If a supplied lot fails agreed specifications, we’ll replace it at no cost or refund its purchase price in full.
Quality test failed? Free replacement or full refund.
Off-spec? Free replacement or full refund.
Reading a Peptide HPLC Trace — A 5-Minute Field Guide for Bench Scientists. Read our briefing →
Reading a peptide HPLC trace — a field guide. Read →
On reading HPLC traces. Read →
C-terminal fragment of human growth hormone (176–191)
Research documentation
HGH Fragment 176-191 is supplied for laboratory research. Contact sales to confirm the available identity, purity, and lot records, and discuss the evidence your assay or method-development project requires.
Overview
HGH Fragment 176-191 is a 16-residue peptide corresponding exactly to the C-terminal segment (residues 176-191) of the 191-amino-acid human growth hormone chain, supplied here in its native, unmodified form. Functionally it isolates the lipolytic character attributed to that terminal region while omitting the central portions of GH responsible for the hormone's wider anabolic and IGF-1-stimulating actions. This is the point of distinction from the AOD9604 analog, which carries an added N-terminal tyrosine for radioiodination tracking; because the fragment retains the unaltered native sequence, it is the form researchers reach for when studying C-terminal lipolytic activity on its own. Lyochem supplies HGH Fragment 176-191 as a lyophilized reference standard to a ≥99.0% HPLC purity specification, fully specified: CAS 66004-57-7, C78H123N23O22S2, MW 1799.1 g/mol, sequence FLRIVQCRSVEGSCGF. Note the cysteines at positions 7 and 14, which under oxidative conditions can close an intramolecular disulfide; oxidized and reduced species differ by 2 Da and resolve at separate RP-HPLC retention times, so this is the chief identity check we flag on the COA alongside ESI-MS confirmation. Six fills span 1-15 mg. Research use only.
Applications & buyer fit
GH-axis peptides ship to research labs studying somatotropic-pathway pharmacology and related models. Ask sales for the matching batch COA. Sequence, counter-ion, or stability evidence beyond that record is included only when required by a written project scope and agreed before quotation.
Academic Laboratories
Universities, medical schools, and government research institutes qualifying a reference standard for a method-development or in vivo workflow.
Biotech R&D Groups
Preclinical biotech and pharmaceutical discovery teams sourcing characterized peptides for receptor-pharmacology, screening, and method-development campaigns.
Every lot has its own batch-specific CoA — HPLC purity and MS identity, plus any analytical scope agreed at quote stage — tied to the exact lot you receive.
Review a representative batch CoA before you order, so you can confirm the packet matches what your method or sponsor audit needs.
Supplied strictly as a research reagent to research institutions — not a finished dosage form and not for human administration. Buyer qualification runs at the inquiry stage.
Specifications
Documentation available on request
Regulatory note
The two are not chemically equivalent, so prior to placing an order, verify the precise fragment identity (unmodified versus AOD9604-modified) using the batch COA. This material is readily mistaken for AOD9604, which is the modified analog carrying an N-terminal tyrosine.
Selected literature
Frequently asked questions
The two 16-residue peptides differ by a single N-terminal residue (Phe in the native fragment, Tyr in AOD9604), a mass difference of roughly 16 Da from the extra oxygen on the tyrosine side chain. That is a small delta relative to the parent mass, so if that distinction is required, the agreed ESI-MS method must have adequate resolution and calibration to distinguish the two confidently rather than report an ambiguous averaged mass. An orthogonal LC-MS/MS sequence read that pins the N-terminal residue is the safest confirmation, and RP-HPLC retention differences (the Tyr hydroxyl makes AOD9604 slightly more polar) provide a supporting check.
The fragment's two cysteines can exist as free thiols (reduced) or as an intramolecular disulfide (oxidized), and the forms differ by about 2 Da and resolve at different RP-HPLC retention times. To confirm which form a batch represents, use ESI-MS to read the 2 Da difference and RP-HPLC to match the expected retention peak; a free-thiol assay (for example Ellman's reagent) can independently confirm the reduced species. Since most published work uses the oxidized, disulfide-bridged form as the more stable solid, buyers whose protocol depends on a specific redox state should require the COA to state it explicitly.
Related peptides