Human growth hormone, rhGH; Genotropin, Humatrope, Norditropin, Omnitrope, Saizen, Zomacton, Serostim, Nutropin AQ
Common dose
0.2–1 mg (0.6–3 IU) daily (label); 2–4 IU (community)
Cycle
Continuous
Vial sizes
10, 24, 36 IU
Typical draw
20 units10 IU with 1 mL, 2 IU
Recombinant human growth hormone: the same 191-amino-acid protein the pituitary gland makes. It raises IGF-1, builds lean tissue, breaks down fat and makes the body hold water and salt.
Evidence. FDA-approved since 1987 as daily injections for adults with growth hormone deficiency and several growth disorders in children, and as Serostim for HIV-associated wasting. Weekly long-acting versions (somapacitan, somatrogon, lonapegsomatropin) are different molecules. In healthy young adults, trials found more lean mass, much of it water, but no gain in strength.
What it’s used for
Approved uses first, then uses tested in people, then claims that rest on animal studies or user reports.
Growth hormone deficiency in adults
LabelApproved as replacement once testing confirms the deficiency. Across 54 trials in over 3,400 adults, body fat fell 2.6 kg and lean mass rose 1.4 kg vs placebo, with more swelling.
HIV-associated wasting
LabelSerostim is approved alongside HIV medicines. In a 12-week trial of 178 adults, weight rose 1.6 kg and lean mass 3.1 kg more than on placebo, and treadmill work output rose 13%.
Short bowel syndrome
LabelZorbtive was approved in 2003 for 4 weeks with a special diet but has no current US listing. In 41 adults, GH plus glutamine cut weekly IV nutrition most: 7.7 vs 3.8 liters.
Growth failure and short stature in children
LabelApproved, by brand, for GH deficiency, Turner, Noonan or Prader-Willi syndrome, SHOX deficiency, small size at birth or idiopathic short stature. Vial Guide doesn’t show children’s doses.
Muscle and athletic performance
TrialUnproven: across trials in 303 fit young adults, lean mass rose 2.1 kg, much of it water, but strength and exercise capacity didn’t improve. One 8-week trial found sprint capacity up 3.9%.
Anti-aging in healthy older adults
TrialNot recommended: in 18 trials, 220 people given GH for about 27 weeks lost 2.1 kg of fat and gained 2.1 kg of lean mass, but had more swelling, joint pain and carpal tunnel.
Fat loss in obesity
TrialUnproven for weight loss: in trials in adults with obesity, fat fell 0.9 kg and belly fat shrank, but weight didn’t drop, fasting blood sugar rose, and joint pain and swelling increased.
Reversing biological age
TrialUnproven: in an uncontrolled pilot, 9 men given GH with DHEA and metformin for a year had epigenetic age estimates about 1.5 years below baseline. A larger trial hasn’t reported.
Label: an approved use. Trial: tested in people, with the result.
Approved in the US since 1987 as Genotropin, Humatrope, Norditropin, Omnitrope and Zomacton for adults with growth hormone deficiency and several growth disorders in children, and as Serostim for HIV-associated wasting; Zorbtive, approved for short bowel syndrome, has no current listing. Distributing it for any other use is a federal crime, with up to 5 years in prison.
1987US FDA: Humatrope: first somatropin, for children with growth hormone deficiency
1996US FDA: Humatrope: first approval for adults with growth hormone deficiency
1996US FDA: Serostim: HIV-associated wasting, alongside HIV treatment
2003US FDA: Zorbtive: short bowel syndrome, with specialized nutrition
2006EU (EMA): Omnitrope: the first biosimilar medicine authorized in the EU
European Union
Prescription only. EMA authorized NutropinAq (2001) and Omnitrope (2006, the EU’s first biosimilar); other brands, such as Genotropin, are authorized nationally.
United Kingdom
Prescription-only medicine. Genotropin, Norditropin, Omnitrope, Saizen and Zomacton are licensed for adult GH deficiency and children’s growth disorders.
Canada
Prescription drug (Schedule D, a biologic). Genotropin, Norditropin, Omnitrope, Saizen and Serostim are marketed; Humatrope was cancelled in December 2025 and Nutropin AQ in January 2025.
Australia
Prescription only (Schedule 4), and possessing it without authority is illegal (Appendix D). Genotropin, Norditropin, NutropinAq, Omnitrope, Saizen and SciTropin A have current product information.
Sport (WADA 2026)
Banned in sportS2.2.3 growth hormone, its analogues and fragments, with lonapegsomatropin, somapacitan and somatrogon named. Banned at all times.
Sport status follows the WADA Prohibited List in force since January 1, 2026; athletes should confirm with their anti-doping organization. Checked October 5, 2026. Status outside the US checked October 7, 2026 against EMA, MHRA, Health Canada and TGA records. By country: EU, UK, Canada, Australia. Status of every compound.
How it works
Somatropin has the same 191-amino-acid sequence as the growth hormone made by the pituitary gland. It binds growth hormone receptors, docking sites on cells throughout the body, and the liver answers by making IGF-1, which carries much of the growth effect. It increases protein building, breaks down stored fat and makes the body hold sodium and water, and large doses impair blood sugar control.
LabelBased on the product label.
Not known
In healthy adults, much of the lean mass gained is water rather than muscle. The long-term effects of keeping IGF-1 above normal, on cancer, heart and diabetes risk, are unknown.
Protocol
Label
Genotropin, Humatrope, Norditropin, Omnitrope
Adults with growth hormone deficiency: start about 0.2 mg a day (range 0.15–0.3 mg, roughly 0.5–1 IU), raised every 1–2 months by 0.1–0.2 mg according to IGF-1 and side effects. EU labels say maintenance rarely exceeds 1 mg (3 IU) a day.
Label
Serostim
HIV-associated wasting: about 0.1 mg/kg once daily at bedtime, up to 6 mg (about 18 IU), with HIV treatment. Every other day is an option when side effects are a concern.
Community
Research vials: commonly 2 IU, up to about 4 IU, once a day under the skin, often at bedtime, in courses of 12 weeks or longer. 2–4 IU is about 0.7–1.3 mg, around or above the top of adult replacement doses.
Frequency
Once daily
Route
Subcutaneous injection
Timing
The deficiency labels don’t set a time of day; Serostim is given at bedtime, and research-vial users often inject at bedtime.
Cycle
Continuous for growth hormone deficiency, with the dose adjusted to IGF-1 (label). HIV-wasting trials ran 12 weeks, and Zorbtive’s course was 4 weeks. Research-vial courses commonly run 12 weeks or longer.
Week 15913172125
Continuous, shown over 26 weeks
Common protocols
The ways Somatropin (HGH) is most often run, each tagged with where it comes from.
Adult GH deficiency
Label
Dose
0.15–0.3 mg to start (about 0.5–1 IU)
How often
Once daily
How long
Long-term
Raised by 0.1–0.2 mg every 1–2 months to keep IGF-1 in the normal range. EU labels: maintenance rarely above 1 mg (3 IU). Older adults start lower; women on oral estrogen may need more.
HIV-associated wasting (Serostim)
Label
Dose
About 0.1 mg/kg, up to 6 mg
How often
Once daily at bedtime, or every other day
How long
12 weeks in the trials; no controlled data beyond 48 weeks
Taken with HIV medicines. Every-other-day dosing gave a similar gain in work output with fewer side effects.
Short bowel syndrome (Zorbtive)
Label
Dose
About 0.1 mg/kg, up to 8 mg
How often
Once daily
How long
4 weeks
Given with a specialized diet while on IV nutrition. Longer use wasn’t studied, and Zorbtive no longer has a current US listing.
Research vials
Community
Dose
2–4 IU
How often
Once daily, often at bedtime
How long
Often 12 weeks or longer
These amounts haven’t been tested for muscle, fat loss or aging. Vial contents are unverified, and black-market GH has held modified forms of the hormone.
Draw 20–40 units10 IU + 1 mL
Dosing by body weight
Label
0.004–0.016 mg/kg. Daily weight-based adult regimen (Norditropin 0.004–0.016 mg/kg; Humatrope 0.006–0.0125 mg/kg), not recommended with obesity. HIV wasting uses about 0.1 mg/kg (Serostim).
Taking it
Where it goes
Under the skin of the back of the upper arm, abdomen, buttock or thigh, rotating sites to avoid fat loss where injections are repeated (label).
If you miss a dose
The US labels give no missed-dose rule. The EU leaflet for Omnitrope says not to double up: take the next injection at the usual time the next day and note the missed dose for the doctor.
Swelling, joint pain and tingling tend to appear early and often ease with time or a lower dose. IGF-1 guides each dose change, every 1–2 months.
Label
6 months (adult GH deficiency)
Lean mass up 2.59 kg vs a 0.22 kg fall on placebo, and body fat down 3.27 kg vs a 0.56 kg rise (Humatrope).
Label
12 weeks (HIV wasting)
Weight 1.6 kg and lean mass 3.1 kg higher than on placebo, with treadmill work output up 13% (Serostim).
Label
8 weeks (healthy athletes)
Fat fell and lean mass rose, largely as extra body water. Sprint capacity rose 3.9%, but strength, power and endurance didn’t change, and the gain was gone 6 weeks after stopping.
Trial
Side effects and what to do
Swelling (label: leg and hand swelling 42% vs 8% on placebo in one 6-month adult trial; 17.5% vs 5.1% in another)
Usually early and dose-related. The labels advise a lower dose if it persists.
Joint and muscle pain (label: joint pain 17.3% vs 4.2%; 36% vs 11% in HIV wasting at 0.1 mg/kg daily)
Often eases with time or a dose reduction. Tell the prescriber if it persists.
Tingling, numbness and carpal tunnel syndrome (label: tingling 9.6% vs 1.9%; carpal tunnel in 2% of 3,031 adults in extension studies)
Most cases improved with a lower dose or a break; 9 of 61 needed surgery.
Higher blood sugar (label: type 2 diabetes 5% vs 0% in a 6-month adult trial; diabetes in 0.4% of 3,031 in extension studies)
The labels say to check glucose periodically, especially with obesity or a family history of diabetes.
Headache and raised pressure in the skull (label: headache 9.9% vs 7.7% on placebo)
A severe headache with vision changes or vomiting, usually in the first 8 weeks, needs an eye exam. It resolves after stopping or lowering the dose.
Stop and get medical help
Get medical help for a severe headache with vision changes or vomiting, severe belly pain that won’t go away, face or throat swelling or trouble breathing, or signs of very high blood sugar such as heavy thirst and frequent urination.
By the numbers
From the trials in the Norditropin label. Side effects count everything reported, whatever the cause, so the gap between the placebo and drug columns is what the drug adds.
Side effects vs placebo
Side effects over 6 months in adults whose growth hormone deficiency began in adulthood: those in at least 5% overall. Figures are the % of people.
Side effect
Placebon=52
Norditropinn=53
Swollen hands, legs or feet
8
42
Swelling from fluid
0
25
Joint pain
15
19
Swollen legs
4
15
Muscle pain
8
15
Infection (not viral)
8
13
Tingling skin
6
11
Bone pain
2
11
Headache
6
9
Bronchitis
0
9
Flu-like symptoms
4
8
High blood pressure
2
8
Gastroenteritis (stomach bug)
8
8
Other unclassified problems (not injuries)
6
8
Heavy sweating
2
8
Abnormal glucose tolerance (higher blood sugar)
2
6
Laryngitis (hoarse voice)
6
6
Type 2 diabetes
0
5
The label says fluid retention (swelling, joint and muscle pain, tingling, carpal tunnel) is common in adults, usually short-lived and dose-related.
In two placebo-controlled trials in 522 critically ill adults without GH deficiency, deaths were 42% on high doses (5.3 to 8 mg a day) vs 19% on placebo.
IGF-1 response: one 4 mg injection in healthy adults raised IGF-1 from 190 to 276 ng/mL after about 24 hours; it was back to 196 by 96 hours.
Results
Average change in body composition after 6 months in two placebo-controlled trials in adults with GH deficiency, counting everyone randomized.
Study 1: 31 adults, adult onset
Study 2: 49 adult men, onset in childhood
Measure
Placebon=16
Norditropinn=15
Placebon=13
Norditropinn=36
Lean body mass, kg
−0.63
+1.12
+0.70
+2.06
Body fat, % points
+1.92
−2.83
−1.78
−6.00
Measured by total body potassium; model-adjusted averages. Differences vs placebo: lean mass +1.74 (0.65 to 2.83) and +1.40 (0.39 to 2.41) kg; body fat −4.74 (−7.18 to −2.30) and −4.24 (−7.11 to −1.37) points (95% CI). Study 2 pooled three doses.
How the body handles it
Reaches the blood
Not yet known for injections under the skin, the label says
Peak level
About 4 to 5 hours after an injection under the skin in adults with GH deficiency; about 3.0 hours in healthy adults
Half-life
About 7 to 10 hours after an injection under the skin, because it absorbs slowly; about 21.1 minutes from a vein
Spread in the body
About 43.9 L (apparent volume of distribution, healthy adults)
Cleared by
Normal protein breakdown in the liver and kidneys; about 2.3 mL a minute per kg after an infusion
Source: Norditropin prescribing information (revised 07/2025). Trials of different drugs enrolled different people, so compare across drugs with care.
Can it cause …?
The side effects people ask about most, answered one by one. Each answer says where it comes from.
Tiredness
LabelFatigue: 5.8% vs 3.8% on placebo in adult trials (Genotropin). A review of trials in fit young adults also found fatigue more common on GH.
Headache
LabelHeadache: 9.9% vs 7.7% on placebo in adults. A severe headache with vision changes or vomiting can mean raised pressure in the skull, usually in the first 8 weeks.
Nausea or vomiting
LabelNausea: 9.1% vs 4.9% on placebo in HIV wasting at 0.1 mg/kg daily (Serostim). Nausea with vomiting can also signal raised pressure in the skull.
Diarrhea or constipation
LabelDiarrhea and constipation aren’t listed in the adult trials. Pancreatitis has been reported rarely, so the labels say persistent severe belly pain needs checking.
Dizziness
Not reportedNot a listed side effect in the adult trials, which included 1,145 adults with GH deficiency on Genotropin for up to 2 years.
Trouble sleeping
LabelTrouble sleeping isn’t listed in the adult trials. In Prader-Willi syndrome, the labels rule it out with sleep apnea or severe obesity after sudden deaths in children.
Hair loss
LabelNot listed in the adult trials. Hair loss was reported as drug-related in Genotropin’s trials in children with Prader-Willi syndrome.
Acne, rash or skin changes
LabelAcne: 6% vs 0% in adults (Humatrope). Fat loss at overused injection sites, rash or hives, and growth of existing moles have been reported; the labels say to watch moles.
Water retention or swelling
LabelThe most common effect: swelling of the legs or hands in 42% vs 8% on placebo in one 6-month adult trial (Norditropin). It is dose-related and often eases.
Joint or muscle pain
LabelJoint pain: 17.3% vs 4.2% on placebo in adults (Genotropin), and 36% vs 11% in HIV wasting. Carpal tunnel syndrome affected 2% of 3,031 adults in extension studies.
Anxiety, low mood or irritability
LabelNot listed in the adult trials. Aggressiveness was reported in children with Prader-Willi syndrome, and altered mood in children with short stature (Genotropin).
Low or high blood sugar
LabelIt raises blood sugar by reducing insulin sensitivity. Type 2 diabetes: 5% vs 0% on placebo in a 6-month adult trial; glucose-related reactions 22% vs 4% in HIV lipodystrophy trials.
Fast heartbeat or blood pressure changes
LabelHigh blood pressure: 8% vs 2% on placebo in a 6-month adult trial (Norditropin). Pooled adult trials found diastolic pressure fell slightly, by 1.8 mmHg.
More hunger
LabelMore hunger isn’t listed for adults. Increased appetite was among the common events in children with idiopathic short stature (Genotropin).
Liver strain
LabelAST, a liver enzyme, rose in 13% vs 0% on placebo among adults with childhood-onset GH deficiency (Humatrope). Use in liver disease hasn’t been studied.
Kidney problems
LabelKidney problems aren’t listed. It is cleared more slowly in chronic kidney failure, though no dose studies exist there, and it can raise calcium in the urine.
Cancer risk
LabelRuled out with active cancer. Childhood cancer survivors given head radiation had more second tumors, mostly meningiomas. In 15,809 treated adults, new cancers matched general-population rates.
Label: from the prescribing information. Not reported: studied in people and not reported. A side effect that hasn’t been reported can still happen, especially with long or high-dose use. Any of these across every compound: the side-effect finder.
Who should avoid it
What its label rules out or warns about, most important first.
Active cancer
LabelRuled out by the labels. Any past cancer should be inactive and fully treated, and treatment stopped if it returns; a pituitary or brain tumor should be ruled out first.
Acute critical illness
LabelRuled out after open-heart or abdominal surgery, multiple injuries or acute respiratory failure: in two intensive-care trials, deaths were 42% vs 19% on placebo at high doses.
Active or severe diabetic eye disease
LabelRuled out with active proliferative or severe non-proliferative diabetic retinopathy, damage to the retina’s blood vessels from diabetes.
Allergy to somatropin or its ingredients
LabelRuled out. Anaphylaxis and deep swelling of the face or throat have been reported, and some products contain m-cresol or come with a benzyl alcohol diluent.
Diabetes or high blood sugar
LabelNot ruled out, but it lowers insulin sensitivity and can unmask diabetes, so the labels advise checking glucose and adjusting diabetes drug doses.
Past brain or pituitary tumor, or head radiation
LabelThe labels advise routine checks for regrowth. Childhood cancer survivors given head radiation had more second tumors, mostly meningiomas, on somatropin.
Prader-Willi syndrome with severe obesity or apnea
LabelRuled out: sudden deaths were reported in children with Prader-Willi syndrome who were severely obese or had sleep apnea or airway blockage.
Interactions
Only interactions stated on a product label or measured in a human study are listed.
Glucocorticoid replacement (such as cortisone acetate or prednisone)
LabelSomatropin blocks the enzyme (11βHSD-1) that activates these drugs and can lower cortisol, so people treated for adrenal insufficiency may need higher maintenance or stress doses.
Drugs cleared by liver CYP450 enzymes (such as corticosteroids, sex steroids, seizure drugs and cyclosporine)
LabelSomatropin sped the clearance of a test drug, so it may change these drugs’ levels. The labels advise careful monitoring; no formal interaction studies exist.
Oral estrogen (birth control pills or menopausal hormone therapy)
LabelWomen taking estrogen by mouth may need a larger somatropin dose to reach the target IGF-1.
Insulin and other diabetes drugs
LabelDoses may need adjusting when somatropin is started, because it reduces insulin sensitivity.
HIV medicines (antiretrovirals)
LabelSomatropin boosted HIV replication in lab tests, so the Serostim label says to stay on antiretroviral therapy throughout; viral load didn’t rise in its trials.
Label: a product label rules it out, warns about it or lists the interaction. This isn’t a complete list: a pharmacist or doctor can check a specific medicine or condition. Every documented interaction, by medicine: drug interactions.
Special situations
What the label and studies say about pregnancy, breastfeeding, kidney and liver problems, age and surgery.
Pregnancy
LabelHuman data are too limited to judge the risk. Rat and rabbit studies at about 19–24 times human exposure showed no harm to offspring.
Breastfeeding
LabelUnknown whether it passes into milk. Limited data show it doesn’t raise growth hormone levels in milk, and no effects on breastfed infants have been reported.
Kidney problems
LabelNot studied in kidney impairment. The Serostim label notes slower clearance in chronic kidney failure but gives no dose guidance.
Liver problems
LabelNot studied in liver impairment, and the labels give no dose guidance. The liver is one of the main places growth hormone is broken down.
Older adults
LabelNot evaluated in people 65 and over. Older adults may be more sensitive to side effects, so the labels advise a lower starting dose and smaller increases.
Children and teens
LabelApproved, by brand, for growth failure from GH deficiency, Turner, Noonan or Prader-Willi syndrome, SHOX deficiency, small size at birth or idiopathic short stature; not for growth once growth plates close.
Surgery and anesthesia
LabelRuled out in acute critical illness after open-heart or abdominal surgery or major trauma, after intensive-care trials found more deaths (42% vs 19%). Tell the surgical team about any growth hormone use.
IGF-1 (label: dose adjusted to keep it within the normal range for age and sex)
Fasting glucose or HbA1c
Thyroid tests and cortisol (label: GH can unmask low levels)
Eye exam for swelling of the optic nerve, before starting and if headaches or vision changes appear
Moles, and tumor regrowth in anyone with a past pituitary or brain tumor
Often paired with
Usually run on its own.
Human studies
5 key published human studies, with how many people took part. Animal studies aren’t listed here.
20123,400 people
Body fat fell 2.56 kg and lean mass rose 1.38 kg vs placebo; swelling was 6 times and joint stiffness 4 times as common, and bone density didn’t change.
Design
Systematic review and meta-analysis of 54 randomized placebo-controlled trials in adults with growth hormone deficiency
Dose
Replacement doses, varying by trial
Length
Varied by trial
Hazem et al., Eur J Endocrinol 2012, PMID 21865409
2008303 people
Lean mass rose 2.1 kg more than without GH, but strength and exercise capacity didn’t improve; swelling and fatigue were more common.
Design
Systematic review of randomized controlled trials in fit, healthy young adults (mean age 27; 27 study groups)
Dose
Mean 36 mcg/kg a day
Length
Mean 20 days
Liu et al., Ann Intern Med 2008, PMID 18347346
201096 people
Fat fell and lean mass rose, largely as body water; sprint capacity rose 3.9%, strength, power and endurance didn’t change, and the gain was gone 6 weeks after stopping.
Design
Randomized blinded placebo-controlled trial in recreational athletes; men were also randomized to testosterone
Dose
2 mg a day under the skin
Length
8 weeks, then a 6-week washout
Meinhardt et al., Ann Intern Med 2010, PMID 20439575
2007220 people
Fat fell 2.1 kg and lean mass rose 2.1 kg with no change in weight; swelling, joint pain, carpal tunnel syndrome and breast growth in men were more common.
Design
Systematic review of randomized controlled trials in healthy older adults (mean age 69; 18 study groups)
Dose
Mean starting dose 14 mcg/kg a day
Length
Mean 27 weeks
Liu et al., Ann Intern Med 2007, PMID 17227934
1996178 people
Weight rose 1.6 kg and lean mass 3.0 kg, with fat down 1.7 kg, while placebo values barely changed; treadmill work output also rose more.
Design
Randomized double-blind placebo-controlled trial in adults with HIV-associated wasting
Dose
0.1 mg/kg a day (average 6 mg)
Length
12 weeks
Schambelan et al., Ann Intern Med 1996, PMID 8967667
Registered trials that are still running, or that finished without published results, most important first. Checked on ClinicalTrials.gov, October 7, 2026.
Phase 3NCT04867317
Somatropin vs placebo for 6 months in 172 US veterans with mild traumatic brain injury and adult GH deficiency: quality of life
Recruiting since January 2025; completion expected September 2029
Phase 4NCT07691125
4 weeks of somatropin in 100 adults with short bowel syndrome on IV nutrition, open-label: change in IV nutrition volume
Recruiting since July 2024; completion expected June 2028
Phase 4NCT05681299
GH with and without liraglutide, in 3-week crossover periods, in 40 healthy and GH-deficient adults: the appetite signal AgRP and metabolism
Recruiting since May 2023; completion expected April 2028
Not applicableNCT07568574
Medically supervised performance-enhancing drugs, including hGH, for up to 25 weeks in 60 elite athletes: side effects over 5.5 years
Enrolling by invitation since March 2026; completion expected 2033
Phase 2NCT04375657
TRIIM-X: GH with DHEA and metformin vs DHEA and metformin in 85 adults aged 40–80: thymus regrowth and epigenetic age
Listed as recruiting; completion was expected December 2025, record not updated since May 2025
Adult approval rests on 6-month placebo-controlled trials and their open extensions; a meta-analysis pooled 54 trials in over 3,400 adults with GH deficiency, and a registry followed 15,809 for about 5 years. Trials in healthy adults were small and short, mostly days to weeks, and none tested the doses or multi-year courses reported in sport. Research vials aren’t a regulated product, so their content is unverified.
Mixing your vial
Vial
Water
Common dose
Draw
Strength
Action
10 IU
1 mL
2 IU
20 units (0.20 mL)
10 IU/mL
24 IU
2 mL
2 IU
16.7 units (0.17 mL)
12 IU/mL
36 IU
3 mL
2 IU
16.7 units (0.17 mL)
12 IU/mL
Research vials are labeled in IU (EU labels: 1 mg is about 3 IU). With 1 mL of bacteriostatic water a 10 IU vial holds 10 IU/mL, so 2 IU is 20 units on a U-100 syringe; 24 and 36 IU vials mixed with 2 and 3 mL hold 12 IU/mL. The labels say to run the water down the vial wall and swirl, never shake. Approved products are dosed in mg: Norditropin pens and Omnitrope cartridges hold ready-made solution, while Genotropin and Humatrope cartridges and Serostim vials are powders mixed with their own diluent.
Dose chart
Syringe units for common doses at different water volumes. Select a cell to open it in the calculator.
Dose
Water added
1 mL
2 mL
3 mL
0.5 IU
0.6 IU
1 IU
1.5 IU
2 IU
3 IU
4 IU
U-100 insulin syringe: 100 units is 1 mL. Draws over 100 units show in mL. Faded values are under 2 units, which is hard to measure. Check that your vial holds the larger volumes.
Datasheet
Half-life
about 2–4 hoursLabelAfter an injection under the skin: 2.3 hours (Zomacton), 3.0 (Genotropin, adults with GH deficiency), 3.8 (Humatrope) and about 4 (Serostim); Norditropin’s label gives 7–10 hours. Given into a vein it lasts about 20–25 minutes; slow absorption from the skin explains the difference.
Type
Protein, 191 amino acids
Molecular weight
22,124.8 g/mol
Formula
C990H1528N262O300S7
Sequence
FPTIPLSRLFDNAMLRAHRLHQLAFDTYQEFEEAYIPKEQKYSFLQNPQTSLCFSESIPTPSNREETQQKSNLELLRISLLLIQSWLEPVQFLRSVFANSLVYGASDSNVYDLLKDLEEGIQTLMGRLEDGSPRTGQIFKQTYSKFDTNSHNDDALLKNYGLLYCFRKDMDKVETFLRIVQCRSVEGSCGFDisulfide bonds Cys53–Cys165 and Cys182–Cys189
Storage before use
Approved pens and cartridges: fridge at 2–8 °C in the carton, away from light, never frozen; Serostim vials at 15–30 °C. Research powder: freezer or fridge, dry and dark (community practice).
After mixing or opening
Norditropin pens: 4 weeks in the fridge or 3 weeks at up to 25 °C after first use. Genotropin and Omnitrope cartridges: 28 days in the fridge. Mixed research vials: 2–8 °C, used within a few weeks (community practice).
Molecule: FDA GSRS (UNII NQX9KB6PCL): sequence, disulfide bonds and 22,124.8 Da; Genotropin label (191 amino acids, 22,124 daltons); formula calculated from the sequence with both disulfide bonds
No development code in common use; abbreviated rhGH or r-hGH. Somatrem was the earlier 192-amino-acid form
Brand names
Genotropin, Humatrope, Norditropin, Omnitrope, Saizen, Zomacton, Serostim, Nutropin AQ (NutropinAq in Europe) and SciTropin A (Australia); Zorbtive is no longer listed in the US
First described
Isolated from human pituitaries in 1956 (Li and Papkoff); first made by recombinant DNA in 1979 (Goeddel et al.).
Approved products are dosed in mg (EU labels: 1 mg is about 3 IU); research vials are labeled in IU. Lab analyses of black-market GH found a modified 192-amino-acid form and, in a counterfeit, more degraded protein than the original.
Cautions
Ruled out with active cancer. Childhood cancer survivors given head radiation had more second tumors, mostly meningiomas, on somatropin, and the labels say to watch moles for growth.
Raises blood sugar by reducing insulin sensitivity; new type 2 diabetes has been reported, and diabetes drug doses may need adjusting.
Swelling, joint and muscle pain, tingling and carpal tunnel syndrome are common, especially early and at higher doses.
Ruled out in acute critical illness: in two intensive-care trials, deaths were 42% vs 19% on placebo at 5.3–8 mg a day.
Raised pressure in the skull (headache, vision changes, vomiting), usually in the first 8 weeks. Rare pancreatitis, and low cortisol or thyroid levels can be unmasked.
Questions
What is somatropin (HGH)?
Recombinant human growth hormone: the same 191-amino-acid protein the pituitary gland makes. It raises IGF-1, builds lean tissue, breaks down fat and makes the body hold water and salt.
How does somatropin (HGH) work?
Somatropin has the same 191-amino-acid sequence as the growth hormone made by the pituitary gland. It binds growth hormone receptors, docking sites on cells throughout the body, and the liver answers by making IGF-1, which carries much of the growth effect. It increases protein building, breaks down stored fat and makes the body hold sodium and water, and large doses impair blood sugar control. In healthy adults, much of the lean mass gained is water rather than muscle. The long-term effects of keeping IGF-1 above normal, on cancer, heart and diabetes risk, are unknown.
Is somatropin (HGH) FDA-approved?
Approved in the US since 1987 as Genotropin, Humatrope, Norditropin, Omnitrope and Zomacton for adults with growth hormone deficiency and several growth disorders in children, and as Serostim for HIV-associated wasting; Zorbtive, approved for short bowel syndrome, has no current listing. Distributing it for any other use is a federal crime, with up to 5 years in prison.
What is the usual somatropin (HGH) dose?
From the label (Genotropin, Humatrope, Norditropin, Omnitrope): Adults with growth hormone deficiency: start about 0.2 mg a day (range 0.15–0.3 mg, roughly 0.5–1 IU), raised every 1–2 months by 0.1–0.2 mg according to IGF-1 and side effects. EU labels say maintenance rarely exceeds 1 mg (3 IU) a day. HIV-associated wasting: about 0.1 mg/kg once daily at bedtime, up to 6 mg (about 18 IU), with HIV treatment. Every other day is an option when side effects are a concern (Serostim). These are the amounts sources reference, not recommendations.
How much water do I mix somatropin (HGH) with?
There’s no single right amount, because the water only sets the strength. With 1 mL of bacteriostatic water in a 10 IU vial, the strength is 10 IU/mL, so 2 IU is 20 units on a U-100 insulin syringe. More water makes small doses easier to measure. The dose chart above shows other volumes.
Who should avoid somatropin (HGH)?
Active cancer: Ruled out by the labels. Any past cancer should be inactive and fully treated, and treatment stopped if it returns; a pituitary or brain tumor should be ruled out first. Acute critical illness: Ruled out after open-heart or abdominal surgery, multiple injuries or acute respiratory failure: in two intensive-care trials, deaths were 42% vs 19% on placebo at high doses. Active or severe diabetic eye disease: Ruled out with active proliferative or severe non-proliferative diabetic retinopathy, damage to the retina’s blood vessels from diabetes. The “Who should avoid it” section lists 4 more groups and 5 interactions.
What is the half-life of somatropin (HGH)?
About 2–4 hours, according to the prescribing information. After an injection under the skin: 2.3 hours (Zomacton), 3.0 (Genotropin, adults with GH deficiency), 3.8 (Humatrope) and about 4 (Serostim); Norditropin’s label gives 7–10 hours. Given into a vein it lasts about 20–25 minutes; slow absorption from the skin explains the difference.
How should somatropin (HGH) be stored?
Approved pens and cartridges: fridge at 2–8 °C in the carton, away from light, never frozen; Serostim vials at 15–30 °C. Research powder: freezer or fridge, dry and dark (community practice). Norditropin pens: 4 weeks in the fridge or 3 weeks at up to 25 °C after first use. Genotropin and Omnitrope cartridges: 28 days in the fridge. Mixed research vials: 2–8 °C, used within a few weeks (community practice).
Is somatropin (HGH) banned in sport?
Yes. S2.2.3 growth hormone, its analogues and fragments, with lonapegsomatropin, somapacitan and somatrogon named. Banned at all times.
Has somatropin (HGH) been studied in people?
Yes. The human studies section lists 5 published studies. The largest, from 2012, included 3,400 people. Body fat fell 2.56 kg and lean mass rose 1.38 kg vs placebo; swelling was 6 times and joint stiffness 4 times as common, and bone density didn’t change.
How long has somatropin (HGH) been studied in people?
Trial KIMS registry: 15,809 adults on Genotropin, followed for an average of 5.3 years. The placebo-controlled trials lasted 6 months, with open extensions to 18 months or more.
Does somatropin (HGH) come in other forms, like a pill or nasal spray?
Label Approved only as injections under the skin: daily somatropin, or weekly long-acting versions, which are different molecules. No nasal, oral or skin form of growth hormone is approved.
Can you drink alcohol while taking somatropin (HGH)?
Precaution The labels don’t address alcohol, and no study has tested the combination. Growth hormone can raise blood sugar, and heavy drinking also disturbs blood sugar control.
Can somatropin (HGH) be taken with semaglutide or tirzepatide?
Label No published study has combined them. The labels say diabetes drug doses may need adjusting when somatropin starts. Registered trials are testing GH with liraglutide, and a weekly GH with semaglutide.
What happens if you take too much somatropin (HGH)?
Label Per the labels, a short-term overdose can cause low and then high blood sugar and fluid retention; long-term overuse can cause acromegaly (enlarged hands, feet and face). Call Poison Help (1-800-222-1222), or emergency services for severe symptoms.
Omnitrope EU product information, sections 2 and 4.2 (EMA, 2026)
Maison et al., GH and cardiovascular risk factors in GH-deficient adults, meta-analysis (J Clin Endocrinol Metab 2004) PMID 15126541
Schambelan et al., GH in HIV-associated wasting (Ann Intern Med 1996) PMID 8967667
Byrne et al., GH, glutamine and diet in short bowel syndrome (Ann Surg 2005) PMID 16244538
Liu et al., growth hormone in the healthy elderly, systematic review (Ann Intern Med 2007) PMID 17227934
Mekala and Tritos, GH therapy in adults with obesity, meta-analysis (J Clin Endocrinol Metab 2009) PMID 18940879
Fahy et al., TRIIM pilot: epigenetic aging after GH, DHEA and metformin (Aging Cell 2019) PMID 31496122
Krug et al., new growth-promoting black market products, including a 192-amino-acid GH (Growth Horm IGF Res 2018) PMID 29864719
Jiang et al., mass spectrometry of innovator, counterfeit and follow-on recombinant GH (Biotechnol Prog 2009) PMID 19224592
Li and Papkoff, growth hormone from human and monkey pituitary glands (Science 1956) PMID 13390958
Goeddel et al., expression in E. coli of a DNA sequence coding for human GH (Nature 1979) PMID 386136
FDA Global Substance Registration System record (UNII NQX9KB6PCL) and WHO ATC index (H01AC01)
EMA medicines data for somatropin products (downloaded October 8, 2026)
UK summaries of product characteristics for Genotropin (PL 00057/0988), Norditropin, Omnitrope, Saizen and Zomacton (emc, checked October 8, 2026)
Health Canada Drug Product Database entries for somatropin products (checked October 8, 2026)
Australian Poisons Standard, October 2026 (somatropin in Schedule 4 and Appendix D), and TGA product information search (October 2026)
ClinicalTrials.gov registry entries for the trials listed (checked October 8, 2026)
Doses tagged Community come from public dosing guides and user reports, checked against at least two of them. Those sites aren’t named here because many of them sell peptides or earn commissions on them.