HGH (human growth hormone), sold as somatropin, is a prescription drug that the FDA has approved for children and adults with growth hormone deficiency and for a few rare conditions.[1] “HGH 191AA” is not a separate drug; it refers to the 191-amino-acid protein that every daily somatropin brand contains.[1] Trials in healthy older adults found small gains in lean mass along with frequent swelling and joint pain.[21] In the US, distributing HGH for anti-aging or bodybuilding is a federal crime.[26]
This profile covers what HGH is, its approved uses, what trials show in adults, dosing on the labels, side effects, how it compares with growth hormone peptides, and the law.
What is HGH (and what does 191AA mean)?
Growth hormone is made by the pituitary gland. Drug-grade HGH works like pituitary growth hormone: in children with deficiency it stimulates growth and normalizes IGF-1, and in adults with deficiency it reduces fat mass and increases lean mass.[1] Drug-grade HGH is made with recombinant DNA technology. Each daily brand is described on its label as a protein of 191 amino acids, with a sequence identical to pituitary growth hormone.[1][2][3] That is where the “191AA” label used by online sellers comes from. It does not describe a stronger or different product.
The FDA has approved several brands of daily somatropin:
- Genotropin (Pfizer): growth hormone deficiency in children and adults, Prader-Willi syndrome, children born small for gestational age, Turner syndrome and idiopathic short stature.[1]
- Norditropin (Novo Nordisk): the same pediatric uses plus Noonan syndrome, and adult growth hormone deficiency.[2]
- Humatrope (Lilly) and Zomacton (Ferring): pediatric uses including SHOX deficiency, plus adult growth hormone deficiency.[3][5]
- Omnitrope (Sandoz): the same uses as Genotropin.[4]
- Nutropin AQ (Genentech): still listed as a prescription product by FDA.[16]
- Serostim (EMD Serono): HIV-associated wasting in adults on antiretroviral therapy.[6]
- Zorbtive (EMD Serono): short bowel syndrome in people on specialized nutritional support.[7]
Three long-acting, once-weekly options followed: Sogroya (somapacitan, approved for adults in 2020 and now also for children),[13][8] Skytrofa (lonapegsomatropin, approved for children in 2021 and now also for adults),[14][9] and Ngenla (somatrogon, approved for children aged 3 and older in 2023).[15][10]
HGH benefits: what the research shows
In adults with growth hormone deficiency
This is where the evidence is strongest. A meta-analysis of 37 blinded, placebo-controlled trials found that treatment raised lean mass by 2.7 kg, cut fat by 3.1 kg, and lowered LDL cholesterol and diastolic blood pressure, but it also raised fasting glucose and insulin.[18] The Endocrine Society guideline says treatment improves body composition, exercise capacity, bone and quality of life, mostly in people with more severe deficiency. It also says the diagnosis usually needs a stimulation test.[17] In the REAL 1 trial of 301 adults, once-weekly Sogroya reduced truncal fat more than placebo, with side effects similar to daily growth hormone.[19]
Research from Russian-language journals agrees. A 2019 review from Russia’s Endocrinology Research Centre noted that treatment starts at the lowest dose to limit side effects. It added that meta-analyses have not shown a higher cancer risk with replacement in adults.[29] A small Lithuanian study (published in Russian) gave 18 adults with childhood-onset pituitary failure a low daily dose for a year; lean and water mass rose while fat mass did not change.[30]
In healthy older adults (anti-aging use)
The anti-aging interest goes back to a 1990 study of 21 men aged 61 to 81, 12 of whom received HGH. Six months of HGH raised lean mass by 8.8% and cut fat by 14.4%.[20] Larger studies have been less encouraging:
- 2007 systematic review (Liu et al.): across 18 study groups, fat fell 2.1 kg and lean mass rose 2.1 kg, and body weight did not change. Swelling, joint pain, carpal tunnel syndrome and breast enlargement were more common, and diabetes was somewhat more common. The authors concluded HGH “cannot be recommended as an antiaging therapy.”[21]
- 2002 JAMA trial: in 131 people aged 65 to 88, HGH added lean mass, but strength barely changed. Swelling affected 39% of women on HGH, and diabetes or glucose intolerance developed in 18 men on HGH versus 7 not on it.[22]
In athletes and bodybuilders
- 2008 systematic review: HGH raised lean mass by 2.1 kg in young, fit people, but strength and exercise capacity did not seem to improve, and swelling and fatigue were more common.[23]
- 2010 trial in 96 recreational athletes: 2 mg a day for 8 weeks raised lean mass, mostly through extra body water. Sprint capacity rose by 3.9%, but strength, power and endurance did not change, and the sprint gain faded 6 weeks after stopping.[24]
HGH dosage
Doses on the labels are set by a doctor based on weight, age, growth response and IGF-1 levels. For Genotropin, the weekly dose is split into 6 or 7 injections.[1] For converting milligrams to syringe units, see our peptide calculator.
| Use (label) | Dose |
|---|---|
| Pediatric growth hormone deficiency (Genotropin) | 0.16 to 0.24 mg/kg per week[1] |
| Turner syndrome (Genotropin) | 0.33 mg/kg per week[1] |
| Adult growth hormone deficiency (Genotropin) | Start about 0.2 mg/day (0.15 to 0.30), increase by 0.1 to 0.2 mg/day every 1 to 2 months[1] |
| HIV wasting (Serostim) | About 0.1 mg/kg once daily at bedtime, up to 6 mg[6] |
| Sogroya, children with deficiency | 0.16 mg/kg once weekly[8] |
| Skytrofa, children | 0.24 mg/kg once weekly[9] |
| Ngenla, children | 0.66 mg/kg once weekly[10] |
Anti-aging and bodybuilding doses are not on any label. In the 2010 athlete trial, 2 mg a day was used, which the authors said may be lower than what some athletes use covertly.[24]
HGH side effects
In Genotropin trials in adults with growth hormone deficiency, these effects were more common than with placebo during the first 6 months:[1]
| Side effect | HGH | Placebo |
|---|---|---|
| Peripheral swelling | 17.5% | 5.1% |
| Joint pain (arthralgia) | 17.3% | 4.2% |
| Pain in arms or legs | 14.7% | 5.9% |
| Edema | 10.8% | 2.6% |
| Tingling or numbness | 9.6% | 1.9% |
| Stiffness of arms or legs | 7.9% | 1.6% |
These were mostly mild, appeared early and often eased with a lower dose.[1] Other risks on the labels:
- Carpal tunnel syndrome: 2% of 3,031 adults treated with Genotropin developed symptoms, which improved with a lower dose, a pause or surgery.[1]
- Blood sugar: HGH can reduce insulin sensitivity and unmask diabetes. In the same group of 3,031 adults, 0.4% developed diabetes, all with existing risk factors.[1]
- Critical illness: in two trials of very ill adults after surgery or trauma, deaths were higher on high-dose somatropin (41.9% vs 19.3%), so it is not used in acute critical illness.[7]
- Other warnings: raised pressure in the skull, pancreatitis, low thyroid or cortisol levels, and growth of existing tumors. HGH is not used with active cancer.[1]
- Prader-Willi syndrome: sudden deaths have been reported in children who were severely obese or had breathing problems.[1]
HGH vs growth hormone peptides
HGH replaces growth hormone directly. Peptides such as sermorelin, tesamorelin and CJC-1295 with DAC instead prompt the pituitary to release more of its own, and MK-677 is a pill that does the same through the ghrelin receptor. A 2026 review of growth hormone-axis peptides placed only tesamorelin in its top tier, with regulatory-grade trial data, while others such as CJC-1295 without DAC had no peer-reviewed human studies.[28] HGH itself has decades of approved use, but only for specific diagnoses.[1] For combined peptide use, see our CJC-1295 and ipamorelin guide.
Is HGH legal?
- Prescription only: HGH is approved for specific medical conditions, and the labels say a doctor experienced in growth hormone deficiency should supervise treatment.[1]
- Anti-aging use is illegal to supply: under 21 U.S.C. 333(e), knowingly distributing HGH, or possessing it with intent to distribute, for anything other than an FDA-authorized treatment ordered by a doctor carries up to 5 years in prison, or 10 years if someone under 18 is involved. The law covers somatropin and its analogs.[26] A 2005 JAMA article reviewed the clinical and legal problems with prescribing HGH for “antiaging”.[25]
- Banned in sport: WADA lists growth hormone, its analogs (including lonapegsomatropin, somapacitan and somatrogon) and fragments under S2, prohibited at all times.[27]
This is general information, not legal advice.
