GH-Derived Peptide Fragment Class / hGH C-Terminal Research Compounds
hGH C-Terminal Fragment Research — AOD-9604 & HGH Fragment 176-191
AOD-9604 and HGH Fragment 176-191 are two closely related growth-hormone-derived peptides studied in adipocyte and metabolic-biochemistry models. Both are truncated C-terminal fragments of human growth hormone (hGH) — the region associated with hGH's lipolytic activity in cell culture, distinct from the N-terminal domain that mediates IGF-1 secretion and anabolic signaling. AOD-9604 (CAS 221231-10-3; MW ~2036 Da) is a stabilized fragment comprising hGH residues 177–191 with a Tyr modification at the N-terminus. HGH Fragment 176-191 (CAS 66004-57-7; MW ~1815 Da) refers to residues 176–191 of hGH. Both appear in adipogenesis and lipolysis literature. This hub covers both compounds, their structural differences, and their research contexts. Research use only.
Compound identity
- Name
- hGH C-Terminal Fragments — AOD-9604 & HGH Fragment 176-191 Research Hub
- Class
- GH-Derived Peptide Fragment Class / hGH C-Terminal Research Compounds
- Also known as
- AOD-9604 research, HGH fragment 176-191 research, AOD 9604 vs HGH fragment, hGH C-terminal fragment, growth hormone fragment peptide, AOD-9604 HGH fragment comparison, adipocyte research peptide, hGH 177-191, AOD9604
Research context
The mechanistic rationale for studying hGH C-terminal fragments originates from structure-activity work on growth hormone in the 1980s–1990s: the C-terminal region of hGH (approximately residues 176–191) was observed to stimulate lipolysis in cultured adipocytes at concentrations far lower than those required for the full-length hormone, and without measurable IGF-1 stimulation. That separation of activities is what made the fragment an interesting research probe — it isolates one biochemical readout from the anabolic and glycemic signaling of the full-length hormone. AOD-9604 was synthesized by Metabolic Pharmaceuticals (Australia), which added a tyrosine residue at the N-terminus for improved stability. HGH Fragment 176-191 is the corresponding unmodified natural-sequence fragment and is the form more commonly referenced in academic literature.
AOD-9604 has the longer development record of the two, having progressed through clinical evaluation before development was discontinued; it holds no regulatory approval for any indication, in any jurisdiction. In-vitro studies with both AOD-9604 and HGH Fragment 176-191 have examined adipocyte lipolysis rates and, separately, chondrocyte function and bone/cartilage metabolism — a line of investigation that emerged from the AOD-9604 program and that makes these compounds of interest beyond adipocyte models.
For researchers comparing AOD-9604 and HGH Fragment 176-191: the primary distinction is the N-terminal Tyr modification (present in AOD-9604, absent in HGH Frag 176-191), which affects the peptide's stability in aqueous solution and its binding characteristics. Functionally, both compounds engage the same putative receptor region and produce similar lipolytic readouts in adipocyte culture. AOD-9604 carries the richer published dataset; HGH Fragment 176-191 is more commonly cited in mechanistic biochemistry papers. Neither compound is approved for any therapeutic use. Both are supplied as research-grade lyophilized peptides with ≥99% purity by HPLC and a per-batch COA.
Frequently asked questions
What is the difference between AOD-9604 and HGH Fragment 176-191?+
AOD-9604 (CAS 221231-10-3, MW ~2036 Da) is hGH residues 177–191 with an additional N-terminal Tyr residue for stabilization. HGH Fragment 176-191 (CAS 66004-57-7, MW ~1815 Da) is the natural-sequence fragment of hGH residues 176–191. Both produce similar lipolytic readouts in adipocyte culture; AOD-9604 carries the larger published dataset. Research use only.
How does the hGH C-terminal fragment work mechanistically?+
The C-terminal region of human growth hormone (approximately residues 176–191) stimulates lipolysis in cultured adipocytes through a mechanism that does not require IGF-1 secretion or the anabolic signaling of full-length GH. In-vitro studies indicate increased lipase activity and free fatty acid release in the culture medium. The fragment does not appear to substantially engage the growth hormone receptor's anabolic pathway. Research use only; no approved therapeutic claim.
What is AOD-9604's research history?+
AOD-9604 was synthesized by Metabolic Pharmaceuticals (Australia) and advanced through clinical evaluation before development was discontinued. It holds no regulatory approval for any indication. Current research references the historical dataset or preclinical adipocyte and chondrocyte models. Research use only.
Are hGH fragments studied alongside other peptides?+
In published work, AOD-9604 and HGH Fragment 176-191 appear alongside other metabolic peptides including GLP-1 analogs and GHRPs in animal-model and cell-culture studies. Any such combination work is strictly in-vitro or animal-model research. These are research compounds only — not approved for human use, not for human consumption, research use only.
Research use only
All products are intended for laboratory and research use only (RUO) and are not for human consumption, ingestion, or any in-vivo use.
The statements on this page have not been evaluated by the FDA. hGH C-Terminal Fragments — AOD-9604 & HGH Fragment 176-191 Research Hub is not intended to diagnose, treat, cure, or prevent any disease. Content is provided for laboratory research reference only.