Everything You Need to Know About Growth Hormone Therapy

Human growth hormone is an essential protein produced by your body. It helps kids grow, and it has several other functions throughout life. For example, it helps control blood glucose (sugar) and fat levels, maintain muscle and bone strength, and control fat distribution.

Growth hormone deficiency is a rare health condition. It occurs when the body doesn't make enough growth hormone. Growth hormone injections are a common treatment. Here, we'll discuss growth hormone therapy in depth - its history, how it works, and whether it's safe.

Note: Human growth hormone is often abbreviated as GH or hGH. It's also called somatotropin, or simply growth hormone. In this article, we'll refer to it as growth hormone.

What is growth hormone therapy?

Growth hormone therapy refers to a group of injectable medications that encourage growth in people who need it. These medications act like human growth hormone. They help your body boost levels of other hormones involved in growth. But these medications are lab made. So they're often referred to as synthetic, or recombinant, growth hormone. They can be administered at home with proper training.

Most growth hormone products simulate the natural form of growth hormone, called somatotropin. Examples include:

• Omnitrope

• Genotropin

• Humatrope

• Norditropin FlexPro

• Saizen

• Serostim

• Zomacton

• Zorbtive

These medications are usually administered daily or every other day. But they're not interchangeable. Each product may contain different amounts of somatropin and have different dosing instructions.

Other growth hormone medications are made using modified forms of somatotropin. These products tend to last longer in the body and are injected once weekly. Examples include Skytrofa (lonapegsomatropin), Sogroya (somapacitan-beco), and Ngenla (somatrogon).

What do growth hormone medications treat?

Not all growth hormone medications are FDA approved for the same conditions. FDA-approved uses in children include:

• Inadequate growth due to a growth hormone deficiency or unknown causes

• Children born small for gestational age

• Rare inherited disorders such as Turner syndrome, Noonan syndrome, and Prader-Willi syndrome

In adults, FDA-approved uses of growth hormone medications include:

• Growth hormone deficiencies

• HIV-associated weight and muscle loss (this is an approved use of Serostim)

• Short-bowel syndrome (this is an approved use of Zorbtive)

How was growth hormone therapy invented?

Growth hormone was first identified in the 1950s. Scientists were investigating why some people developed acromegaly. Researchers determined that too much growth hormone causes acromegaly. This led to the use of growth hormone to treat conditions of low growth.

First, they isolated growth hormone from pituitary glands (where growth hormone is made) in animals. But that didn't work. So they started using growth hormone from the pituitary glands of human donors who had died.

In 1985, researchers found that some adults who had received growth hormone injections as children developed a rare brain disease calledCreutzfeldt-Jakob disease (CJD). This was thought to result from receiving growth hormone that was contaminated with an abnormal form of a protein, called prion. Prions can cause other proteins in the body to fold abnormally. This can cause CJD.

The use of growth hormone from human donors stopped immediately. That same year, the FDA approved the first synthetic growth hormone product. It simulated the natural growth hormone. Since then, only synthetic, lab-made growth hormone has been used in humans. There's no risk of CJD with the growth hormone medications used today.

Some cases of Alzheimer's disease have been linked to growth hormone from humans. Researchers suspect donors carried beta-amyloid proteins, which cause Alzheimer's. Today's synthetic growth hormone medications do not carry this risk.

How does growth hormone therapy work?

Growth hormone therapy increases the amount of growth hormone in your body. This growth hormone attaches to growth hormone receptors (binding sites) in cells throughout the body. It causes the liver to release another protein, called insulin-like growth factor-1 (IGF-1). This has the following effects:

• Increases height (in some children, up to 4 inches in the first year of treatment)

• Stimulates growth of bone, cartilage, and collagen

• Increase muscle mass

• Reduces body fat

• Lowers fat levels in the body

• Helps control blood glucose

What are the risks of growth hormone therapy?

Growth hormone therapy is considered safe when used correctly. For adults and children with growth hormone deficiency, the benefits of growth hormone injections usually outweigh the risks.

Mild side effects from growth hormone therapy may include:

• Injection-site reactions, such as redness or itching

• Headache

• Fatigue

• Joint and muscle pain or stiffness

• Upper respiratory infections

• Tissue thinning or skin thickening near injection sites

• Swelling of the hands or feet

• Gas

More serious growth hormone side effects can also occur, but they're less common. Examples include:

• High blood pressure in the brain, leading to visual changes and headaches

• Carpal tunnel syndrome in adults

• Hypothyroidism (decreased thyroid hormone levels)

• Hypoadrenalism (decreased cortisol levels)

• Hip joint problems or worsening scoliosis in children

• Increased risk of Type 2 diabetes

• Loss of fat tissue in the body (lipoatrophy)

• Pancreatitis

• Severe swelling from fluid buildup in the body

Allergic reactions may also occur. If you experience side effects from growth hormone treatment that feel severe, seek emergency care.

Can growth hormone therapy cause cancer?

Higher levels of IGF-1 may increase cancer risk. So cancer has been considered a possible long-term concern with growth hormone therapy. But most research on this topic has been reassuring. A 2022 review of 24 studies, and close to 255,000 people, found no link between growth hormone treatment and cancer risk or death.

But researchers did find an increased risk of a new cancer diagnosis in participants who had cancer in the past. If you have had cancer before starting growth hormone therapy, tell your prescriber. You may need to avoid growth hormone treatment, or they may monitor you more closely if you receive it.

Can growth hormone slow the aging process?

Medical experts don't recommend human growth hormone for antiaging purposes. This is because it hasn't been found to slow the aging process - despite claims you might see.

It's understandable why there's interest in growth hormone as an antiaging treatment. Human growth hormone levels naturally peak at puberty and decline as you age. But boosting growth hormone levels above normal doesn't have clear benefits. What's more, research shows older adults may have a higher risk of harmful side effects. These can include fluid retention and joint problems.

Can growth hormone improve athletic performance?

Growth hormone injections haven't been found to definitively improve athletic performance in healthy adults. Studies have tested whether growth hormone has performance-enhancing benefits in young adults. But growth hormone didn't increase muscle strength or exercise ability. Some studies found that growth hormone therapy might even make exercise more difficult for some people.

For adults diagnosed with a growth hormone deficiency, treatment may improve athletic performance. This is because low growth hormone levels can decrease muscle mass. But research is less clear on whether treating a growth hormone deficiency improves strength and energy.

What are the potential harms of inappropriate use of growth hormone therapy?

Taking growth hormone therapy for unapproved uses puts you at risk for the side effects noted above. And you won't get much benefit. There might be other long-term risks when growth hormone is used inappropriately. This may include an increased risk of diabetes, fluid retention, and high blood pressure.

It's also worth considering this: More might not be better. Experts warn that taking growth hormone when you don't need it may lead to serious health problems.