Peptide Hormone / SubQ, IM / 2-6 IU daily
HGH (Somatropin)
Growth hormone reached patients as a scarce extract of cadaver pituitaries and stayed that way for 27 years, because hormone from cattle and pigs does not work in humans. Recombinant DNA ended the shortage in 1985, the same year the cadaver-derived product was withdrawn for transmitting Creutzfeldt-Jakob disease.
In plain words
HGH, sold as somatropin, is a lab-made copy of human growth hormone, the 191-amino-acid protein the pituitary gland normally releases in about a dozen short bursts a day. It is a licensed medicine for people who do not make enough of it and for wasting in HIV, and randomized trials in those groups found it raised lean tissue. In healthy adults the effect is much smaller: a review of randomized trials in older adults found roughly 2.1 kg of fat traded for about the same weight of lean tissue with no change in total weight, and in trained adults strength, power and endurance did not improve at all, while a small sprint gain was gone six weeks after stopping. The older-adult trials also found more swelling, joint pain, carpal tunnel syndrome and breast tissue growth in men, and somewhat more impaired fasting glucose or diabetes. Until 1985 the only source was hormone extracted from pituitaries collected at autopsy, and distribution stopped that year after recipients died of Creutzfeldt-Jakob disease; the unregulated kits sold today contain the same well-characterized protein, but nobody in that chain checks its strength, its clumped-protein content, or contamination.
At a glance
| Half-life | 0.17 days |
|---|---|
| Tmax | 0.22 days |
| Route(s) | SubQ, IM |
| Published dosing range | 2-6 IU daily |
| Vial strengths | 10, 12, 15, 36 IU |
Reference data from the DosePlot canon -- not a protocol recommendation.
Serum curve
Single 4 IU dose by SubQ, rendered from the same engine that powers the interactive chart. Relative levels, not lab values.
What does the evidence show?
Two things are labeled separately here because they answer different questions. The tier is how a study was built. The distance chips are whether that study touched this molecule, by this route, in a population resembling the reader. A randomized trial of a different molecule keeps its tier and still says nothing about this compound.
| Finding | Tier | Distance from use | Study |
|---|---|---|---|
| Six months of nightly subcutaneous growth hormone in adults with growth hormone deficiency raised mean plasma IGF-1 from 0.41 to 1.53 U/L and shifted body composition toward lean mass, in a double-blind placebo-controlled trial of 24 patients. | rct | not recorded | Salomon F, Cuneo RC, Hesp R, Sonksen PH. The effects of treatment with recombinant human growth hormone on body composition and metabolism in adults with growth hormone deficiency.New England Journal of Medicine 321(26):1797-1803, 1989 |
| A systematic review of randomized trials in healthy older adults, 31 articles describing 18 unique study populations, in which 220 participants completed growth hormone treatment (mean 27 weeks), found about 2.1 kg of fat mass traded for about 2.1 kg of lean mass with no significant change in total weight. Treated participants were significantly more likely to have soft-tissue edema, joint pain, carpal tunnel syndrome, and gynecomastia, and somewhat more likely to develop impaired fasting glucose or diabetes. | rct | not recorded | 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.Annals of Internal Medicine 146(2):104-115, 2007 |
| Adding growth hormone to 12 weeks of heavy resistance training in young men increased fat-free mass and whole-body protein synthesis more than training alone, but did not increase quadriceps muscle protein synthesis, limb circumference, or strength; the authors concluded the extra fat-free mass was lean tissue other than skeletal muscle. | rct | not recorded | Yarasheski KE, Campbell JA, Smith K, Rennie MJ, Holloszy JO, Bier DM. Effect of growth hormone and resistance exercise on muscle growth in young men.American Journal of Physiology 262(3 Pt 1):E261-E267, 1992 |
| In 96 recreationally trained adults, eight weeks of growth hormone reduced fat mass and raised lean body mass through an increase in extracellular water, and increased sprint capacity by 3.9 percent, while endurance, strength, and power did not change; the sprint gain was gone six weeks after stopping. | rct | not recorded | Meinhardt U, Nelson AE, Hansen JL, Birzniece V, Clifford D, Leung KC, Graham K, Ho KK. The effects of growth hormone on body composition and physical performance in recreational athletes: a randomized trial.Annals of Internal Medicine 152(9):568-577, 2010 |
| In HIV-associated wasting, 12 weeks of growth hormone at 0.1 mg/kg daily increased body weight by 1.6 kg and lean body mass by 3.0 kg against 0.1 kg and -0.1 kg on placebo, and raised treadmill work output. Wasting is one of the indications somatropin is actually licensed for. | rct | not recorded | Schambelan M, Mulligan K, Grunfeld C, Daar ES, LaMarca A, Kotler DP, Wang J, Bozzette SA, Breitmeyer JB. Recombinant human growth hormone in patients with HIV-associated wasting. A randomized, placebo-controlled trial.Annals of Internal Medicine 125(11):873-882, 1996 |
| Splitting the same intravenous dose into eight small boluses and infusing it continuously raised IGF-1 to nearly identical areas under the curve in growth hormone deficient patients (147.6 and 151.2 mcg/L), both above two large boluses (125.3 mcg/L). For IGF-1, how widely the dose was spread mattered more than whether it arrived in pulses. | clinical | not recorded | Jorgensen JO, Moller N, Lauritzen T, Christiansen JS. Pulsatile versus continuous intravenous administration of growth hormone (GH) in GH-deficient patients: effects on circulating insulin-like growth factor-I and metabolic indices.Journal of Clinical Endocrinology and Metabolism 70(6):1616-1623, 1990 |
| In rodents the pattern of growth hormone exposure is itself a signal: pulses drive the male-type program of liver gene expression through STAT5b, while continuous exposure drives the female-type program. Whether pattern sensitivity of this kind matters at human therapeutic doses has not been demonstrated. | preclinical | not recorded | Waxman DJ, O'Connor C. Growth hormone regulation of sex-dependent liver gene expression.Molecular Endocrinology 20(11):2613-2629, 2006 |
| Community reports describe the first weeks on low daily doses in terms of deeper sleep, skin and nail changes, and puffiness or tingling in the hands, and describe moving the dose to bedtime or splitting it to reduce the morning fluid symptoms. These are self-reports without measurement, and the fluid and carpal tunnel symptoms are the same adverse events the controlled trials record. | anecdotal | not recorded | community reports aggregated from reddit, MESO-Rx, and similar forumsno study |
How did it get here?
- preclinical1920s-1950s
- Pituitary extracts are shown to drive growth in laboratory animals and the active protein is eventually isolated. Growth hormone from cattle and pigs turns out to be inert in humans, which narrows the only usable source to primate pituitary tissue.
- first-human1958
- Maurice Raben reports treating a 17-year-old with pituitary dwarfism using hormone extracted from autopsy pituitaries with glacial acetic acid. Growth resumed. His program at Tufts had begun giving the extract in 1956, and the regimen in the 1958 report is not available in any open-access source.
- clinical-adoption1963-1985
- The US National Hormone and Pituitary Program collects pituitaries at autopsy and distributes the extract to roughly 7,700 children. Supply is counted in glands, so treatment is rationed and adults with the same deficiency are not treated at all.
- clinical-adoption1985
- Distribution stops after three recipients die of Creutzfeldt-Jakob disease. A 2012 final assessment of iatrogenic cases counted 29 US cases and 226 worldwide linked to cadaver-derived hormone, and a 2025 report from the agencies that follow the cohort puts the US total at 36; in the United States no case has occurred in a patient who started treatment after a 1977 change in purification. The cohort is still followed, so the count is a running one. The FDA approves the first recombinant version the same year, and the supply problem ends permanently.
- grey-market1990
- A study of 21 healthy men over 60, 12 of them treated for six months, reports an 8.8 percent gain in lean body mass and a 14.4 percent fall in fat mass. It is read as an anti-aging result and creates a market. Congress writes a distribution offense specific to growth hormone into federal law the same year.
- grey-market1990s-present
- Recombinant somatropin from unregulated manufacturers reaches consumers as lyophilized kits. The protein is the same well-characterized 191-amino-acid sequence a licensed product contains; what nobody in the chain verifies is potency against the international standard, aggregate content, and endotoxin.
How is it made?
Production happens in four stages.
1. Building the gene and the cell. Human growth hormone is a single chain of 191 amino acids with two disulfide bonds. Manufacturers do not extract it: they write a synthetic gene for that sequence and put it into Escherichia coli or a mammalian cell line. In the bacterial route a short leader on the gene pushes the chain into the periplasm, where it is clipped off, leaving the authentic sequence. The first recombinant product, approved in 1985, skipped that step and carried an extra methionine.
2. Fermentation and folding. Cells grow in stirred tanks on a defined feed, then are harvested and broken open. Sequence alone does not finish a protein: the two disulfide bonds have to form in the correct pairing, or the molecule is inactive or becomes a variant the immune system can learn to attack.
3. Purification. Chromatography steps separate correctly folded monomer from host-cell protein, endotoxin, aggregates, and deamidated forms that differ from the intended molecule by one amide group.
4. Filling. Most somatropin is freeze-dried with a bulking agent and buffer salts, sealed in vials or pen cartridges, and reconstituted by the user. Potency is assigned against an international reference standard, not by weight.
What separates a good batch from a bad one is analytical: aggregate content, host-cell protein, endotoxin, and potency against the standard. Those tests, and the sterile fill, are what vary outside regulated manufacturing, and the white cake in the vial looks the same either way.
Worth knowing
Growth hormone from cattle and pigs is essentially inert in humans, and the reason is one amino acid: arginine 43 in the human receptor is incompatible with the histidine that non-primate growth hormones carry at position 171. Swapping that residue into a bovine receptor cut its affinity for bovine hormone 200-fold. That single incompatibility is why the world had to harvest human pituitaries at autopsy until recombinant DNA arrived.
Souza SC, Frick GP, Wang X, Kopchick JJ, Lobo RB, Goodman HM. A single arginine residue determines species specificity of the human growth hormone receptor.Proceedings of the National Academy of Sciences USA 92(4):959-963, 1995
Human growth hormone is not a scheduled controlled substance in the United States, yet it has its own federal distribution offense. A 1990 statute makes knowingly distributing it for a use other than a disease or recognized medical condition authorized by the Secretary of Health and Human Services, on a physician's order, punishable by up to five years, and ten years if the offense involves someone under 18. A conviction counts as a felony violation of the Controlled Substances Act for one purpose only, forfeiture. The Drug Enforcement Administration is authorized to investigate the offense even though the drug itself sits on no schedule.
Perls TT, Reisman NR, Olshansky SJ. Provision or distribution of growth hormone for 'antiaging': clinical and legal issues.JAMA 294(16):2086-2090, 2005
Somatropin is one of the few injectables still dosed in international units by habit rather than necessity. The current WHO International Standard, ampoule code 98/574, is defined at 3.0 IU per mg, so 4 IU is 1.33 mg. Its predecessor, the first somatropin standard, was defined at the same 3.0 IU per mg and 98/574 was calibrated against it, so the somatropin conversion has not moved between standards. Potency is assigned against that ampoule rather than by weighing the powder: WHO fixed its content at 1.95 mg of somatropin and somatropin-related proteins.
Bristow AF, Jespersen AM. The Second International Standard for somatropin (recombinant DNA-derived human growth hormone): preparation and calibration in an international collaborative study.Biologicals 29(2):97-106, 2001
Reconstitution
HGH (Somatropin) ships lyophilized and is mixed before use; the published vial strengths are 10, 12, 15, 36 IU. The water volume you add sets the concentration, not the dose -- the calculator turns a vial size and a water volume into mg/mL, draw volume, and units on an insulin syringe.
Open in the reconstitution calculatorWritten and reviewed by Evan Marlow, developer of DosePlot · Updated 2026-08-27
Not medical advice. DosePlot is an informational tool, not a healthcare provider, and using it creates no provider-patient relationship. Do not start, stop, or change any protocol without the approval of a licensed healthcare professional.
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