Human growth hormone
Somatropin
An injected, man-made growth hormone used for growth hormone deficiency and some specific conditions.
What is Somatropin?
Somatropin is a man-made version of human growth hormone, given as an injection for people whose bodies do not make enough of it. In children it helps growth and development, and in adults with deficiency it helps energy, body composition and wellbeing. It is given using an easy-to-use pen, usually as a daily injection under the skin in the evening. It is generally well tolerated and is prescribed and monitored by a specialist.
Education and reference only. This is a plain-language guide to Somatropin — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Somatropin is a laboratory-made copy of human growth hormone, the hormone the pituitary gland normally produces to support growth and the way the body handles energy. It is used when the body does not make enough growth hormone — in children this can slow growth, and in adults it can affect energy, muscle, fat distribution and wellbeing. It is also used in certain specific conditions affecting growth. It is given by injection under the skin using a pen device.
How it works
Somatropin replaces missing growth hormone, acting on tissues throughout the body and prompting the liver to release a growth factor that drives growth and repair. In children this supports normal growth in height; in adults it helps maintain muscle, healthy fat distribution, bone strength and a sense of wellbeing. Given as a regular injection under the skin, it mimics the body's own hormone, and treatment is adjusted by a specialist based on response and blood tests.
Company & origin
Originated / developed by: Several manufacturers.
A man-made form of human growth hormone, given by injection in the UK for growth hormone deficiency and certain other conditions.
Practical use
How to take Somatropin
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Give it by injection under the skin using the pen device, exactly as your specialist team shows you.
- It is usually injected once a day, often in the evening, to match the body's natural pattern.
- Rotate the injection site (such as the tummy or thigh) to look after the skin.
- Store it as instructed, which is often in the fridge, and do not freeze it.
- Attend your specialist reviews and blood tests, as the dose is adjusted to your response.
- Report swelling, persistent headaches, joint pains or vision changes to your team.
Weighing it up
Advantages & disadvantages of Somatropin
Advantages
- Replaces a hormone the body genuinely lacks, supporting growth in children and wellbeing in adults.
- Given by an easy-to-use pen that most people can manage at home.
- Generally well tolerated, with treatment carefully tailored by a specialist.
Disadvantages
- It must be given by regular injection rather than taken as a tablet.
- Can cause fluid retention with swelling, joint aches or carpal-tunnel-type symptoms.
- Needs specialist supervision, regular monitoring and careful storage.
Practical use
Good to know
Somatropin is a specialist treatment, started and monitored by an endocrinology team, and it is replacing a hormone the body lacks rather than boosting normal levels. It is given by a pen device under the skin, usually once a day in the evening to mimic the body's natural rhythm, and most people learn to do this easily at home. It is generally well tolerated; the most common effects relate to fluid retention, such as mild swelling or joint aches, which often settle. Because it affects how the body handles sugar, blood sugar may be checked, and the dose is fine-tuned over time. It should be stored as instructed, often in the fridge.
Who should not take it / use with caution
- It should not be used in people with active cancer.
- It is avoided in those who are critically ill after major surgery, trauma or breathing failure.
- It is used with caution, and only by specialists, in diabetes and certain other conditions.
Monitoring
- In children, regular checks of height and growth to guide the dose.
- Blood tests including growth factor levels, blood sugar and thyroid function.
- Watching for fluid retention, headaches or vision changes, with specialist review.
Side effects
- Fluid retention causing mild swelling, joint or muscle aches, especially early on.
- Headache, tingling or numbness in the hands (carpal-tunnel-type symptoms).
- Reactions at the injection site and, less commonly, effects on blood sugar.
Key interactions
- Can change how the body handles steroids, sometimes needing the steroid dose adjusted.
- May affect insulin or diabetes tablet requirements, as it can influence blood sugar.
- Thyroid and sex hormone treatments can interact with how growth hormone works.
Available as: Solution for injection under the skin, given by a pen device.
Answers
Somatropin: frequently asked questions
What is somatropin used for?
It is a man-made growth hormone used when the body does not make enough — helping growth in children and energy, muscle and wellbeing in adults with deficiency, plus some specific conditions.
How is it given?
It is given as an injection under the skin using a pen device, usually once a day in the evening, and most people learn to do this easily at home.
Does it hurt or is it hard to use?
The pen uses a very fine needle and most people manage well after training; rotating sites and following the technique you are shown helps.
Is it safe?
It is generally well tolerated under specialist care. Most side effects relate to fluid retention, such as mild swelling or joint aches, which often settle with review.
How should I store it?
Store it as instructed, which is usually in the fridge, and do not freeze it; follow the leaflet for how long it can be kept once in use.
The wider class
About Growth hormone
Somatropin belongs to the growth hormone class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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