Peptides explained
Human growth hormone: how it works
Also known as: HGH / somatropin
Page updated · Sources and editorial approach
Growth hormone explained: pituitary signalling, IGF-1, authorised replacement treatment and the distinction from performance or anti-ageing claims.
Human growth hormone at a glance
What it does biologically
Growth hormone affects growth and the handling of protein, fat and carbohydrate. Some actions are mediated by IGF-1.
What the evidence shows
Authorised somatropin medicines have specific indications and specialist monitoring. Replacement in confirmed deficiency differs from enhancement in a healthy person.
What remains uncertain
A hormone's normal function does not establish that additional hormone is beneficial or appropriate without a diagnosed indication.
The basics
What is Human growth hormone?
Human growth hormone is a protein hormone made by the pituitary gland. Somatropin is recombinant human growth hormone used in specific prescription medicines.
Growth hormone is distinct from GHRH analogues such as tesamorelin and from IGF-1 analogues such as LR3. They act at different points in the endocrine system.
Biological action
How does Human growth hormone work?
Growth hormone binds its receptor and influences metabolism directly and through downstream IGF-1. The normal hormone participates in growth and tissue physiology.
Replacement treatment aims to address a diagnosed deficiency. A treatment result in that setting cannot be used as proof of a general performance or anti-ageing benefit.
Questions being investigated
What do studies examine?
Confirmed deficiency
Specialist assessment distinguishes deficiency from an isolated symptom or a single hormone measurement.
Growth and metabolism
Clinical endpoints depend on age, diagnosis and the particular medicine.
Product identity
Biological medicines require product-specific evidence and manufacturing controls.
Strength of evidence
How strong is the evidence?
Evidence is separated by level because a cell experiment, an animal model, a human trial and a regulatory decision answer different questions.
| Evidence type | What it tells us |
|---|---|
| Laboratory | Growth-hormone receptor signalling is established biology. |
| Animal | Experimental models do not establish appropriate enhancement in healthy people. |
| Human | Authorised products have clinical evidence for defined populations, including confirmed deficiency. |
| Regulatory | Somatropin is a prescription biological medicine, with product-specific indications. |
Important context
Risks, limitations and unanswered questions
- Excess exposure can cause harm rather than additional benefit.
- Glucose effects and fluid-related symptoms are among the clinical safety considerations.
- An authorised medicine and a separately supplied HGH-labelled sample are not automatically equivalent.
Reading the original evidence
A medicine assessment has a defined scope
The EMA assessment describes Omnitrope and its conditions of use. It is not a general endorsement of HGH-labelled materials or performance-enhancement claims. Read the product name and authorised indication before applying a medicine's evidence to a broader assertion.
Question to take to the source: Is the source about the same authorised product and clinical indication as the claim?
Check the original source ↗For personal accounts and research questionnaires, read user feedback and patient-reported outcomes.
Detailed catalogue research
HGH and somatropin research: growth hormone replacement evidence
Learn how clinical evidence for prescribed somatropin differs from claims about HGH, ageing and performance.
What is the difference between human growth hormone and somatropin?
Human growth hormone is a protein hormone made by the pituitary. Somatropin is recombinant human growth hormone used in defined prescription medicines. Growth hormone signalling can influence circulating IGF-1, but the two hormones act through different receptors. A product label containing the letters HGH is not enough to establish a pharmaceutical identity or equivalence.
How is evidence for growth hormone deficiency assessed?
Clinical evidence depends on the patient group. A child with a defined growth disorder and an adult with confirmed growth hormone deficiency have different indications and outcomes. The named product's prescribing information describes who was studied, who may be treated and what monitoring is required. Effects of replacement in a diagnosed deficiency cannot establish benefits for someone without that condition.
What should readers look for in HGH body-composition claims?
Check whether a study measured fat, lean mass, strength or daily function. Those measures are related but not equivalent. Clinical assessment must also consider risks such as fluid retention and effects on glucose regulation. Evidence from one authorised medicine does not identify the contents or quality of a separately labelled HGH product.
Sources for this research section
Questions answered
Human growth hormone FAQs
Is HGH the same as IGF-1?
No. GH can stimulate IGF-1 production, but they are different hormones.
Does medical replacement prove an anti-ageing benefit?
No. Diagnosed deficiency and enhancement in healthy adults are different clinical questions.
Check the sources
Sources and further reading
Follow the original study or official information to check the population, methods and full results. Reviews and sponsor updates are labelled below.
- EMA: Omnitrope assessment ↗Regulatory explanation of a specific somatropin medicine and its indications.
- Omnitrope official US label ↗Product-specific mechanism, indications and safety information.
- UK Genotropin prescribing information ↗Source for the detailed research section.
Educational information, prepared with AI assistance and not independently clinically reviewed. It is not personal medical advice or a treatment recommendation. Read the editorial policy or suggest a correction.