I remember a mom coming into the clinic, her brow furrowed with worry. “Doctor,” she said, her voice a little shaky, “my son just isn’t growing like his friends. He’s always been on the smaller side, but now it feels… different.” It’s a common concern, and sometimes, it leads us to talk about something called Human Growth Hormone, or HGH. It’s a fascinating and vital part of how our bodies work, especially for kids, but for adults too.
So, What Exactly is Human Growth Hormone (HGH)?
Alright, let’s break it down. Human Growth Hormone, also known by its more scientific name somatotropin, is a natural hormone your body makes. Think of hormones as tiny messengers, carrying instructions through your blood to different parts of your body, telling them what to do and when.
The main production house for HGH is a tiny, pea-sized gland at the base of your brain called the pituitary gland. It’s a real powerhouse, making lots of different hormones. Specifically, the front part of your pituitary, the anterior lobe, is responsible for HGH.
Now, the pituitary doesn’t just decide to release HGH on its own. It gets its orders from the hypothalamus, a part of your brain just above it that controls things like blood pressure and body temperature. The hypothalamus sends out two key signals:
- Growth Hormone-Releasing Hormone (GHRH): This is the “go” signal, telling the pituitary to release HGH.
- Somatostatin: This is the “stop” signal, telling the pituitary to hold back.
It’s a delicate balance. For children, HGH is crucial for growth – helping them get taller. This happens until the growth plates (you might hear them called epiphyses) at the ends of their bones fuse, usually after puberty. Once that happens, HGH won’t make you taller, but your body absolutely still needs it. It helps maintain your body structure, keeps your metabolism ticking along, and even plays a role in keeping your blood sugar levels steady.
Sometimes, we doctors use a synthetic version of HGH to treat certain conditions. But this is something that should only be used under a doctor’s prescription and care.
What Gets Human Growth Hormone Going?
Your pituitary gland doesn’t just flood your system with HGH all at once. It releases it in short bursts, or pulses, throughout the day and night. As I mentioned, this release is mainly orchestrated by GHRH (go!) and somatostatin (stop!) from the hypothalamus.
But other things can nudge HGH levels too. For instance, Insulin-like Growth Factor 1 (IGF-1), a hormone mostly made in your liver that works closely with HGH, actually tells the pituitary to ease up on HGH production. It’s like a feedback loop: HGH triggers IGF-1, and then IGF-1 helps regulate HGH. Other hormones like thyroxine (from your thyroid), glucocorticoids (like cortisol), and ghrelin (the “hunger hormone”) can also encourage HGH release.
In a healthy person, things that can stimulate HGH release include:
- Sleep (especially deep sleep)
- Stress (though chronic stress isn’t good for overall health)
- Exercise
- Low blood sugar (hypoglycemia)
- Certain amino acids (the building blocks of protein)
On the flip side, high blood sugar (hyperglycemia) tends to put the brakes on HGH release.
The Big Jobs of Human Growth Hormone
HGH has two main gigs in your body: making you grow (especially when you’re a kid) and influencing your metabolism (how your body uses food for energy).
HGH and Growth
This is the one most people know about. HGH signals almost every tissue and organ in your body to grow. It’s particularly famous for its effect on cartilage and bone. It tells special cells in cartilage (called chondrocytes) and bone-building cells (called osteoblasts) to multiply, which is how bones get longer and you get taller.
Once those growth plates close, that’s it for height. But HGH then switches to a maintenance role, helping keep your body structure sound for the rest of your life.
HGH and Metabolism
Your metabolism is all the chemical processes that turn food into energy. HGH plays a part here, mainly by boosting the production of IGF-1. IGF-1 is a bit like insulin (the hormone that lowers blood sugar) and can also help lower blood sugar.
Your body is usually very good at keeping blood sugar in a healthy range. Insulin is the main player in lowering high blood sugar. HGH, interestingly, tends to raise blood sugar levels if they get too low. However, if you have too much HGH, it can work against insulin, leading to high blood sugar. It’s all about balance, you see.
Can HGH Make You Taller?
Yes, for children whose growth plates haven’t fused, HGH is what drives their increase in height. But once those growth plates are closed, no amount of HGH will make you taller. After that, it’s all about maintaining your body’s structure and supporting your metabolism.
What are “Normal” Human Growth Hormone Levels?
This is a tricky one. Because HGH is released in pulses, a random blood test for HGH isn’t usually very helpful. The levels can swing quite a bit depending on the time of day, your age, and even your sex.
Generally, we see ranges like this (but remember, labs can differ!):
- Adult Males: 0.4 to 10 nanograms per milliliter (ng/mL)
- Adult Females: 1 to 14 ng/mL
- Children: 10 to 50 ng/mL
If we’re concerned about HGH levels, we usually do special tests called stimulation tests (to see if the body can produce HGH when prompted) or suppression tests (to see if it stops producing HGH when it should). An IGF-1 test is often more useful for a general idea, as its levels are more stable. Always discuss your specific lab results with your doctor.
When Human Growth Hormone Levels Aren’t Quite Right
Sometimes, the body makes too little or too much HGH.
Too Little HGH: Growth Hormone Deficiency
This is when your body doesn’t produce enough HGH. Often, it’s due to an issue with the pituitary gland itself, a condition we call hypopituitarism, where the gland underproduces one or more hormones.
In Adults:
When adults don’t have enough HGH, they might experience:
- A general feeling of not being well
- Increased body fat
- A higher risk of heart disease
- Weaker heart, muscles, and bones
This can sometimes happen due to a non-cancerous tumor on the pituitary (a pituitary adenoma) or damage to the pituitary or hypothalamus.
In Children (and their parents!):
If your child isn’t making enough HGH, it primarily shows up as poor growth. The most telling sign after about age three is growing less than 1.4 inches in height per year. You might also notice:
- Their face looks younger than their age
- Hair growth might be slow or sparse
- Puberty might be delayed
Sometimes, kids are born with this (it could be genetic, or the cause might be unknown, or due to an injury during development or birth). Other times, it can develop later if the pituitary or hypothalamus is damaged.
Too Much HGH: Acromegaly and Gigantism
When the body produces too much HGH, it leads to a rare condition.
In Adults (Acromegaly):
If HGH levels are too high after the growth plates have closed, adults develop acromegaly. They don’t get taller, but their bones can thicken. You might see:
- Enlarged or swollen hands and feet
- Changes in facial features (like a more prominent jaw or brow)
They can also have enlarged organs and are at higher risk for high blood pressure, Type 2 diabetes, and heart disease. The most common cause? A pituitary adenoma that’s overproducing HGH.
In Children (Gigantism):
If a child has too much HGH before their growth plates fuse, they can grow exceptionally tall. This is often called pediatric acromegaly or, more commonly, gigantism. Without treatment, children can reach heights of seven feet or more. They might also experience:
- General weakness
- Delayed puberty
- Headaches
Again, a pituitary adenoma is usually the culprit.
Checking Your Human Growth Hormone Levels
If you or your child have symptoms that make us think about HGH, we can run some tests.
As I said, a single HGH blood test isn’t the most reliable. Instead, we often use:
- Growth hormone stimulation tests: We give a substance that should make the pituitary release HGH, then measure the response.
- Growth hormone suppression tests: We give something (like glucose) that should lower HGH, then see if it does.
- IGF-1 blood test: This level is more stable throughout the day and often gives us a good indication of average HGH activity.
Using Human Growth Hormone as a Treatment
The FDA has approved synthetic HGH for specific medical conditions. It’s given by injection and is only available by prescription.
In children, HGH might be prescribed for:
- Growth hormone deficiency
- Conditions causing short stature, like chronic kidney disease, Turner syndrome, and Prader-Willi syndrome.
In adults, HGH can be used for:
- Growth hormone deficiency
- Muscle wasting due to HIV
- Short bowel syndrome
It’s so important to only use HGH if it’s prescribed by your doctor for a diagnosed condition.
What About Side Effects?
Like any medication, synthetic HGH can have side effects. These can include:
- Carpal tunnel syndrome
- Increased insulin resistance or even Type 2 diabetes
- Swelling in the arms and legs (edema)
- Joint and muscle pain
- Enlargement of breast tissue in males (gynecomastia)
- Potentially an increased risk of certain cancers (though more research is ongoing)
We’re still learning about all the long-term effects of HGH treatment, which is another reason why it’s so carefully controlled.
Take-Home Message: Key Things to Remember About Human Growth Hormone
It’s a lot to take in, I know! But here are the main points about Human Growth Hormone:
- Natural & Necessary: HGH is a hormone your pituitary gland makes, crucial for childhood growth and lifelong body maintenance and metabolism.
- Complex Control: Its release is managed by signals from your hypothalamus and influenced by other hormones and bodily states.
- Growth & More: While it promotes height in kids, in adults it supports body structure, metabolism, and blood sugar regulation.
- Imbalances Have Impact: Too little HGH can lead to growth issues in kids and health problems in adults. Too much can cause acromegaly in adults or gigantism in children.
- Testing is Specific: We use specialized tests, not just random blood draws, to assess HGH levels properly.
- Treatment is Prescribed: Synthetic HGH is a powerful medication for specific conditions and should only be used under a doctor’s supervision.
When to Chat With Your Doctor
If you’re worried about your child’s growth, or if you’re an adult experiencing symptoms like unexplained changes in your body, energy levels, or well-being that might make you think of HGH issues, please do reach out. And if you or your child are already receiving treatment for an HGH-related condition, regular check-ins are key to make sure everything is on track.
You’re not alone in figuring these things out. We’re here to help.