HGH

Dosing from the Literature

Published for muscle and growth hormone: the label's weight-based and IGF-1-guided doses for deficiency. Not published: an approved dose for anti-aging or bodybuilding.

Somatropin doses depend on the indication: the labels give children weight-based weekly doses, split over 6 or 7 days, and adjust adults' doses to clinical response and serum IGF-1 (Genotropin label). Doses are in milligrams; older literature uses international units, about 3 IU per mg (Serostim label).

What It Is

Human growth hormone (hGH, somatropin) is a 191-amino-acid single-chain polypeptide hormone produced by somatotroph cells of the anterior pituitary gland and released in pulsatile bursts under the combined control of hypothalamic (brain's hormonal control center) growth-hormone-releasing hormone (GHRH), ghrelin, and the inhibitory somatostatin. It is the master anabolic and body-composition hormone of vertebrate physiology — driving linear growth during childhood and adolescence, maintaining lean body mass and bone density during adulthood, and regulating lipid metabolism, glucose handling, and tissue repair across the lifespan.

Recombinant human GH (rhGH, somatropin) has been commercially available since 1985, when Genentech launched Protropin (methionyl-rhGH produced in E. coli) as a replacement for pituitary-extracted cadaveric GH following the recognition of Creutzfeldt-Jakob disease transmission in the cadaveric supply. Modern commercial rhGH is sequence-identical to endogenous 22 kilodalton human GH — 191 amino acids, two intrachain disulfide bonds, molecular weight 22,125 daltons. It is produced in E. coli (most brands) or in mouse-cell mammalian expression systems (Saizen), purified to pharmaceutical grade, and supplied as lyophilized powder or pre-formulated solution in multi-dose pen devices (Genotropin Pen, NordiPen, HumatroPen, Saizen easypod) or single-use vials.

Approved brands on the US market as of April 2026 include Genotropin (Pfizer), Norditropin (Novo Nordisk), Humatrope (Lilly), Omnitrope (Sandoz — the first US rhGH biosimilar approved in 2006), Saizen (EMD Serono), and Zomacton (Ferring). Long-acting / weekly rhGH formulations — Skytrofa (lonapegsomatropin; Ascendis) approved 2021 for pediatric GHD and Sogroya (somapacitan; Novo Nordisk) approved 2020 for adult GHD and 2023 for pediatric GHD — are bioengineered for sustained delivery rather than daily injection. The weekly products represent the most significant pharmaceutical change in the rhGH landscape in two decades.

FDA-approved indications for daily somatropin encompass pediatric GH deficiency (including idiopathic GHD, growth failure from chronic kidney disease, Turner syndrome, Prader-Willi syndrome, SHOX deficiency, idiopathic short stature, Noonan syndrome, and short-gestation SGA without catch-up growth), adult GH deficiency (confirmed by GH stimulation testing), AIDS-associated wasting, and short bowel syndrome (Zorbtive, higher-dose). Adult anti-aging and body-composition use is not an FDA-approved indication, and distributing GH for it is a federal crime under 21 USC §333(e) (the "Anabolic Steroid Control Act" GH provision), with or without a prescription (Liu et al., 2007).

Mechanism of Action

Somatropin binds to dimeric GH receptors (GHR) on the membranes of target cells, setting off signaling inside the cell (Norditropin label). Some of its effects are direct and others run through IGF-1, among them cartilage-cell growth, glucose output from the liver, protein synthesis and fat breakdown (Norditropin label).

• GH receptor homodimerization — GH engages two copies of the cell-surface GH receptor (GHR, a type I cytokine receptor) with 1:2 stoichiometry, inducing conformational rearrangement of pre-formed GHR homodimers and activating the constitutively-associated JAK2 tyrosine kinase (Brown et al., Nat Struct Mol Biol 2005; PMID 16116438).
• Gene transcription — Receptor signaling induces transcription and translation of GH-dependent proteins, including IGF-1, IGFBP-3 and the acid-labile subunit (ALS) (Norditropin label).
• Hepatic IGF-1 production — About 85% of circulating IGF-1 comes from the liver (Molitch et al., 2011). IGF-1, which may play a role in skeletal growth, is generally low in children with GH deficiency and tends to rise on treatment (Genotropin label).
• Direct lipolysis — Fat breakdown is primarily a direct effect of somatropin rather than one carried by IGF-1 (Omnitrope label); in people with GH deficiency it has mobilized fat, reduced body fat stores and raised plasma fatty acids (Genotropin label). Increased lipolysis is one of the most consistent responses to GH; in adults with GH deficiency the fall in body fat, preferentially visceral in some studies, appears within 6 months (Molitch et al., 2011).
• Protein synthesis / nitrogen retention — Somatropin increases cellular protein synthesis, and nitrogen retention, shown by lower urinary nitrogen and serum urea nitrogen, follows the start of treatment (Genotropin label).
• Counter-regulatory (insulin-antagonistic) — Somatropin stimulates glucose output from the liver (Norditropin label) and may decrease insulin sensitivity, particularly at higher doses; large doses may impair glucose tolerance (Genotropin label).
• Bone and cartilage — In children, somatropin stimulates skeletal growth through the growth plates of long bones (Genotropin label), including cartilage-cell differentiation and proliferation (Norditropin label). In adults with GH deficiency, the guideline counts skeletal integrity among its benefits (Molitch et al., 2011); in Genotropin's adult trials, bone mineral density fell over the first 6 months and was back at baseline by 12 (Genotropin label).

What the Research Shows

The rhGH evidence base spans four decades of controlled trials in GH-deficient populations plus a parallel literature on off-label anti-aging and body-composition use in GH-sufficient adults. Evidence quality diverges sharply between these two domains.

• Pediatric GH deficiency — registrational pediatric trials — rhGH at 0.16–0.3 mg/kg/week SubQ (the range across the Genotropin and Humatrope labels) produces durable height velocity acceleration and final adult height recovery in children with confirmed GHD. FDA approval basis dates to 1985 (Protropin) and has been expanded across brands. Safety profile in pediatric populations is well-characterized through the Kabi International Growth Study (KIGS) and National Cooperative Growth Study (NCGS) post-marketing registries.
• Adult GH deficiency (Molitch et al., J Clin Endocrinol Metab 2011; PMID 21602453) — Endocrine Society clinical practice guideline synthesizing two decades of adult GHD trial data. rhGH replacement in confirmed adult GHD (GH stimulation test failure in appropriate clinical context) normalizes body composition (visceral fat reduction, lean-mass gain), improves bone density, exercise capacity, lipid profile, and quality of life measures (QoL-AGHDA). Its suggested starting dose is 0.2–0.3 mg/day at ages 30–60 (0.1–0.2 mg/day over 60; 0.4–0.5 mg/day under 30), raised every 1–2 months toward an IGF-1 level in the age-adjusted reference range.
• Rudman NEJM 1990 (PMID 2355952) — Landmark six-month controlled study in 21 healthy men aged 61 to 81 with low IGF-1: 12 received growth hormone and 9 no treatment, with no placebo and no randomisation reported. rhGH 0.03 mg/kg SubQ 3×/week produced 8.8% increase in lean body mass, 14.4% decrease in fat mass, and 1.6% increase in lumbar spine bone density. The study that launched the anti-aging GH industry — and the study whose generalizability to healthy GH-sufficient adults has been debated ever since.
• Liu et al. systematic review (Ann Intern Med 2007; PMID 17227934) — 31 articles on 18 randomized trial populations of rhGH in healthy older adults (220 GH-treated participants). Meta-analytic body-composition benefit: lean mass +2.1 kg, fat mass −2.1 kg. No consistent benefit on muscle strength, bone density, or functional status. Substantially higher adverse event rates (soft tissue edema, arthralgia, carpal tunnel, gynecomastia, impaired glucose tolerance). The most cited independent appraisal of anti-aging GH.
• Weekly rhGH pediatric GHD (Thornton et al., J Clin Endocrinol Metab 2021) — heiGHt phase 3 trial of lonapegsomatropin (Skytrofa) demonstrated non-inferior height velocity versus daily somatropin in treatment-naive pediatric GHD; supported FDA approval in 2021.
• Weekly somapacitan adult GHD (Johannsson et al., J Clin Endocrinol Metab 2020; PMID 32022863) — REAL1 phase 3 trial in 301 treatment-naive adults with GHD: once-weekly somapacitan cut truncal fat percentage more than placebo at 34 weeks (difference −1.53 points); its comparison with daily somatropin was not designed as a confirmatory test, and improvements were maintained with both to 86 weeks. FDA approval 2020 (Sogroya).
• AIDS-associated wasting (Serostim) — rhGH 0.1 mg/kg/day (capped at 6 mg/day; Serostim label) approved in 1996 for AIDS-associated catabolic states; FDA approval based on lean-body-mass recovery in wasting patients. Modern antiretroviral therapy has substantially reduced the patient population for this indication.
• Short bowel syndrome (Zorbtive) — Higher-dose rhGH 0.1 mg/kg/day up to 8 mg/day for 4 weeks, approved 2003 for short bowel syndrome in patients receiving specialized nutritional support (Zorbtive label, 2003).
• KIGS pediatric safety (Wilton et al., J Pediatr 2010; PMID 20400105) — Long-term safety data from the Kabi/Pfizer International Growth Study paediatric registry: among 58,603 treated children with no cancer-predisposing condition, 32 new malignancies against 25.3 expected (16.4 per 100,000 patient-years; standardised incidence ratio 1.26, 95% CI 0.86–1.78).
• SAGhE long-term mortality, Belgium, the Netherlands and Sweden (Sävendahl et al., J Clin Endocrinol Metab 2012; PMID 22238393) — Preliminary registry report on 2,543 patients treated with rhGH in childhood for isolated GH deficiency, idiopathic short stature or small size for gestational age (46,556 person-years): of 21 deaths, 12 were accidents and 4 suicides, and none was from cancer or cardiovascular disease. Data from the French part of SAGhE, released earlier, had raised concerns about long-term safety.
• Cancer risk — epidemiologic IGF-1 — Elevated serum IGF-1 in the upper reference range is epidemiologically associated with increased risk of colorectal, prostate, and breast cancers (Pollak, Nat Rev Cancer 2012; PMID 22337149). Several epidemiological studies have not shown an increased cancer risk with GH treatment; the Endocrine Society guideline still lists active malignancy as a contraindication and titrates adult doses to an IGF-1 level within the age-adjusted reference range (Molitch et al., 2011).

Human Data

The following are representative pivotal, post-marketing, and systematic-review references across rhGH's four decades of clinical use.

• Rudman et al., NEJM 1990 (PMID 2355952) — Six-month controlled study, 12 men treated against 9 untreated; 8.8% lean-mass gain and 14.4% fat-mass reduction in the treated men. The foundational anti-aging reference.
• Molitch et al., JCEM 2011 (PMID 21602453) — Endocrine Society adult GHD clinical practice guideline; diagnosis, treatment, and monitoring framework.
• Liu et al., Ann Intern Med 2007 (PMID 17227934) — Systematic review of anti-aging rhGH; modest body-composition benefit without functional gains; increased adverse events.
• Johannsson et al., JCEM 2020 (PMID 32022863) — REAL1 phase 3 trial of weekly somapacitan for adult GHD.
• Thornton et al., JCEM 2021 — heiGHt phase 3 trial of weekly lonapegsomatropin in pediatric GHD.
• Wilton et al., J Pediatr 2010 (PMID 20400105) — KIGS long-term pediatric safety registry.
• Sävendahl et al., JCEM 2012 (PMID 22238393) — SAGhE preliminary mortality report from Belgium, the Netherlands and Sweden: no deaths from cancer or cardiovascular disease among 2,543 people treated with GH in childhood.
• Growth Hormone Research Society / Consensus Statements — Periodic international consensus on diagnosis and treatment of adult and childhood GHD; most recent updates via JCEM consensus papers.
• Kaplan et al., NEJM 1985 — Original approval-supporting Protropin pediatric GHD trial.
• Mauras et al., J Clin Endocrinol Metab 2000 (PMID 11061518) — Randomized trial of high-dose (0.7 mg/kg a week) versus standard GH (0.3 mg/kg a week) in 97 GH-deficient adolescents in puberty; the high dose increased near-final height.
• Grinspoon et al. AIDS wasting pivotal trials — Basis of Serostim 1996 FDA approval for AIDS-associated catabolism.
• Seguro et al. short bowel syndrome pivotal trial — Basis of Zorbtive 2003 FDA approval.

Reconstitution & Storage

Somatropin comes as a ready-made solution in pens or cartridges, or as a powder with its own diluent. Each product's label sets its own storage and in-use limits, summarized below.

• Reconstitution (lyophilized powders) — The labels describe aiming the diluent against the glass wall of the vial and swirling gently, not shaking (Serostim label), and say a solution that is cloudy or contains particles is not to be injected; a usable solution is clear and colorless (Genotropin label).
• Pen devices — The pens' instructions describe a flow check (Norditropin, Sogroya) or priming (Omnitrope) with each new pen or cartridge, not before every injection, then dialing the prescribed dose; the labels rotate injection sites to avoid lipoatrophy (Norditropin and Omnitrope labels).
• Injection sites — The labels list the back of the upper arm, abdomen, buttocks and thigh (Norditropin label); the Omnitrope instructions say not to inject near the navel or waistline (Omnitrope label). The site is rotated daily for daily somatropin (Genotropin label) and weekly for weekly Sogroya (Sogroya label).
• Needles — The pens' instructions list 29–31 gauge pen needles (Genotropin and Omnitrope labels) and a new needle for each injection (Norditropin and Sogroya labels).
• Travel — The Genotropin instructions describe carrying the pen in its case in an insulated bag, protected from heat and freezing, and putting it back in the refrigerator as soon as possible (Genotropin label). Time allowed out of the refrigerator differs by product: 30 minutes a day for a mixed Humatrope cartridge, up to 3 weeks at up to 25°C for an in-use Norditropin pen, up to 6 months at up to 30°C for unused Skytrofa cartridges (Humatrope, Norditropin and Skytrofa labels).
• Timing — The Omnitrope label gives the daily injection preferably in the evening and the Serostim label at bedtime; Sogroya's weekly dose can be given at any time of day (Omnitrope, Serostim and Sogroya labels).

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Side Effects & Risks

In adults with GH deficiency, the most common side effects, in 5–18% of patients, come from fluid retention: paresthesias, joint stiffness, peripheral edema, joint pain and muscle pain. Patients who are older, heavier or female are more prone to them, and most improve when the dose is lowered (Molitch et al., 2011).

• Soft tissue edema / fluid retention — In Genotropin's placebo-controlled trials in adults with GH deficiency, peripheral swelling was reported by 17.5% in the first six months against 5.1% on placebo, and peripheral edema by 10.8% against 2.6%; these events came early in treatment and tended to be transient or to respond to a lower dose (Genotropin label).
• Arthralgia and myalgia — Joint pain was reported by 17.3% of adults with GH deficiency in the first six months of Genotropin's trials against 4.2% on placebo, and by 6.9% at 6–12 months; muscle pain by 4.9% against 1.6%. The label counts both among the effects of fluid retention, usually transient and dose dependent (Genotropin label).
• Carpal tunnel syndrome — A nerve compression syndrome the labels count among the effects of fluid retention (Genotropin label). It occurs in about 2% of treated adults with GH deficiency (Molitch et al., 2011); in Genotropin's extension studies, 61 of 3,031 adults (2%) developed symptoms, which lessened after a lower dose or a pause in treatment in 52 and after surgery in 9 (Genotropin label).
• Impaired glucose tolerance / insulin resistance — Somatropin may decrease insulin sensitivity, particularly at higher doses, and can unmask impaired glucose tolerance or diabetes; new-onset type 2 diabetes has been reported (Genotropin label). In Genotropin's extension studies, 12 of 3,031 adults (0.4%) developed diabetes, all with predisposing factors (Genotropin label); in healthy older adults, GH was linked to somewhat more new diabetes and impaired fasting glucose (Liu et al., 2007).
• Gynecomastia — More common with GH than without it in trials in healthy older adults (Liu et al., 2007), and reported in healthy older people on high doses (Molitch et al., 2011); reported in children in postmarketing use (Genotropin label).
• Intracranial hypertension (pseudotumor cerebri) — Reported in a small number of patients, usually within the first 8 weeks, with papilledema, visual changes, headache, nausea or vomiting; in all reported cases it resolved quickly after treatment was stopped or the dose lowered. It is a warning on every somatropin label on DailyMed (Genotropin label).
• Scoliosis progression (pediatric) — Scoliosis can progress during rapid growth, so the labels call for monitoring children with a history of it; somatropin has not been shown to increase how often scoliosis occurs (Genotropin label).
• Slipped capital femoral epiphysis (SCFE) — Reported in children on somatropin, and more frequent in children with endocrine disorders or during rapid growth; it may lead to osteonecrosis. The labels call for evaluating any child who develops a limp or hip or knee pain (Genotropin label).
• Adrenal insufficiency unmasking — Somatropin inhibits 11β-HSD1, the enzyme that converts cortisone to active cortisol, which can lower serum cortisol; in people with, or at risk of, pituitary hormone deficiencies this can unmask central adrenal insufficiency, and people already on glucocorticoid replacement may need higher doses (Genotropin label).
• Hypothyroidism unmasking — In people with GH deficiency, central hypothyroidism may first appear or worsen on somatropin, and the labels call for periodic thyroid function tests; people with Turner syndrome have an inherently higher risk of primary hypothyroidism (Genotropin label).
• Cancer risk (epidemiologic) — Circulating IGF-1 in the upper reference range is epidemiologically associated with increased colorectal, prostate, and breast cancer risk (Pollak 2012). In KIGS, cancer was no more common than expected among 58,603 GH-treated children without cancer risk factors (Wilton et al., 2010). Active malignancy is a contraindication on the labels, and childhood cancer survivors treated with radiation to the head who later received somatropin have a higher risk of a second tumor, most often a meningioma (Genotropin label).
• Long-term overdose — Could cause the signs and symptoms of gigantism or acromegaly, the known effects of excess growth hormone (Genotropin label).
• Injection-site reactions — Reported infrequently in children's trials as pain or burning, fibrosis, nodules, rash, inflammation, pigmentation or bleeding; injecting the same site over a long time can cause lipoatrophy, which the label says rotating the site avoids (Genotropin label). Weekly somapacitan's injection-site reactions were similar to daily GH's (Johannsson et al., 2020).
• WADA-banned (S2) — Human growth hormone is prohibited at all times under WADA category S2 (peptide hormones). Detection methods include immunoassay isoform ratios (pituitary vs recombinant) and biomarker panels (P-III-NP / IGF-1). Not viable for tested athletes.
• Anabolic Steroid Control Act (21 USC §333(e)) — Under this provision, distributing human growth hormone, or possessing it with intent to distribute, for any use other than an FDA-approved one on a physician's order is a federal crime, punishable by up to 5 years in prison (10 years if the offense involves someone under 18). Off-label uses are not covered: distributing GH as an anti-aging agent is illegal in the United States (Liu et al., 2007).
• Drug interactions — The labels list insulin and other glucose-lowering drugs (doses may need adjusting); glucocorticoids (replacement doses may need raising, and high doses may blunt growth in children); thyroid hormone, which may need starting or adjusting; drugs cleared by cytochrome P450 enzymes, such as sex steroids, anticonvulsants and cyclosporine; and oral estrogen, with which a larger somatropin dose may be needed (Genotropin label). Women on oral estrogen usually need substantially higher GH doses; those on transdermal estrogen may not (Molitch et al., 2011).

Bloodwork & Monitoring

What the somatropin labels and the Endocrine Society guideline describe for monitoring:

• IGF-1 — In adults, the labels adjust the dose to clinical response and serum IGF-1, and lower it if IGF-1 rises above the age- and sex-specific normal range (Genotropin label); for weekly Sogroya, IGF-1 is drawn 3 to 4 days after the last dose (Sogroya label). The guideline monitors every 1 to 2 months while the dose is being adjusted and every 6 months after that, with a clinical assessment, side effects and IGF-1 (Molitch et al., 2011).
• Glucose and lipids — The labels call for periodic glucose checks in everyone on somatropin, and closer monitoring in people with diabetes or its risk factors (Genotropin label). The guideline adds a lipid profile and fasting glucose once a year; most, but not all, studies show LDL and total cholesterol falling and HDL rising on GH replacement (Molitch et al., 2011).
• Thyroid and adrenal function — The labels call for periodic thyroid function tests, and warn of low serum cortisol or unmasked central adrenal insufficiency in people with, or at risk of, other pituitary hormone deficiencies (Genotropin label). The guideline suggests monitoring both, with free T4 checked and thyroid-hormone doses adjusted as needed (Molitch et al., 2011).
• Eye exam — A fundoscopic exam before treatment and periodically during it, to catch papilledema from intracranial hypertension (Genotropin label).
• Bone density — If the first DXA scan is abnormal, the guideline repeats it every 1.5 to 2 years (Molitch et al., 2011).
• Tumors — The labels call for ruling out a pituitary or other brain tumor before treatment, since GH deficiency may be an early sign of one, and for routine monitoring of anyone whose GH deficiency followed an intracranial tumor (Genotropin label).

The guideline notes that its monitoring advice rests on clinical experience rather than large controlled studies (Molitch et al., 2011).

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References

1. Rudman D, Feller AG, Nagraj HS, Gergans GA, Lalitha PY, Goldberg AF, Schlenker RA, Cohn L, Rudman IW, Mattson DE. Effects of human growth hormone in men over 60 years old. N Engl J Med. 1990;323(1):1-6. PMID: 2355952. (The landmark anti-aging reference.)
2. Molitch ME, Clemmons DR, Malozowski S, Merriam GR, Vance ML; Endocrine Society. Evaluation and treatment of adult growth hormone deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(6):1587-1609. PMID: 21602453.
3. Liu H, Bravata DM, Olkin I, Nayak S, Roberts B, Garber AM, Hoffman AR. Systematic review: the safety and efficacy of growth hormone in the healthy elderly. Ann Intern Med. 2007;146(2):104-115. PMID: 17227934. (The most-cited independent appraisal of anti-aging rhGH.)
4. Johannsson G, Gordon MB, Højby Rasmussen M, Håkonsson IH, Karges W, Sværke C, Tahara S, Takano K, Biller BMK. Once-weekly somapacitan is effective and well tolerated in adults with GH deficiency: a randomized phase 3 trial. J Clin Endocrinol Metab. 2020;105(4):e1358-e1376. PMID: 32022863. (REAL1 — basis of 2020 Sogroya approval.)
5. Brown RJ, Adams JJ, Pelekanos RA, Wan Y, McKinstry WJ, Palethorpe K, Seeber RM, Monks TA, Eidne KA, Parker MW, Waters MJ. Model for growth hormone receptor activation based on subunit rotation within a receptor dimer. Nat Struct Mol Biol. 2005;12(9):814-821. PMID: 16116438.
6. Wilton P, Mattsson AF, Darendeliler F. Growth hormone treatment in children is not associated with an increase in the incidence of cancer: experience from KIGS (Pfizer International Growth Database). J Pediatr. 2010;157(2):265-270. PMID: 20400105.
7. Sävendahl L, Maes M, Albertsson-Wikland K, Borgström B, Carel JC, Henrard S, Speybroeck N, Thomas M, Zandwijken G, Hokken-Koelega A. Long-term mortality and causes of death in isolated GHD, ISS, and SGA patients treated with recombinant growth hormone during childhood in Belgium, The Netherlands, and Sweden: preliminary report of 3 countries participating in the EU SAGhE study. J Clin Endocrinol Metab. 2012;97(2):E213-E217. PMID: 22238393.
8. Pollak M. The insulin and insulin-like growth factor receptor family in neoplasia: an update. Nat Rev Cancer. 2012;12(3):159-169. PMID: 22337149. (IGF-1 and cancer epidemiology — central safety-framing source.)
9. Mauras N, Attie KM, Reiter EO, Saenger P, Baptista J; Genentech, Inc Cooperative Study Group. High dose recombinant human growth hormone (GH) treatment of GH-deficient patients in puberty increases near-final height: a randomized, multicenter trial. J Clin Endocrinol Metab. 2000;85(10):3653-3660. PMID: 11061518.
10. Grinspoon S, Mulligan K; Department of Health and Human Services Working Group on the Prevention and Treatment of Wasting and Weight Loss. Weight loss and wasting in patients infected with human immunodeficiency virus. Clin Infect Dis. 2003;36(Suppl 2):S69-S78. PMID: 12652374. (Context for Serostim / AIDS-wasting indication.)
11. Cook DM, Yuen KC, Biller BM, Kemp SF, Vance ML; American Association of Clinical Endocrinologists. American Association of Clinical Endocrinologists medical guidelines for clinical practice for growth hormone use in growth hormone-deficient adults and transition patients — 2009 update. Endocr Pract. 2009;15(Suppl 2):1-29. PMID: 20228036.
12. Powers ME. The safety and efficacy of anabolic steroid precursors: what is the scientific evidence? J Athl Train. 2002;37(3):300-305. PMID: 16558675. (Context for Anabolic Steroid Control Act and GH legal framework.)
13. U.S. Food and Drug Administration. Genotropin (somatropin) Prescribing Information. Pfizer Inc.
14. U.S. Food and Drug Administration. Norditropin (somatropin) Prescribing Information. Novo Nordisk Inc.
15. U.S. Food and Drug Administration. Sogroya (somapacitan) Prescribing Information. Novo Nordisk. First approved 2020.
16. U.S. Food and Drug Administration. Skytrofa (lonapegsomatropin-tcgd) Prescribing Information. Ascendis Pharma. First approved 2021.
17. 21 U.S.C. §333(e) — Anabolic Steroid Control Act, human growth hormone provision. U.S. Code.
18. WADA. 2026 World Anti-Doping Code Prohibited List. Section S2 — Peptide hormones, growth factors, related substances and mimetics. World Anti-Doping Agency. (rhGH S2 prohibition and detection methods.)
19. FDA. Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the FD&C Act (503A categories list), versions updated April 15, April 22 and May 14, 2026. fda.gov/media/94155/download. Read October 3, 2026. (Notice that 12 peptides would leave Category 2 because their nominations were withdrawn; their removal; GHK-Cu, except injectable, back in Category 1.)
20. Eli Lilly and Company. Humatrope (somatropin) for injection prescribing information. DailyMed set ID a774e1ae-3997-49ee-8b0e-99a2b315d409 (SPL version 45, effective August 20, 2026). dailymed.nlm.nih.gov. Read October 3, 2026.
21. Sandoz Inc. Omnitrope (somatropin) injection and for injection prescribing information. DailyMed set ID 58d84ffa-4056-4e36-ad67-7bd4aef444a5 (SPL version 36, effective July 10, 2025). dailymed.nlm.nih.gov. Read October 3, 2026.
22. EMD Serono, Inc. Serostim (somatropin) for injection prescribing information. DailyMed set ID 62b01d29-90f0-45b2-a0c4-3a750ba36c8a (SPL version 15, effective September 22, 2026). dailymed.nlm.nih.gov. Read October 3, 2026.
23. EMD Serono, Inc. Saizen (somatropin) for injection prescribing information, revised May 2017 (BLA 019764). accessdata.fda.gov/drugsatfda_docs/label/2017/019764s086lbl.pdf. Read October 3, 2026. (The most recent Saizen label on Drugs@FDA; DailyMed lists no current Saizen label.)
24. Serono, Inc. Zorbtive (somatropin) for injection prescribing information, approved December 1, 2003 (BLA 021597). accessdata.fda.gov/drugsatfda_docs/label/2003/20604s026_zorbtive_lbl.pdf. Read October 3, 2026. (The only Zorbtive label on Drugs@FDA; DailyMed lists no current Zorbtive label.)
25. Thornton PS, Maniatis AK, Aghajanova E, Chertok E, Vlachopapadopoulou E, Lin Z, et al. Weekly lonapegsomatropin in treatment-naïve children with growth hormone deficiency: the phase 3 heiGHt trial. J Clin Endocrinol Metab. 2021;106(11):3184-3195. PMID: 34272849.
26. Blackman MR, Sorkin JD, Münzer T, Bellantoni MF, Busby-Whitehead J, Stevens TE, et al. Growth hormone and sex steroid administration in healthy aged women and men: a randomized controlled trial. JAMA. 2002;288(18):2282-2292. PMID: 12425705.

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