HGH Fragment 176-191

What is HGH Fragment 176-191?

HGH Fragment 176-191 is a synthetic 16-amino-acid peptide that reproduces residues 176 to 191 at the C-terminus of the 191-amino-acid human growth hormone molecule. Its sequence is FLRIVQCRSVEGSCGF, with a disulfide bridge between the two cysteine residues forming a small loop.

The C-terminal region of growth hormone was identified in early research as the part of the molecule associated with its effects on lipid metabolism, separate from the growth-promoting activity that depends on the full protein and its induction of IGF-1. HGH Fragment 176-191 is the unmodified native sequence; a closely related analogue, AOD-9604, adds an N-terminal tyrosine and has been studied in clinical trials, whereas the native fragment itself has not.

GenoPept supplies HGH Fragment 176-191 to UK laboratories in 2mg, 5mg and 10mg lyophilised vials, each batch verified at ≥99% purity with a third-party Certificate of Analysis.

HGH Fragment 176-191 research applications

HGH Fragment 176-191 is investigated as a tool for separating the metabolic and growth-promoting domains of growth hormone:

• Adipocyte lipid metabolism – the fragment has been studied in isolated adipocyte and animal models for effects on lipolysis and lipogenesis, the area of interest that first defined the C-terminal region.
• Growth hormone structure–function research – it is used to map which parts of the GH molecule are responsible for which activities, including receptor-independent effects.
• Metabolic and obesity models – animal studies in the compound class have investigated C-terminal GH fragments in diet-induced obesity and glucose handling.
• Comparative fragment studies – the native fragment is the reference for modified analogues such as AOD-9604, allowing the effect of the Tyr substitution to be assessed.
• Cartilage and connective tissue – some preclinical work has examined GH C-terminal peptides in chondrocyte models.

Published clinical data relate to the modified analogue rather than to HGH Fragment 176-191 itself, and this distinction matters when reading the literature.

Mechanism of action (preclinical)

HGH Fragment 176-191 does not bind the growth hormone receptor in the way the full hormone does and, in preclinical models, does not raise IGF-1 or affect glucose uptake through the insulin pathway. The proposed mechanism involves modulation of adipocyte enzyme activity, with animal studies in the compound class reporting increased hormone-sensitive lipase activity and reduced fatty acid synthase expression.

Research also points to a beta-3 adrenergic receptor-associated pathway in adipose tissue as a contributor to the reported effects of C-terminal GH fragments, though the full mechanism remains under investigation.

HGH Fragment 176-191 product specifications

Each vial is supplied to the specification below. Rows are limited to values that can be verified from published sources.

Available sizes

• HGH Fragment 176-191 2mg vial, lyophilised powder
• HGH Fragment 176-191 5mg vial, lyophilised powder
• HGH Fragment 176-191 10mg vial, lyophilised powder

Bulk and wholesale boxes of 10 vials of HGH Fragment 176-191 save 20–50% for laboratories running larger studies; see the bulk and wholesale page. Free UK delivery applies to orders of £200 or more.

Reconstitution, handling and storage (laboratory)

HGH Fragment 176-191 is shipped as a lyophilised powder and should be stored unopened at –20 °C for long-term laboratory storage, or at 2–8 °C for short periods, protected from light. Allow the sealed vial to reach room temperature before opening to avoid condensation on the powder.

To reconstitute, add bacteriostatic water or another sterile diluent slowly down the inside wall of the vial, then swirl gently until dissolved. Never shake, as shear stress can denature the peptide. The peptide contains a disulfide bridge, so avoid reducing agents in the diluent. After reconstitution keep the solution at 2–8 °C and use it within the period defined in your laboratory protocol.

Full step-by-step guidance is available in our articles on how to reconstitute research peptides and how to store research peptides. Handle with gloves and standard laboratory precautions.

Quality assurance and Certificate of Analysis

Every batch of HGH Fragment 176-191 is tested by an independent third-party laboratory (Puralytix, ISO/IEC 17025 accredited). Purity is confirmed by HPLC at ≥99% and identity is confirmed by LC-MS, so the material in the vial matches the label.

A batch-specific Certificate of Analysis is available through the “View Certificate of Analysis” button on this page, and the complete library is published in the COA library. Our guide to what a Certificate of Analysis shows explains how to read the chromatogram and mass spectrum. Vials are batch-identified with lot number and expiry, and orders are dispatched discreetly by tracked Royal Mail Special Delivery within the UK.

Related research compounds

• AOD-9604 – the Tyr-modified analogue of HGH Fragment 176-191 with published clinical literature
• Somatropin HGH 191-AA Research Kits – the full-length recombinant growth hormone from which the fragment is derived
• 5-Amino-1MQ – an NNMT inhibitor studied in adipocyte metabolism models
• MOTS-c – a mitochondrial peptide studied in metabolic regulation research

HGH Fragment 176-191 frequently asked questions

What is HGH Fragment 176-191 used for in research?

HGH Fragment 176-191 is used in laboratory studies of the C-terminal domain of growth hormone. Researchers apply it in adipocyte lipid metabolism assays, growth hormone structure–function mapping, animal models of obesity and glucose handling and comparative studies with the modified analogue AOD-9604. Supplied for in-vitro laboratory research only.

How is HGH Fragment 176-191 supplied and what is its purity?

GenoPept supplies HGH Fragment 176-191 as lyophilised powder in sealed, sterile glass vials of 2mg, 5mg or 10mg with a black cap and batch label. Every lot is tested by an independent ISO/IEC 17025 laboratory, with ≥99% purity by HPLC and identity confirmed by LC-MS. The batch Certificate of Analysis is available on the product page.

How should HGH Fragment 176-191 be stored?

Keep unopened HGH Fragment 176-191 vials at –20 °C for long-term storage or 2–8 °C short term, protected from light. After reconstitution with bacteriostatic water, store the solution at 2–8 °C, avoid freeze–thaw cycles and use within the period specified by your laboratory protocol.

Is HGH Fragment 176-191 for human use?

No. HGH Fragment 176-191 is supplied only for in-vitro laboratory research. It is not a medicine, has never been approved for human or veterinary use and is not for diagnostic or therapeutic purposes. UK customers must agree to the research use only policy before ordering.

What is the difference between HGH Fragment 176-191 and AOD-9604?

HGH Fragment 176-191 is the native 16-amino-acid C-terminal sequence of growth hormone, while AOD-9604 is the same sequence with a tyrosine added at the N-terminus, giving 17 residues in total and slightly higher molecular weight. AOD-9604 was developed as an investigational compound and has clinical literature; the native fragment has been studied only in preclinical and cell-based models.

Research use only. This product is supplied strictly for in-vitro laboratory research. It is not for human or veterinary use, not a medicine, and not for diagnostic or therapeutic use. Read the GenoPept research use only policy before ordering.