to the joints, liver, and heart.

IGF-1 can cause your blood glucose levels to drop. If you have diabetes, or even if you don’t, it’s important to check with your doctor before taking supplements that contain any growth hormones.

What is the outlook?

Research suggests IGF may be connected to diabetes, but people don’t fully understand the connection. You may be able to treat your diabetes with IGF, but this is still experimental.

Talk to your doctor before taking IGF or before trying any other supplements, and don’t alter your treatment plan without speaking with your doctor. Diabetes is a complicated disease, and it can cause many complications if you don’t get treatment for it.

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