HGH Fragment 176-191
C-terminal fragment of human growth hormone (176–191)
Overview
HGH Fragment 176-191 is the unmodified 16-amino-acid C-terminal fragment of native human growth hormone, corresponding to residues 176-191 of the full-length 191-amino-acid HGH protein. The fragment retains the lipolytic activity associated with this region of native HGH while lacking the central regions that mediate the broader anabolic and IGF-1-stimulating effects of full-length GH. Distinct from the AOD9604 modified analog (which adds an N-terminal tyrosine for iodination-tracking purposes), HGH Fragment 176-191 is the unmodified native sequence and is the form typically used in research workflows studying the lipolytic activity of the HGH C-terminal region in isolation from the rest of the molecule. Lyochem supplies HGH Fragment 176-191 at ≥99.0% HPLC purity with full identification: CAS 66004-57-7, formula C78H123N23O22S2, MW 1817.1 g/mol, sequence YLRIVQCRSVEGSCGF (note the two cysteines at positions 7 and 13 that can form an intramolecular disulfide bridge under oxidative conditions). The disulfide-bridging behavior is the most common identity-confirmation concern, the reduced and oxidized forms differ by 2 Da and elute at different RP-HPLC retention times. Six standard fill sizes (1-15 mg) cover most research and compounding workflows.
Who buys this, and why
GH-axis peptides ship to research labs studying somatotropic-pathway pharmacology, IGF-axis signalling, and pulse vs. sustained-elevation GH biology. Buyers qualifying a new source typically request sequence verification on the first lot, the counter-ion form (acetate by default), and stability data at −20 °C. Blends — the CJC-1295 + Ipamorelin co-formulated lot is the canonical example — are co-lyophilised rather than solution-mixed so the ratio is locked at the lyophilisation step.
Primary buyer fit: academic and contract research laboratories and research laboratories that have validated this peptide into their workflow.
Specifications
- CAS
- 66004-57-7
- Molecular Formula
- C78H123N23O22S2
- Molecular Weight
- 1817.1 g/mol
- Sequence
- YLRIVQCRSVEGSCGF
- Appearance
- White lyophilized powder
- Purity (HPLC)
- ≥ 99.0%
- Common vial sizes
- 1 mg, 2 mg, 5 mg, 10 mg, 12 mg, 15 mg
- MOQ
- On request
- Lead time
- 10–18 days
- Storage
- -20°C, protect from light
Documentation available on request
- Lot-specific Certificate of Analysis (CoA)
- RP-HPLC chromatogram with peak integration
- ESI-MS identity confirmation (±0.5 Da)
- Sequence verification by LC-MS/MS
- Water content by Karl Fischer
- SDS / MSDS
- Counter-ion analysis (acetate vs TFA)
- Stability at −20 °C across 12 months
- Solubility in BAC water / PBS reconstitution
Regulatory note
Easily confused with AOD9604 (the modified analog with N-terminal tyrosine). Confirm exact fragment identity (unmodified vs. AOD9604-modified) via batch COA before order placement; the two are not chemically equivalent.
Frequently asked questions
How do I distinguish HGH Fragment 176-191 from AOD9604 at the analytical level?▾
The two molecules differ by a single N-terminal tyrosine residue: AOD9604 adds Tyr to the N-terminus of the native 176-191 sequence, producing a 17-amino-acid molecule with theoretical MW ≈1980 Da, while HGH Fragment 176-191 is the unmodified 16-amino-acid sequence at theoretical MW 1817.1 Da. The +163 Da mass difference is the diagnostic mass-spec check at first-time supplier qualification. RP-HPLC retention time is also slightly different, the more hydrophobic AOD9604 (with the Tyr) elutes slightly later under typical conditions. Buyers should always confirm the released-batch mass against the expected mass for the form they ordered, since the molecules are easy to confuse but biologically distinct.
What does the intramolecular disulfide bond in HGH Fragment 176-191 mean for handling?▾
The 176-191 sequence (YLRIVQCRSVEGSCGF) contains two cysteines (positions 7 and 13 within the fragment) that can form an intramolecular disulfide bond. Under reducing conditions during synthesis, the cysteines are free thiols; under oxidative conditions during storage and reconstitution, they can form the disulfide bridge. The reduced and oxidized forms differ by 2 Da in mass and elute at different RP-HPLC retention times. Most published research uses the oxidized (disulfide-bridged) form, which is the more stable solid-state form. Buyers should confirm with the COA which form the batch represents, if your research protocol requires a specific form, this matters operationally.
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