RESEARCH MONOGRAPH · KDC-MN-086

hGH Fragment 176-191

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 2 min read

Our opinion on this compound

45/100

The unmodified parent fragment, similar evidence problems to AOD-9604 with even fewer clinical breadcrumbs

hGH Fragment 176-191 is the parent C-terminal sequence from which AOD-9604 was derived (AOD-9604 just adds an N-terminal tyrosine for stability). Originally identified by the Bowers and the Australian groups in the 90s during the systematic GH fragment characterization period, the rationale was the same as AOD-9604: selective lipolysis without the IGF-1 and diabetogenic effects of full-length hGH.

What we like, narrowly: the preclinical mouse work on selective hormone-sensitive lipase activation in adipocytes was a genuinely interesting moment in GH structure-activity biology. The fragment binds to a putative C-terminal hGH receptor or signaling complex (the molecular target is still not fully characterized, which is itself part of the problem) and produces lipolysis in isolated adipocyte preparations without the glucose-handling effects of full hGH.

What we dont like: the human translation story is even weaker than AOD-9604. The unmodified fragment has poor serum stability without the N-terminal tyrosine modification, so the in vivo half-life is short and the pharmacokinetics are worse. The compound never went through serious human clinical trials in its unmodified form because the developers pivoted to AOD-9604 once they had stability data showing the modification was necessary for any reasonable serum exposure.

So what you have here is essentially a research tool for studying the C-terminal fragment hypothesis of hGH lipolysis, without the modifications that would make it pharmacologically practical. For mechanism work in cell culture this is fine. For anything resembling a real lipolytic intervention it's worse than AOD-9604, which itself didn't pan out clinically.

Sourcing is straightforward for the 16-amino-acid peptide. Reputable peptide vendors produce HPLC pure material reliably, and the lack of modifications means the synthesis is simpler than AOD-9604. Stability is the limiting issue and you need to handle and store it carefully.

Honestly, this is one where we'd point researchers toward better-characterized GH-axis tools (sermorelin, tesamorelin, GHRP-2) rather than pursue the C-terminal fragment story at this point. The evidence base just hasn't developed the way the original hypothesis suggested it would.

Evidence: 25
Mechanism: 45
Reliability: 35
Safety: 78
Sourcing: 75
Value: 45
Signal: 32
Staying power: 28

Plain-language summary Intrigue 50 / 100

HGH Fragment 176-191 is the natural C-terminal fragment of human growth hormone (the parent peptide of AOD-9604). It is hypothesized to drive selective fat loss without affecting blood sugar or causing the systemic effects of full growth hormone. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

C-terminal hGH fragment

The unmodified C-terminal fragment of hGH (residues 176-191) sold as a research chemical for lipolytic applications.

Abstract

hGH Fragment 176-191 is the unmodified C-terminal 16-residue sequence of human growth hormone (Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe with a disulfide bond). The compound is a precursor to AOD-9604 (which adds a tyrosine N-terminal extension) and is sold as a research chemical with similar lipolytic claims. The mechanistic and clinical evidence base is essentially the same as for AOD-9604. The compound is not approved by any regulatory authority. Reported research dose ranges in the literature are 250 to 500 micrograms subcutaneously.

Mechanism of action

Same as AOD-9604; lipolytic effects without IGF-1 elevation.

Reported research dose ranges

250 to 500 micrograms SC (reported research dose ranges in the literature).

References

Heffernan M, et al. As above for AOD-9604.

Read the full monograph

The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, reported research dose ranges, sourcing and quality verification, reconstitution and handling, stack interaction considerations, and a curated reference list. Available as a research-use-only PDF download.

KDC-MN-086

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

Kodiac sells research compounds for investigative use only.

hGH Fragment 176-191

Abstract

Mechanism of action

Reported research dose ranges

References

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Abstract

Mechanism of action

Reported research dose ranges

References

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