Frag 176–191: Growth Hormone–Derived Fragment and Lipolytic Research Mechanisms

Q: Is Frag 176–191 considered a therapeutic compound?

No. Frag 176–191 supplied by The Peptide Company is for laboratory and in-vitro research use only. It is not a therapy, drug, supplement, or product for human or clinical use.

Q: How is Frag 176–191 typically handled in laboratory settings?

Frag 176–191 is usually supplied as a lyophilized powder, stored away from heat, moisture, and light. After reconstitution, it is kept refrigerated according to laboratory protocol.

Daniel Attalla
Nov 17, 2025
3 min read

3D molecular structure artwork of Frag 176–191 shown in The Peptide Company’s charcoal and orange research branding

Introduction

Frag 176–191 is a synthetic peptide representing the C-terminal region of the human growth hormone (GH) molecule. It does not activate the GH receptor and does not stimulate IGF-1 production. Instead, it exhibits fragment-specific behavior in adipocyte research models, particularly involving lipolytic and metabolic signaling pathways. This article examines Frag 176–191’s structural basis, receptor-independent activity, and relevance in GH-fragment research.

What Is Frag 176–191?

Frag 176–191 is a 15–amino-acid peptide derived from the lipolytic region of GH. It excludes domains required for GH receptor binding, making it useful for studying GH fragment–specific activity without engaging the GH → IGF-1 endocrine axis. It is frequently used in adipocyte and metabolic research models to explore lipid mobilization and energy regulation.

Structural Overview

Full-length human GH is 191 amino acids long. The region spanning residues 176–191 has been identified as central to GH’s lipolytic signaling. Frag 176–191 isolates this region, eliminating all GHR-binding components. Modified versions of this fragment often incorporate substitutions that increase stability and protect against rapid enzymatic degradation.

Mechanism of Action (Research Context)

Frag 176–191 is notable for its non–GH receptor-mediated behavior. It influences adipocyte metabolic pathways including cAMP accumulation, PKA activation, and downstream regulation of hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL). Studies also show interactions with AMPK signaling and mitochondrial fatty acid oxidation pathways in metabolic models.

Frag 176–191 vs Full-Length GH (Mechanistic Only)

The fragment’s short structure and absence of GH receptor binding separate its behavior from the classical GH → IGF-1 endocrine axis. While full-length GH activates JAK2/STAT5 and IGF-1 production, Frag 176–191 operates through cAMP–PKA and lipolytic enzyme regulation. This makes it a valuable tool in studies that require GH-related lipolysis without systemic anabolic signaling.

Cellular Pathways Associated With Frag 176–191

Key pathways associated with Frag 176–191 include:• cAMP → PKA activation • Regulation of HSL and ATGL • AMPK pathway involvement • β-oxidation and mitochondrial signaling • Suppression of lipogenic pathways These pathways define the fragment’s relevance in adipocyte metabolic research models.

Research Applications

Frag 176–191 is used for studying GH fragment–specific lipolysis, adipocyte metabolism, endocrine-independent GH motif signaling, lipid mobilization, and metabolic regulation circuits. It is frequently referenced alongside AOD‑9604, Tesamorelin, CJC‑1295, and GLP-1 pathway research in comparative metabolic studies.

Summary

Frag 176–191 isolates the lipolytic region of the GH protein while removing GH receptor signaling and IGF-1 axis involvement. Its receptor-independent metabolic behavior makes it suitable for studying adipocyte activity, lipid breakdown mechanisms, and GH fragment functional specificity in controlled research environments.

Frag 176–191 vs Full-Length GH (Research Comparison)

Property	Full-Length GH	Frag 176–191
Length	191 amino acids	15 amino acids
Receptor Binding	Activates GH receptor	Does not activate GH receptor
IGF-1 Axis Activation	Yes	None
Mechanism	JAK2–STAT5 endocrine pathway	cAMP–PKA, HSL/ATGL pathways
Research Use	Endocrine, metabolic, anabolic studies	Lipolysis, adipocyte-specific models

FAQ — Frag 176–191

Q1. What is Frag 176–191 in research?Frag 176–191 is a laboratory peptide fragment derived from the C-terminal region of growth hormone. It is studied for its role in experimental models of lipolysis regulation, energy utilization, and metabolic signaling pathways.

Q2. How does Frag 176–191 function in laboratory studies?In preclinical research, Frag 176–191 has been shown to influence pathways associated with fat-cell metabolism and lipid mobilization without activating traditional growth hormone–related receptors. These findings remain experimental only.

Q3. Is Frag 176–191 considered a therapeutic compound?No. Frag 176–191 provided by The Peptide Company is for laboratory and in-vitro research use only. It is not a therapy, drug, supplement, or product for human or clinical use.

Q4. What research applications involve Frag 176–191?Researchers explore Frag 176–191 in controlled studies related to lipid turnover, fat-cell signaling, metabolic pathways, and mitochondrial energy mechanisms.

Q5. Does Frag 176–191 show lipolytic activity in studies?Preclinical data suggest Frag 176–191 may influence markers of lipolysis and adipocyte activity in experimental systems. These observations apply only to controlled research environments.

Q6. How is Frag 176–191 typically handled in laboratory settings?It is supplied as a lyophilized powder and is generally stored away from heat, moisture, and light. After reconstitution, it is kept refrigerated according to laboratory protocol.

Q7. Can Frag 176–191 be administered or used by consumers?No. Frag 176–191 is not intended for self-administration or consumer use. It is exclusively for institutional lab research and in-vitro experimentation.