HGH Fragment 176-191
updated
HGH Fragment 176-191 is the unmodified 16-amino-acid tail end of human growth hormone, sold for fat loss without growth hormone's other effects. Rodent studies reported changes in fat metabolism and less weight gain without the growth effects of intact growth hormone, but no study has given this exact fragment to people. AOD9604, a modified cousin with an added tyrosine, is a different peptide, and its failed phase 2b obesity trials cannot stand in for it. Graded C for direct animal metabolism research with no human study of the exact fragment.
unmodified C-terminal human growth-hormone fragment
- Sequence FLRIVQCRSVEGSCGF
- Corresponds to hGH residues 176-191
- Different from Tyr-hGH177-191, known as AOD9604
- No cited direct human trial
Is HGH Fragment 176-191 the same as AOD9604?
HGH Fragment 176-191 is unmodified FLRIVQCRSVEGSCGF. AOD9604 adds an N-terminal tyrosine and is a different peptide. That change can affect stability, exposure, and biological activity.
| Name | Sequence definition | Human evidence |
|---|---|---|
| HGH Fragment 176-191 | Unmodified hGH residues 176-191 | No cited direct administered-human study |
| AOD9604 | Tyr-hGH177-191 | Separate human development program; its efficacy result does not apply to hGH176-191 |
source: AOD9604 · related modified molecule, Heffernan MA et al. International Journal of Obesity, 2001.
Does HGH Fragment 176-191 cause fat loss in people?
The cited evidence includes no direct human efficacy result for exact unmodified hGH176-191. Positive mouse fat-metabolism results and AOD9604's separate human program do not establish human weight loss for this molecule.
Can the AOD9604 trials answer this?
Those trials tested a modified peptide, so their results apply to AOD9604 rather than unmodified hGH176-191.
source: PubMed and registry · no direct human trial, PubMed and ClinicalTrials.gov records for hGH176-191 and exact aliases.
source: Mouse study · fat loss without growth effect, Ng FM et al. Endocrinology, 2000.
What did the fragment do in animals?
Rodent studies reported changes in fat metabolism, weight gain, and adipose mass without the growth effects of intact growth hormone. The magnitude, exposure, and metabolic context do not supply a human dose or expected outcome.
The rodent studies measured C-terminal effects on fat metabolism. They did not test muscle retention, durable weight loss, or cardiovascular benefit in people.
source: Mouse study · fat loss without growth effect
source: Mouse metabolism · lipolytic hypothesis, Heffernan MA et al. Endocrinology, 2001.
What is known about HGH Fragment 176-191 side effects and human safety?
The cited evidence provides no direct human pharmacokinetic or safety data for exact unmodified hGH176-191. Immune reactions, glucose effects, repeated exposure, pregnancy, interactions, and the safety of injected market products remain unknown.
- Sequence identity: AOD9604 and hGH176-191 should not share a safety profile by assumption.
- Disulfide chemistry: the two cysteines make oxidation, folding, and aggregation product-specific issues.
- Injection quality: sterility, endotoxin, potency, and degradation are separate from peptide mechanism.
Is HGH Fragment 176-191 FDA approved?
The cited FDA records list no approved HGH Fragment 176-191 product or dosing label. WADA prohibits growth-hormone fragments for covered athletes.
source: PubMed and registry · no direct human trial
source: WADA 2026 · GH fragments, World Anti-Doping Agency, effective 1 January 2026.
What doses have human studies used?
These are doses that cited human studies or FDA labels used, in the people they studied; none is a recommendation or a protocol. No published human study on file reports a dose for this compound.
Studies and sources
Mouse study · fat loss without growth effect
Animal study
Ng FM et al. Endocrinology, 2000.
A C-terminal growth-hormone fragment reduced weight gain and adipose-tissue mass in obese mice without reproducing the growth-promoting activity of intact growth hormone. The experiment did not test human body composition, appetite, or safety.
- Participants / model
- Genetically obese and normal mice
- Treatment
- C-terminal hGH fragment
- Study design
- Controlled animal metabolic study
Mouse metabolism · lipolytic hypothesis
Animal study
Heffernan MA et al. Endocrinology, 2001.
The study reported fat-metabolism effects of a C-terminal growth-hormone fragment in mice and supported a lipolytic mechanism distinct from full-length growth hormone. It did not establish human exposure or outcomes.
- Participants / model
- Mice in metabolic experiments
- Treatment
- C-terminal hGH fragment
- Study design
- Controlled animal study
AOD9604 · related modified molecule
Animal and mechanistic study
Heffernan MA et al. International Journal of Obesity, 2001.
The paper studied Tyr-hGH177-191, later called AOD9604. Its added N-terminal tyrosine makes it a different molecule from unmodified hGH176-191.
- Participants / model
- Rodent metabolic models
- Treatment
- Tyr-hGH177-191
- Study design
- Preclinical obesity study
AOD9604 adds an N-terminal tyrosine, so its clinical results do not apply to unmodified hGH176-191.
Read the original sourcePubMed and registry · no direct human trial
PubMed and ClinicalTrials.gov records
PubMed and ClinicalTrials.gov records for hGH176-191 and exact aliases.
The cited records include no administered-human study of unmodified hGH176-191 or relevant registered intervention. AOD9604 and full-length growth hormone are different interventions.
Read the original sourceWADA 2026 · GH fragments
Sports rule
World Anti-Doping Agency, effective 1 January 2026.
Growth hormone, its fragments, and releasing factors are prohibited under S2 for athletes covered by the Code.
- Study design
- Binding sport rule for covered athletes
Why is HGH Fragment 176-191 in C tier?
The C grade reflects direct animal metabolism research and no administered-human study of the exact unmodified fragment. AOD9604 is a different peptide, and its trials do not establish human fat loss, injection safety, or a regimen for hGH176-191.
how tiers are graded: methodology · every cited source · about reptides.
Research reference, not medical advice. Entries distinguish product labels, study doses and reported protocols. Check the linked source for the product, route and population.