HGH 191AA: What It Is, Dosage and Legal Status
HGH 191AA is research-sold somatropin - the same molecule as FDA-approved growth hormone drugs, sold outside the prescription system.
The short version
HGH 191AA is a research-market name for somatropin, the lab-made 191-amino-acid human growth hormone in several FDA-approved prescription drugs. The molecule is well studied for its approved uses. A vial sold online as "HGH 191AA" comes from outside the pharmacy supply chain, with no FDA review of its contents, and is marketed for muscle, recovery and anti-aging uses that were never the basis of approval.
- HGH 191AA and prescription somatropin are the same molecule; what differs is the supply chain and the review behind the vial.
- 1 mg of somatropin equals 3 IU on the FDA Omnitrope label: two units for the same amount.
- Approved products are dosed for growth hormone deficiency and related conditions; research vials are marketed for uses the approval trials never tested.
- Common research-channel practice is 1-4 IU (roughly 333 mcg-1.3 mg) once daily: not an FDA dose, and unverified for an unregulated vial.
HGH 191AA at a glance
- What it is
- Recombinant 191-amino-acid human growth hormone - the same active molecule (somatropin) sold under FDA-approved brand names, here sold outside the prescription supply chain as an unverified research chemical
- Main use
- Marketed to consumers for body recomposition, recovery and anti-aging in adults who do not have a diagnosed growth hormone deficiency. The identical molecule, somatropin, is FDA-approved by prescription for defined deficiency and wasting conditions - see the "Where approved somatropin fits" section on the main guide for that distinction.
- Generic name
- somatropin
- Brand names
- Genotropin (Pfizer), Humatrope (Eli Lilly), Norditropin (Novo Nordisk), Omnitrope (Sandoz), Zomacton (Ferring Pharmaceuticals) and Serostim (EMD Serono) Label
- Also called
- rHGH, 191-amino acid recombinant human growth hormone, Human Growth Hormone (research-sold)
- Size
- 191 amino acids Details
- Evidence
- Limited human data
- US status
- Research use only
- Half-life
- Not verified for the research-sold product this session; approved-product labels report pharmacokinetics for the specific formulation studied, not for an unverified vial.
- How it is taken
- Subcutaneous injection
- Common protocol
- 333-1333 mcg, Once daily (split into a morning and evening dose above roughly 3 IU/day), subcutaneous, for 12-24 weeks (common practice, not trial-established) Dosage chart
“HGH 191AA” is a research-market name for somatropin, the same 191-amino-acid growth hormone sold by prescription in several FDA-approved drugs. The molecule isn’t the grey area; the supply chain is. Dosing: common research-channel practice, and the FDA label dose for comparison.
What is HGH 191AA?
Human growth hormone is a 191-amino-acid protein made by the pituitary gland. Somatropin is the lab-made (recombinant) version with the same sequence. It is the active ingredient in several FDA-approved drugs, including Omnitrope, Norditropin and Humatrope, each with its own label, formulation and injection device.
“HGH 191AA” is what research-chemical vendors call somatropin sold as a freeze-dried powder outside that prescription system. It is usually labelled research use only or not for human use.
Small or uncontrolled human studies. Too little to settle the question either way. Somatropin has strong clinical-trial evidence for its FDA-approved uses, growth hormone deficiency and related conditions, reflected in the approved labels. None of that evidence comes from healthy adults using it for muscle, recovery or anti-aging, and no trial has tested a research-channel HGH 191AA product itself.
HGH 191AA structure
- Length
- 191 amino acids
- Modifications
- Single 191-residue chain (mature human growth hormone, UniProt chain 27-217) with two disulfide bonds.
A protein of about 22 kDa, too large for a meaningful 2D diagram and with no PubChem compound record. Somatropin is identical in sequence to natural human growth hormone, so the UniProt entry for the natural protein describes it.
Sequence checked against FDA prescribing information (Norditropin), DailyMed.
HGH 191AA benefits: what the research shows
How growth hormone works is well understood. It binds its receptor and drives the liver to make IGF-1, which carries most of its growth and metabolic effects. Growth hormone also breaks down fat directly and works against insulin. That is established pharmacology behind the approved labels.
No trial has tested whether a self-sourced HGH 191AA vial delivers what it is marketed for in a healthy adult without a diagnosed deficiency. Those claims are fat loss, muscle gain, faster recovery and slower aging. The trials behind somatropin’s approval were run in people with deficiency or wasting, under medical supervision, with a verified product and a monitored dose. None of that carries over to an unregulated vial used without supervision.
HGH 191AA dosage
The common HGH 191AA dose is 333-1333 mcg, Once daily (split into a morning and evening dose above roughly 3 IU/day), subcutaneous. From a 5 mg vial mixed with 2 mL of bacteriostatic water, 850 mcg is 34 units (0.34 mL) on a U-100 insulin syringe.
Growth hormone doses are written in International Units (IU) as often as in milligrams. The two describe the same amount, not different strengths. The FDA’s Omnitrope label gives cartridge strength in both: 5 mg/1.5 mL (15 IU) and 10 mg/1.5 mL (30 IU). That makes 1 mg = 3 IU, or about 333 mcg per IU.
Not every current US label gives an IU figure. Norditropin’s label, for example, doses in mg and mg/kg only, with no IU conversion anywhere on it. Full sourcing, the FDA label dose and the research-channel figures: HGH 191AA dosage.
Where approved somatropin fits
For growth hormone deficiency and a few other defined conditions, somatropin is an FDA-approved prescription medicine. A patient gets an FDA-reviewed formulation, a starting dose adjusted to their blood tests and response, and ongoing monitoring for the effects in the label’s warnings.
None of that resembles buying a freeze-dried vial online. If growth hormone deficiency, or another condition an approved label covers, is a real possibility, talk to a prescribing clinician about an approved product.
HGH 191AA side effects
Nobody has studied side effects of research-sold vials. What is documented is the warning list on approved labels, written for a monitored, correctly dosed, FDA-reviewed product:
- fluid retention and swelling (edema)
- joint pain (arthralgia)
- carpal tunnel syndrome
- glucose intolerance and diabetes risk
- raised pressure inside the skull (intracranial hypertension)
- in people with a history of cancer, a warning about tumor recurrence or progression
- in children, slipped capital femoral epiphysis (a hip-joint problem) and worsening scoliosis
A self-sourced vial comes with none of that monitoring. It also carries its own risk: no regulator checks its purity, actual dose or sterility.
Is HGH 191AA legal?
US legal status - Research use only
Sold for laboratory research use only. Not approved by the FDA for human use, and cannot be lawfully marketed as a supplement or a medicine. Products sold this way are not made to pharmaceutical quality standards, and their contents are not verified by anyone.
- The molecule is FDA-approved by prescription, in several branded somatropin products, for defined deficiency and wasting conditions.
- A vial sold as “HGH 191AA” is not one of those products. It reaches buyers outside the pharmacy supply chain, usually labelled research use only, with no FDA review of its identity, purity or dose.
- Banned at all times in sport under WADA’s Prohibited List, section S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics), which names growth hormone explicitly.
Related reading
- MGF - a different growth-factor peptide, downstream of the same GH-IGF-1 signalling idea
- PEG-MGF - the PEGylated version of MGF
- CJC-1295 - raises GH indirectly via the GHRH receptor, rather than supplying GH itself
- Research peptides and the law
Regulatory changes for this compound and others, as they happen: US peptide regulation tracker.
How HGH 191AA compares
Growth hormone and growth factors. Doses for unapproved compounds are common practice, not trial-established. All growth hormone and muscle peptides →
| Compound | Main use | Evidence | Usual dose | US status |
|---|---|---|---|---|
| HGH 191AA | Marketed to consumers for body recomposition, recovery and anti-aging in adults who do not have a diagnosed growth hormone deficiency. The identical molecule, somatropin, is FDA-approved by prescription for defined deficiency and wasting conditions - see the "Where approved somatropin fits" section on the main guide for that distinction. | Limited human data | 333-1333 mcg, Once daily (split into a morning and evening dose above roughly 3 IU/day), subcutaneous | Research use only |
| IGF-1 LR3 | Originally engineered as a laboratory reagent - an IGF-1 variant with reduced binding to IGF-binding proteins, used to study IGF-1 signalling in cell culture. Sold to consumers as a research chemical for muscle growth, a use with no controlled human trial behind it. | Animal / lab only | 20-50 mcg, once daily | Research use only |
| IGF-1 DES | Originally isolated and studied as a naturally occurring IGF-1 fragment in laboratory pharmacology, used to probe IGF-1 receptor signalling with reduced interference from binding proteins. Sold to consumers as a research chemical for localised, site-specific muscle growth, a use with no controlled human trial behind it. | Animal / lab only | 20-120 mcg, on training days only, about 4-5 times a week, not on rest days | Research use only |
| MGF | Marketed to consumers as a peptide injected directly into a trained muscle immediately after exercise, for local muscle repair and growth. No completed human trial has tested it for this or any outcome. | Animal / lab only | 100-400 mcg, Immediately post-workout, 2-3 times a week (training days only) | Research use only |
| PEG-MGF | Marketed to consumers for muscle repair and growth after resistance training. Never approved for human use; FDA states it has identified no human exposure data on it by any route. | Animal / lab only | 200-400 mcg, 2-3 times a week, post-workout | Research use only |
| Follistatin | The body's own brake on activin and myostatin signalling, studied academically as a gene-therapy payload for muscle-wasting disease. Sold separately, as an injected research-chemical protein, for grey-market muscle-building use that its own human trials have never tested. | Animal / lab only | 100-500 mcg, 2 to 4 times a week | Research use only |
Where to buy HGH 191AA for research
Each vendor is checked against my vendor checklist.
I don't list a vendor for HGH 191AA yet. Before buying from anyone, work through the vendor checklist.
Common questions
Is HGH 191AA the same as real HGH?
The sequence is meant to be identical to human growth hormone and to the somatropin in approved drugs. The practical difference is that no regulator checks whether a research vial contains it, at the labelled strength and without contaminants.
What is the usual HGH 191AA dose?
Research-community sources describe roughly 1-4 IU (about 333 mcg-1.3 mg) injected under the skin once daily, in 12-24 week cycles with a 4-8 week break. That is common practice, not a trial or FDA dose. The dosing page compares it with the FDA label dose for approved somatropin.
What are the side effects of HGH 191AA?
There are no side-effect data for research vials. FDA labels for approved somatropin warn of fluid retention, carpal tunnel syndrome, joint pain, glucose intolerance and diabetes risk, and tumor growth in people with existing tumors. Those apply to a monitored, correctly dosed, verified product, not a self-sourced vial of unknown purity.
What is the brand name of somatropin?
Somatropin is sold under the brand names Genotropin, Humatrope, Norditropin, Omnitrope, Zomacton and Serostim. Genotropin is approved for growth failure in children due to growth hormone deficiency, Prader-Willi syndrome, being born small for gestational age, Turner syndrome or idiopathic short stature, and growth hormone deficiency in adults. Humatrope is approved for growth failure or short stature in children due to growth hormone deficiency, Turner syndrome, idiopathic short stature, SHOX deficiency or being born small for gestational age, and growth hormone deficiency in adults. Norditropin is approved for growth failure or short stature in children due to growth hormone deficiency, Noonan syndrome, Turner syndrome, being born small for gestational age, idiopathic short stature or Prader-Willi syndrome, and growth hormone deficiency in adults. Omnitrope is approved for growth failure in children due to growth hormone deficiency, Prader-Willi syndrome, being born small for gestational age, Turner syndrome or idiopathic short stature, and growth hormone deficiency in adults. Zomacton is approved for growth failure or short stature in children due to growth hormone deficiency, Turner syndrome, idiopathic short stature, SHOX deficiency or being born small for gestational age, and growth hormone deficiency in adults. Serostim is approved for HIV-associated wasting or cachexia in adults, to increase lean body mass, body weight and physical endurance (with antiretroviral therapy).
What is the generic name for Genotropin?
The generic name for Genotropin is somatropin. Genotropin is Pfizer's brand, approved for growth failure in children due to growth hormone deficiency, Prader-Willi syndrome, being born small for gestational age, Turner syndrome or idiopathic short stature, and growth hormone deficiency in adults.
What is the generic name for Humatrope?
The generic name for Humatrope is somatropin. Humatrope is Eli Lilly's brand, approved for growth failure or short stature in children due to growth hormone deficiency, Turner syndrome, idiopathic short stature, SHOX deficiency or being born small for gestational age, and growth hormone deficiency in adults.
What is the generic name for Norditropin?
The generic name for Norditropin is somatropin. Norditropin is Novo Nordisk's brand, approved for growth failure or short stature in children due to growth hormone deficiency, Noonan syndrome, Turner syndrome, being born small for gestational age, idiopathic short stature or Prader-Willi syndrome, and growth hormone deficiency in adults.
What is the generic name for Omnitrope?
The generic name for Omnitrope is somatropin. Omnitrope is Sandoz's brand, approved for growth failure in children due to growth hormone deficiency, Prader-Willi syndrome, being born small for gestational age, Turner syndrome or idiopathic short stature, and growth hormone deficiency in adults.
What is the generic name for Zomacton?
The generic name for Zomacton is somatropin. Zomacton is Ferring Pharmaceuticals's brand, approved for growth failure or short stature in children due to growth hormone deficiency, Turner syndrome, idiopathic short stature, SHOX deficiency or being born small for gestational age, and growth hormone deficiency in adults.
What is the generic name for Serostim?
The generic name for Serostim is somatropin. Serostim is EMD Serono's brand, approved for HIV-associated wasting or cachexia in adults, to increase lean body mass, body weight and physical endurance (with antiretroviral therapy).
References (7 sources)
Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.
- 1.FDA label (Omnitrope, somatropin [rDNA origin] injection) - cartridge strengths given in both mg and IU (5 mg/1.5 mL (15 IU); 10 mg/1.5 mL (30 IU)); adult and pediatric dosing in section 2.- US Food and Drug Administrationlabel
- 2.GENOTROPIN (somatropin) for injection - prescribing information- DailyMed, National Library of Medicinelabel
- 3.HUMATROPE (somatropin) for injection - prescribing information- DailyMed, National Library of Medicinelabel
- 4.NORDITROPIN (somatropin) injection - prescribing information- DailyMed, National Library of Medicinelabel
- 5.OMNITROPE (somatropin) injection - prescribing information- DailyMed, National Library of Medicinelabel
- 6.ZOMACTON (somatropin) for injection - prescribing information- DailyMed, National Library of Medicinelabel
- 7.SEROSTIM (somatropin) for injection - prescribing information- DailyMed, National Library of Medicinelabel