Compound record · Growth hormone axis

Somatropin

Also Recombinant human growth hormone · rhGH · hGH · HGH · Genotropin · Norditropin · Humatrope · Omnitrope · Saizen · Zomacton · Nutropin · Serostim

Recombinant human growth hormone

Growth hormone axisEvidence · StrongApproved medicine (for specific indications)WADA · Prohibited at all times

Prescription growth hormone: proven for deficiency, weak and risky for enhancement

Check my fit Compare

Record reviewed 1 September 2026 · 6 references

Class: Recombinant human growth hormone
Route: Daily subcutaneous injection (weekly long-acting forms exist)
Licensed for: GH deficiency and specific growth disorders (UK, US, EU, AU, CA)
Healthy adults: +2.1 kg lean, −2.1 kg fat, no strength gain (n = 220)
Legal note: WADA-prohibited; US federal offence to supply for anti-ageing or sport

01 Overview

What Somatropin is

Summary

Somatropin is recombinant human growth hormone, identical to the 191-amino-acid hormone made by the pituitary. It is authorised in every major jurisdiction as a prescription-only replacement for growth-hormone deficiency in children and adults and for a small number of specific growth disorders. In healthy adults, randomised trials show only small changes in body composition, no gain in strength or performance and a clear excess of adverse effects; in the US, supplying it for anti-ageing or athletic purposes is a federal offence.

Mechanism

Binds GH receptors on liver, muscle, bone and fat cells, stimulating IGF-1 production and directly promoting fat breakdown, protein synthesis and sodium and water retention. Injected GH produces a sustained, non-pulsatile exposure that suppresses the pituitary's own GH release through somatostatin and IGF-1 feedback, and it antagonises insulin action, raising blood glucose.

Routes studiedSubcutaneous injection

Anti-dopingProhibited at all times

02 Evidence by goal

What has been shown, for which goal

Grades follow one scale across the site. Strong overall means: multiple large randomised controlled trials or regulatory approval for this use.

Muscle & recovery
Limited
In healthy older adults (18 randomised trials, 220 GH-treated participants), about 27 weeks of GH increased lean mass by 2.1 kg without improving strength; in young athletes (27 studies, 303 treated), lean mass rose 2.1 kg — largely as extracellular water — with no improvement in strength or exercise capacity.
Fat loss / body composition
Limited
Fat mass fell by 2.1 kg on average in trials in healthy older adults while weight did not change; in adults with confirmed GH deficiency, replacement reduces visceral fat as a licensed benefit.
Athletic performance
Limited
The 2010 Sydney trial of 96 recreational athletes (2 mg daily for eight weeks) improved sprint capacity by 3.9% (8.3% with testosterone) but not endurance, strength or power, and the gain faded within six weeks; GH is prohibited at all times by WADA.
Longevity
Insufficient
Randomised trials in healthy older adults show no improvement in strength, bone density, lipids or function — only more oedema, joint pain, carpal tunnel syndrome and glucose problems. The Endocrine Society concludes GH cannot be recommended as an anti-ageing therapy, and higher IGF-1 levels have been linked to certain cancers in observational studies.

03 Regulatory status

Where it is authorised, and for what

Status is recorded per jurisdiction from regulator sources and reviewed by hand. It is never inferred from another region's decision.

United Kingdom

Authorised

Authorised (MHRA) for GH deficiency and specific growth disorders; prescription-only.

Multiple brands (Genotropin, Humatrope, Norditropin, Omnitrope, Saizen, Zomacton, NutropinAq) are licensed for GH deficiency in children and adults, Turner syndrome, chronic kidney disease growth failure, Prader–Willi syndrome, children born small for gestational age and SHOX deficiency. NICE TA64 (adults) and TA188 (children) set the criteria for NHS use. Prescribing for anti-ageing or performance is outside the licence.

StatusAuthorised

Status last reviewed1 September 2026

SourceOur maintained database — never inferred

04 Dosing research

What the evidence says about exposure

Published human studies and the doses, routes and durations they used — reported as research information, not a recommendation.

Research information — not a recommendation. These are the exposures used in published human studies, reported so you can see what has been tested. They are not dosing instructions and do not apply to any individual.

Study 01

Systematic review — GH in the healthy elderly

Liu H et al., Ann Intern Med 2007;146:104–115 · Source

Systematic review of randomised trials2007

Design: 31 articles describing 18 randomised controlled trial populations
Population: Community-dwelling adults with a mean age of 69 (mean BMI 28) without GH deficiency
Participants: n = 220
Duration: Mean 27 weeks (SD 16)
Route: Subcutaneous injection

Doses studied: Mean initial dose 14 µg/kg/day (SD 7), roughly 1 mg/day for an 80 kg adult
Outcome at this exposure: Fat mass −2.1 kg and lean mass +2.1 kg versus controls; weight unchanged. No consistent improvement in strength, bone density, lipids (after adjustment) or other clinical outcomes.
Adverse events observed: Significantly more soft-tissue oedema, arthralgia, carpal tunnel syndrome and gynaecomastia; a non-significant trend to more impaired fasting glucose and new diabetes. Women had more oedema than men.

Study 02

Systematic review — GH and athletic performance

Liu H et al., Ann Intern Med 2008;148:747–758 · Source

Systematic review of randomised trials2008

Design: 44 articles describing 27 study samples
Population: Young (mean age 27), lean, physically fit adults
Participants: n = 303
Duration: Mean 20 days (SD 18) for multi-dose studies; only three studies exceeded 30 days
Route: Subcutaneous injection

Doses studied: Mean 36 µg/kg/day (SD 21), roughly 2.5–3 mg/day for an 80 kg adult
Outcome at this exposure: Lean body mass +2.1 kg versus controls, but strength and exercise capacity did not improve; exercise lactate levels were higher in two of three studies measuring them.
Adverse events observed: Soft-tissue oedema and fatigue were more frequent in GH recipients.

Study 03

GH with or without testosterone in recreational athletes

Meinhardt U et al., Ann Intern Med 2010;152:568–577 · Source

Randomised trial2010

Design: Randomised, double-blind, placebo-controlled; 8 weeks of treatment then 6-week washout
Population: Recreationally trained athletes aged about 28 (63 men, 33 women)
Participants: n = 96
Duration: 8 weeks
Route: Subcutaneous injection

Doses studied: 2 mg once daily (men also randomised to testosterone 250 mg weekly intramuscularly or placebo)
Outcome at this exposure: GH reduced fat mass and increased lean body mass mainly through extracellular water; sprint capacity rose 3.9% overall and 8.3% with added testosterone, with no change in endurance (VO2max), strength (dead lift) or power (jump height). The sprint gain was no longer present six weeks after stopping.
Adverse events observed: Swelling and joint pain were more common with GH; no serious adverse events were reported in the 8-week study.

For comparison, licensed adult GH-deficiency replacement uses much lower, individualised doses: the Endocrine Society guideline (Molitch et al., JCEM 2011) suggests starting at 0.2–0.3 mg/day for adults aged 30–60 (0.1–0.2 mg/day over 60; 0.4–0.5 mg/day under 30), increasing by 0.1–0.2 mg every one to two months to keep IGF-1 within the age-adjusted reference range. The 2–6 mg/day regimens used for enhancement are several times higher and are where oedema, arthralgia and glucose intolerance become common.

05 Safety

Adverse effects and contraindications

Common effects seen in trials or reports, serious effects that warrant urgent review, and conditions under which use is not appropriate or needs assessment.

Common adverse effects

Peripheral oedema and fluid retention
Joint pain (arthralgia) and stiffness
Muscle pain
Tingling or numbness (paraesthesia) and carpal tunnel syndrome
Headache
Raised blood glucose and insulin resistance
Injection-site reactions and lipoatrophy
Fatigue (reported in athlete trials)
Breast tissue growth in men (gynaecomastia) at higher doses

Serious adverse effects

New-onset type 2 diabetes or glucose intolerance
Benign intracranial hypertension with headache, vomiting and visual disturbance
Worsening of proliferative diabetic retinopathy
Possible growth of existing tumours and second neoplasms in childhood cancer survivors
Increased mortality when given during acute critical illness
Sudden death in Prader–Willi syndrome with severe obesity or respiratory impairment
Unmasking of central hypothyroidism or adrenal insufficiency
Pancreatitis (rare)
Acromegaly-like changes — enlargement of jaw, hands and feet, cardiomyopathy — with prolonged supraphysiological dosing

Contraindications

CancerDo not use
Contraindicated with any active malignancy; anti-tumour therapy must be complete before treatment. Childhood cancer survivors have a higher rate of second neoplasms on GH, and previous cancer needs oncology review.
Acromegaly or pituitary tumourDo not use
Adding GH in acromegaly or with an active pituitary tumour is contraindicated.
Diabetic retinopathy (eye disease)Do not use
Contraindicated in active proliferative or severe non-proliferative diabetic retinopathy.
DiabetesCaution
GH causes insulin resistance and can unmask or worsen diabetes; glucose-lowering medicines often need adjustment and glucose must be monitored.
Raised intracranial pressureCaution
Benign intracranial hypertension (headache, visual disturbance, papilloedema) has been reported, usually early in treatment; previous raised intracranial pressure requires specialist assessment.
Sleep apnoeaCaution
GH can worsen upper-airway obstruction; deaths have occurred in people with Prader–Willi syndrome and severe obesity or respiratory impairment, which is a label contraindication.
Thyroid diseaseCaution
GH increases conversion of T4 to T3 and can unmask central hypothyroidism; thyroid function should be checked before and during treatment.
Hormonal disorderCaution
In hypopituitarism, GH increases cortisol clearance and can unmask adrenal insufficiency; glucocorticoid replacement may need adjustment.
Cardiovascular diseaseCaution
Fluid retention can worsen heart failure, and GH is contraindicated in acute critical illness (after open-heart or abdominal surgery, multiple trauma or acute respiratory failure) because of increased mortality.
High blood pressureCaution
Sodium and water retention can raise blood pressure, particularly at higher doses.

Do not use = should not be used · Caution = needs assessment

06 Interactions

Medicine classes that need review

Grouped by how seriously the combination should be taken. Class labels match the medicines questionnaire in the assessment.

Major
Moderate
Minor

Major

Combination should be reviewed by a prescriber before use.

Corticosteroid
Prednisolone, dexamethasone, hydrocortisone
Glucocorticoids blunt GH's effects, and GH increases cortisol clearance — people on replacement therapy may develop adrenal insufficiency without dose adjustment.
Insulin
Lantus, NovoRapid, Humalog, Tresiba
GH antagonises insulin; doses usually need adjusting and glucose monitoring is essential.
Growth hormone
Somatropin
Duplicate therapy — including long-acting weekly GH products (somatrogon, somapacitan, lonapegsomatropin).

Moderate

Monitoring or dose review is usually advised.

Sulfonylurea
Gliclazide, glimepiride, glipizide
Glucose control may deteriorate; dose review and monitoring advised.
Other glucose-lowering medicine
Metformin, SGLT2 inhibitors, DPP-4 inhibitors
Glucose-lowering effect may be partly offset; monitoring advised.
Hormone replacement therapy
Oestrogen, progesterone
Oral oestrogens blunt IGF-1 generation so women on oral (but not transdermal) oestrogen typically need substantially higher GH doses.
Oral contraceptive
Combined pill, progestogen-only pill
Oral oestrogen-containing contraceptives reduce the IGF-1 response to GH, altering dose requirements.
Thyroid hormone
Levothyroxine, liothyronine
GH alters thyroid hormone metabolism and can unmask hypothyroidism; levothyroxine doses may need adjustment.

Minor

Generally compatible; awareness is sufficient.

Testosterone / anabolic hormone
Testosterone gel or injection
Androgens amplify IGF-1 and body-composition responses to GH (as in the Meinhardt trial); combined use outside a licence multiplies adverse-effect risk.
Anti-epileptic
Lamotrigine, levetiracetam, valproate
GH can change cytochrome P450 clearance of anticonvulsants; monitoring advised.
Narrow-therapeutic-index medicine
Lithium, digoxin, ciclosporin
Clearance of ciclosporin and other CYP450-metabolised narrow-margin medicines may change.

07 Pregnancy & breastfeeding

Status in pregnancy

Not recommended

Not recommended in pregnancy: placental GH replaces pituitary GH after about 20 weeks, and labels advise stopping if pregnancy occurs. Breastfeeding data are lacking, although GH is unlikely to be absorbed by the infant.

08 Monitoring

What is usually monitored

Parameters that trials and product information track. A clinician decides what applies to an individual.

01IGF-1 kept within the age-adjusted reference range, rechecked after every dose change
02Fasting glucose and HbA1c at baseline and regularly
03Thyroid function before starting and during treatment
04Cortisol or adrenal reserve in anyone with pituitary disease
05Blood pressure, swelling, joint symptoms and hand tingling
06Eye examination if headaches or visual symptoms develop
07Age-appropriate cancer screening; lipid profile and bone density in confirmed deficiency

09 Combinations

What is known about combining it

Notes on pairing with other compounds in the directory: whether the combination has been studied in people, and where mechanisms overlap.

Tesamorelin
No human studies
Overlap · Duplicate GH-axis stimulation; injected GH suppresses the pituitary response tesamorelin relies on.
No rationale or data for combining; IGF-1 and glucose effects would be additive.
Sermorelin
No human studies
Overlap · Duplicate GH-axis stimulation; exogenous GH suppresses the response to GHRH analogues.
No rationale or data for combining.
CJC-1295
No human studies
Overlap · Duplicate GH-axis stimulation with days-long additive IGF-1 exposure.
No data; CJC-1295 is an unlicensed research chemical.
Ipamorelin
No human studies
Overlap · Duplicate GH-axis stimulation; exogenous GH suppresses secretagogue responses.
No data; ipamorelin is an unlicensed research chemical.
IGF-1 LR3
No human studies
Overlap · Additive IGF-1 exposure and compounded hypoglycaemia risk.
No human data; combines a licensed medicine with an untested laboratory reagent that acts on the same pathway.
Semaglutide
No human studies
Overlap · Opposing effects on glucose (GH raises it, GLP-1 lowers it) and both are used for body-fat goals.
No human studies of the combination; not covered by either licence.
BPC-157
No human studies
Marketed together as 'recovery' stacks; no human data for the combination and BPC-157 lacks human efficacy data.
TB-500
No human studies
No human data on the combination; TB-500 itself has no human efficacy data.

Discuss any proposed combination with a qualified healthcare professional.

10 Source considerations

Supply, quality and legitimacy

How the compound reaches people in practice, and what that means for product quality.

01Prescription-only medicine in every major jurisdiction, requiring a confirmed diagnosis of GH deficiency or another licensed indication.
02In the US, distributing GH for anti-ageing or athletic purposes is a federal crime (21 U.S.C. §333(e)); clinics offering 'HGH therapy' without a qualifying diagnosis are operating unlawfully.
03Counterfeit and diverted GH is common on the illicit market — vials may contain less GH, none at all, or other hormones; regulators and anti-doping agencies have documented this repeatedly.
04GH is a temperature-sensitive protein that needs cold-chain storage; 'HGH' oral sprays, pills and 'releaser' supplements do not contain growth hormone.

11 Questions for your clinician

Take these to your appointment

Specific to this compound. The personal assessment adds questions drawn from your own history and medicines.

01Has GH deficiency actually been confirmed with stimulation testing, or is this based on a single low IGF-1 result?
02If I do have deficiency, what starting dose and IGF-1 target will we use, and how often will it be checked?
03How will my diabetes, thyroid, steroid or oestrogen medicines be adjusted?
04Do I have any cancer history, diabetic eye disease or sleep apnoea that changes the decision?
05If the goal is body composition or performance, what does the evidence say I can realistically expect compared with the risks?
06Is the product from a licensed pharmacy with an intact cold chain?

The personal assessment tailors this list to your responses.

12 Alternatives

Compounds with stronger evidence or firmer regulatory footing

Listed for overlapping goals. Whether any is appropriate depends on your history — the assessment maps that for you.

13 References

Sources behind this record

Regulator documents and peer-reviewed publications used to derive every grade and statement above.

The Peptide Checkup provides educational information and a structured summary of published research and regulatory status. It is not medical advice, does not diagnose or treat any condition, and does not replace a consultation with a qualified healthcare professional.

Personal assessment

Check Somatropin against your history

Seven minutes of structured questions about your goal, history and medicines, mapped against this record by a deterministic, clinician-reviewable rules engine. The report tells you when not to buy.

Start the assessment Compare with another

What Somatropin is

Summary

Mechanism

What has been shown, for which goal

Muscle & recovery

Fat loss / body composition

Athletic performance

Longevity