# HGH Fragment 176-191

> 16-residue C-terminal fragment of human growth hormone

All products are sold strictly for laboratory research use only. Not for human or veterinary use.

- Web page: https://peptidemedixeu.com/en/products/hgh-fragment-176-191/
- Brand: Peptide Medix EU
- Category: [Fat-Loss & Metabolic Peptides](https://peptidemedixeu.com/en/collections/fat-loss-peptides/)
- Purity: ≥99% by HPLC; lot-matched COA available
- CAS number: 66004-57-7
- from €55 (EUR)

## Sizes and prices (EUR)

| Size | Price | SKU |
| --- | --- | --- |
| 5 mg | €55 | HGH-FRAGMENT-176-191-5-MG |
| 10 mg | €97 | HGH-FRAGMENT-176-191-10-MG |

_Catalog prices at build time; the web page and checkout are authoritative._

## Specifications

- **CAS number:** 66004-57-7
- **Molecular formula:** C78H125N23O23S2
- **Molecular weight:** 1817.12 g/mol
- **Amino acid sequence:** Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe
- **Chain length:** 16 amino acids, hGH numbering 176-191
- **Peptide class:** Growth hormone C-terminal fragment
- **Form:** Lyophilized powder, sealed glass vial with flip-off seal
- **Purity:** ≥99% by HPLC; lot-matched COA available
- **Available sizes:** 5 mg, 10 mg
- **Solubility:** Bacteriostatic water; sterile water also reported
- **Storage (lyophilized):** −20 °C, sealed and protected from light and moisture
- **Storage (reconstituted):** 2–8 °C, protected from light; use within the study window
- **Research areas:** Adipocyte lipolysis, lipogenesis, growth hormone structure-function studies

## Description

HGH Fragment 176-191 is a synthetic 16-amino-acid peptide reproducing the C-terminal end of human growth hormone, named after its position within the parent molecule. Structure–function research on growth hormone in the 1980s and 1990s suggested that the hormone's fat-mobilising activity resides in this region, whereas the domains required for receptor dimerisation and IGF-1 induction lie elsewhere. The isolated fragment allowed researchers to put that separation to a direct test.

It is the unmodified precursor of AOD-9604, which carries an extra N-terminal tyrosine and a stabilising disulfide bridge. As the two differ in whether they are cyclised, labs often test them side by side to see how conformation affects potency and stability. Reported uses focus on adipocyte lipolysis and lipogenesis assays, studies of fat depots in rodents and structure–activity work on growth hormone fragments in general.

## Frequently asked questions

### How does this differ from AOD-9604?

AOD-9604 is the same C-terminal stretch with an extra N-terminal tyrosine plus a Cys7-Cys15 disulfide that holds it in a ring. The plain fragment is linear, which shows up in a different molecular formula and chromatographic behaviour.

### Which purity data and documents come with it?

Each lot is HPLC-tested to ≥99% purity with mass spectrometry confirming identity, and its certificate of analysis is available. The COA refers to the vial number you receive, so the data are traceable to that exact material.

### Why is it named with residue numbers?

The numbers mark positions 176 to 191 of the 191-amino-acid human growth hormone chain. Naming it by these coordinates shows precisely which part of the hormone the peptide reproduces.

### Do the cysteines call for special care?

Yes. Its two cysteines can oxidise or pair incorrectly in solution, so minimise air exposure, avoid buffers containing free thiols and keep reconstituted peptide cold and in the dark. Verifying identity by mass spectrometry before a long study is sensible.

### What are the storage conditions?

Unopened lyophilised vials: −20 °C, protected from light and humidity. Once reconstituted: refrigerate at 2–8 °C in the dark and use within your documented study period, splitting it into single-use aliquots so it is never frozen and thawed repeatedly.

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All products offered on this website are intended solely for in-vitro laboratory research and development by qualified professionals. They are not drugs, foods, cosmetics or dietary supplements, and are not intended to diagnose, treat, cure or prevent any disease. Products must not be introduced into humans or animals in any manner. By purchasing, you confirm that you are a qualified researcher and accept full responsibility for handling and storage in accordance with applicable laws.

Peptide Medix EU · https://peptidemedixeu.com/en/products/hgh-fragment-176-191/