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What it is
Recombinant human growth hormone with the 191-amino-acid sequence identical to the endogenous hormone. The '191AA' designation distinguishes it from older 192-amino-acid methionyl variants, and is a manufacturing descriptor rather than a mark of quality.
How it is proposed to work
Direct growth hormone receptor agonism, plus indirect action through hepatic IGF-1. Unlike secretagogues it bypasses the pituitary entirely, so it is not subject to normal feedback — which is exactly why it produces effects, and adverse effects, that secretagogues do not.
Approved medical uses
Growth hormone deficiency in children and adults, and several defined syndromes and wasting states. Explicitly not approved for anti-ageing, athletic performance, bodybuilding or general body composition.
Human research
Each entry states what the study found and, separately, what it cannot show.
- Systematic review2007
Systematic review of growth hormone in the healthy elderly
Finding. Pooled the randomised literature in healthy older adults and concluded growth hormone cannot be recommended as an anti-ageing therapy. Lean body mass rose without a corresponding gain in strength, and adverse effects — oedema, arthralgia and carpal tunnel symptoms — were substantially more common than on placebo.
Limitation. This is the direct answer to the question the grey market asks, and it was answered nearly two decades ago. Figures are deliberately described rather than quoted: see the change history for why.
Preclinical research
Animal and laboratory work. Useful for generating hypotheses; it cannot establish that something works in people.
No preclinical studies catalogued.
Potential safety concerns
- SeriousEstablished
Oedema and arthralgia are common rather than rare in healthy adults — roughly 44% versus 1% on placebo in pooled trial data. This is not a minor tolerability note.
- SeriousEstablished
Insulin resistance and impaired glucose tolerance follow directly from the mechanism, and can progress to overt diabetes with sustained supraphysiological exposure.
- SeriousEstablished
Sustained excess produces acromegalic changes — soft tissue and bony overgrowth, carpal tunnel syndrome — some of which do not reverse on stopping.
- SeriousEstablished
Counterfeit and underdosed product is widespread in the grey market. Because the compound is expensive and the effects are slow, substitution is easy to conceal.
- SeriousEstablished
Legal exposure is unusual for this compound. In the US, distributing or holding hGH with intent to distribute for a non-approved use is a specific federal criminal offence — a statute that exists for no other compound in this library.
Known interactions and contraindication considerations
- Glucocorticoids interact in both directions; dose review is required.
- Affects glucose handling, so diabetes therapy needs adjustment by a prescriber.
- Contraindication considerations exist around active malignancy and acute critical illness.
This list is not exhaustive and is not a substitute for a clinician reviewing your full medication history.
Regulatory status
Status is shown per jurisdiction and is accurate only as of the date stated. Where a compound is approved, the approval is bound to a specific formulation, manufacturer and indication — shown in the detail column.
| Jurisdiction | Standing | Detail |
|---|---|---|
United States FDA | Approved as of 6 Aug 2026 |
Approved for defined deficiency and wasting indications only. Distribution, or possession with intent to distribute, for anti-ageing or athletic performance is a specific federal offence under 21 U.S.C. 333(e). Note this reaches distribution — not simple possession — and hGH is NOT a scheduled controlled substance. |
European Union EMA | Approved as of 6 Aug 2026 | Approved for comparable deficiency indications. Prescription-only. |
India CDSCO | Approved as of 6 Aug 2026 | Prescription-only for approved indications. Counterfeit supply is a documented problem in this category. |
How it is being used
What the grey community actually runs, the reasoning they give, and our read on whether it follows from known biology. This is observation, not evidence, and not a recommendation.
No community use documented for this compound yet. Absence here means our editorial team has not reviewed and verified a pattern — not that none exists.
Active clinical trials
No registered trials currently tracked for HGH 191AA.
What remains unknown
The questions that would change our assessment if they were answered.
- Is there any healthy population in which the lean-mass gain produces functional benefit? Two decades of work say no.
- Are the metabolic effects fully reversible after prolonged supraphysiological use?
References
Editorial change history
When we change a grade or a regulatory note, we log it here rather than editing quietly.
Merged two study entries into one. This dossier described a 2007 systematic review AND a separate 2008 meta-analysis of 27 trials in 440 participants. Citation resolution could not find that second paper — the figures appear to belong to the 2007 review, which is real and now cited. An invented second source is exactly the failure this platform exists to call out, so it is recorded rather than quietly deleted. Remaining figures are described qualitatively until read from the full text.
Dossier created and graded Tested, no benefit for its grey-market use. Fact-check corrections applied: hGH is NOT a scheduled controlled substance, and 21 U.S.C. 333(e) reaches distribution and possession with intent to distribute, not simple possession. Both errors are common in secondary sources and neither was published.
Spotted something wrong? Tell us — we publish corrections.