HGH 191AA For Lab Research

HGH 191AA | Buy Human Growth Hormone 191AA UK | Recombinant hGH Research Peptide | Research Use Only

HGH 191AA — recombinant human growth hormone comprising the full 191-amino acid sequence of endogenous somatotropin — is the complete, bioidentical form of GH used as the gold-standard reference compound in growth hormone axis research, somatotroph biology, and IGF-1 pathway studies. Available to buy in the UK from Peptides Lab UK at >99% HPLC-verified purity, HGH 191AA is the benchmark GH compound against which all GH secretagogues, GHRH analogues, and GH fragment peptides are compared in pre-clinical research.

Distributed by Peptides Lab UK in lyophilised format for laboratory and in vitro research use only. Each batch undergoes rigorous independent quality analysis to ensure >99% purity (HPLC and mass spectrometry verified). Not intended for human or veterinary use.

What Is HGH 191AA?

HGH 191AA is recombinant human growth hormone — a 191-amino acid single-chain polypeptide produced via recombinant DNA technology to replicate the complete sequence and three-dimensional structure of endogenous human somatotropin. The designation ‘191AA’ refers to the full 191-amino acid chain length of the mature human GH molecule, distinguishing it from truncated GH fragments, modified analogues, and the 192-amino acid methionyl-GH (met-GH) form produced by early bacterial expression systems.

Endogenous human growth hormone is secreted in pulsatile bursts by somatotroph cells in the anterior pituitary gland in response to hypothalamic GHRH stimulation. It exerts its effects through two primary pathways: direct binding to the GH receptor (GHR) on target tissues — producing immediate metabolic effects including lipolysis, insulin antagonism, and protein synthesis — and indirect stimulation of IGF-1 production in the liver and peripheral tissues, which mediates the majority of GH’s anabolic and growth-promoting effects.

As a research compound, HGH 191AA provides the complete GH pharmacological profile — including GHR binding, JAK2/STAT5 signalling, IGF-1 axis stimulation, lipolysis, nitrogen retention, and carbohydrate metabolism effects — making it the essential reference standard for the full range of GH axis research applications and the benchmark against which all partial or modified GH compounds are characterised.

Important note for the research community: HGH 191AA is the bioidentical 191-amino acid sequence and should be distinguished from met-GH (192AA, containing an additional N-terminal methionine from bacterial expression), as well as from GH secretagogues such as CJC-1295 and Ipamorelin, which stimulate endogenous GH release rather than providing exogenous GH directly.

How Does HGH 191AA Work?

GH Receptor Binding and JAK2/STAT5 Signalling

HGH 191AA exerts its primary biological effects by binding to the growth hormone receptor (GHR) — a single-pass transmembrane receptor belonging to the cytokine receptor superfamily — on target cells in the liver, adipose tissue, muscle, bone, and other peripheral organs. GHR binding induces receptor dimerisation and activation of the associated Janus kinase 2 (JAK2), triggering a phosphorylation cascade that activates Signal Transducer and Activator of Transcription 5 (STAT5) — the primary transcriptional mediator of GH’s genomic effects, including IGF-1 gene expression.

IGF-1 Axis Stimulation

One of the most studied effects of HGH 191AA in research models is its stimulation of insulin-like growth factor 1 (IGF-1) production, primarily in hepatocytes. Hepatic IGF-1 is released into circulation and acts on IGF-1 receptors throughout the body to mediate GH’s anabolic effects — including protein synthesis, cell proliferation, linear bone growth, and lean tissue accretion. The GH/IGF-1 axis is one of the most extensively studied endocrine systems in pre-clinical research, and HGH 191AA is the primary tool for studying its regulation.

Direct Metabolic Effects — Lipolysis and Insulin Antagonism

Beyond IGF-1-mediated anabolic effects, HGH 191AA exerts direct metabolic actions via GHR signalling: stimulating lipolysis in adipose tissue (increasing free fatty acid mobilisation), promoting nitrogen retention and protein synthesis in muscle, and antagonising insulin signalling — producing a relative insulin resistance in peripheral tissues that directs metabolic substrate use towards fat oxidation and spares carbohydrate for glucose-dependent tissues. These direct GHR-mediated metabolic effects are studied separately from the IGF-1-mediated anabolic axis using selective pathway inhibitors and GHR knockout models.

Pulsatile Secretion and GH Axis Dynamics

Endogenous GH is released in discrete pulsatile bursts governed by the interplay between hypothalamic GHRH (stimulatory) and somatostatin (inhibitory). In research models, HGH 191AA is used to study GHR signalling downstream of these pulses — including receptor desensitisation, GH binding protein (GHBP) dynamics, and the metabolic consequences of pulsatile vs continuous GH exposure — providing a complete picture of GH axis biology that cannot be replicated with secretagogues or fragments alone.

GH Isoforms and the 191AA Research Standard

Endogenous GH circulates as a mixture of isoforms, with the 22 kDa, 191-amino acid monomer accounting for the majority of circulating GH. HGH 191AA produced by recombinant expression replicates this predominant isoform, providing a pharmacologically defined, sequence-confirmed research standard that removes the isoform variability inherent in biological GH preparations — making it the preferred form for controlled in vitro and pre-clinical studies.

What Does HGH 191AA Do in Research?

In laboratory and pre-clinical settings, HGH 191AA has been studied across the full breadth of growth hormone biology research, including:

• GH receptor (GHR) binding kinetics, dimerisation, and JAK2/STAT5 signalling pathway characterisation
• IGF-1 axis regulation — hepatic IGF-1 production, circulating IGF-1 levels, and IGF-1R-mediated anabolic signalling
• Somatotroph biology and pituitary GH secretion regulation — feedback, receptor desensitisation, and pulse dynamics
• GH-mediated lipolysis and adipose tissue metabolism — comparison with GH fragment and secretagogue activity
• Protein synthesis, nitrogen retention, and lean mass accretion in skeletal muscle models
• Bone growth and linear growth axis research — GH/IGF-1-mediated chondrocyte and osteoblast biology
• GH-induced insulin resistance and glucose homeostasis — metabolic substrate switching mechanisms
• GH binding protein (GHBP) dynamics and circulating GH half-life modulation
• GH deficiency models and GH replacement biology — somatopause, pituitary insufficiency, and childhood GHD
• GH axis ageing research — decline of GH pulse amplitude and IGF-1 levels with age
• Reference standard for GH secretagogue benchmarking — CJC-1295, Ipamorelin, GHRP-2, GHRP-6, Sermorelin
• GH and cancer biology — IGF-1 axis and cellular proliferation research
• HIV/AIDS wasting and cachexia pre-clinical models
• Wound healing, collagen synthesis, and tissue repair research
• Comparative GH isoform pharmacology — 22 kDa vs 20 kDa vs met-GH

What Do Studies Say About HGH 191AA?

GH Receptor Signalling — Foundational Characterisation

The characterisation of GHR structure, dimerisation mechanism, and JAK2/STAT5 signalling pathway by Argetsinger et al. and subsequent work by the Bhatt and Carter laboratories established the molecular basis of HGH 191AA’s receptor pharmacology — providing the framework for all subsequent GH axis research and confirming the JAK2/STAT5 cascade as the primary genomic signalling pathway downstream of GHR engagement.

Key Citation

Argetsinger LS et al. (1993) — Identification of JAK2 as a growth hormone receptor-associated tyrosine kinase — Cell 74(2):237–244. DOI: 10.1016/0092-8674(93)90415-M

IGF-1 Axis and Anabolic Signalling

Landmark studies establishing the GH/IGF-1 axis — including the somatomedin hypothesis refinements by LeRoith, Laron, and colleagues — defined IGF-1 as the primary mediator of GH’s anabolic and growth-promoting effects, confirmed the liver as the primary source of circulating IGF-1, and established the research framework for GH deficiency and GH replacement biology that underpins current pre-clinical GH axis research.

Key Citation

LeRoith D et al. (2001) — The role of the insulin-like growth factor-I receptor in cancer — Annual Review of Medicine 52:108–123. DOI: 10.1146/annurev.med.52.1.108

GH Deficiency and Replacement Research

Extensive pre-clinical and clinical research using recombinant hGH has characterised the effects of GH deficiency across the lifespan — from childhood growth failure to adult-onset GH deficiency with associated body composition, metabolic, and quality-of-life effects — establishing the pharmacological profile of HGH 191AA replacement in deficiency models that forms the pre-clinical basis for current GH replacement research.

Key Citation

Consensus guidelines for the diagnosis and treatment of adults with GH deficiency II: a statement of the GH Research Society in association with the European Society for Pediatric Endocrinology — Eur J Endocrinol 157(6):695–700 (2007). DOI: 10.1530/EJE-07-0631

GH vs GH Secretagogues — Benchmarking Research

Comparative studies using HGH 191AA as the reference compound have benchmarked the efficacy of GH secretagogues — including CJC-1295, Ipamorelin, GHRP-2, GHRP-6, and Sermorelin — in terms of GH output, IGF-1 stimulation, and downstream anabolic effects. These comparative studies have established the relative potency and pharmacokinetic profiles of secretagogue classes relative to exogenous GH, providing the research foundation for dual-pathway GH secretagogue combination studies.

HGH 191AA and Body Composition Research

Pre-clinical studies in GH-deficient and GH-replete animal models using HGH 191AA have characterised GH’s effects on lean mass preservation, visceral adipose tissue reduction, and bone mineral density — establishing the research basis for GH’s role in body composition regulation and the metabolic consequences of GH axis decline with age.

HGH 191AA vs GH Secretagogues and GH Fragments — Research Comparison

Feature	HGH 191AA	CJC-1295 No DAC	Ipamorelin	HGH Frag 176-191
Compound Type	Full recombinant hGH	GHRH analogue	GH secretagogue (GHRP)	GH C-terminal fragment
GHR Binding	Direct — high affinity	None (stimulates GH release)	None (stimulates GH release)	None
IGF-1 Stimulation	Direct — high	Indirect (via GH release)	Indirect (via GH release)	None
Lipolytic Activity	Yes (direct GHR)	Indirect (via GH)	Indirect (via GH)	Direct — selective
Anabolic Activity	Full somatotropic	Via endogenous GH	Via endogenous GH	None
Insulin Antagonism	Yes (GHR-mediated)	Indirect	Indirect	None
Research Role	Gold-standard GH reference	Pulsatile GHRH agonist	GHS-R1a agonist	Selective lipolysis tool

Buy HGH 191AA UK — Product Specifications

Property	Detail
Full Name	Recombinant Human Growth Hormone 191AA / Somatropin
Also Known As	HGH 191AA, rhGH, hGH 191, Somatropin, 22 kDa GH
Amino Acids	191 (full-length mature sequence)
Molecular Weight	~22,124 Da (22 kDa)
Molecular Formula	C₉₉₀H₁₅₂₈N₂₆₂O₃₀₀S₇
Expression System	Recombinant DNA — E. coli or mammalian cell expression
Isoform	22 kDa monomer — predominant circulating GH isoform
GH Receptor Binding	Yes — direct, high-affinity GHR agonist
IGF-1 Stimulation	Yes — direct hepatic and peripheral IGF-1 induction
Purity	>99% (HPLC and MS verified)
Form	Lyophilised powder
Storage	Store dry at -20°C; protect from light and moisture; avoid repeated freeze-thaw cycles
Solubility	Bacteriostatic water or sterile water for injection (research grade)

Quality & Purity Assurance

Every batch of HGH 191AA from Peptides Lab UK is:

• >99% pure — HPLC and mass spectrometry verified
• Sequence-confirmed — full 191-amino acid bioidentical human GH sequence
• Supplied with a full Certificate of Analysis (COA) available on request
• Lyophilised powder format for maximum stability and extended shelf life
• Manufactured under strictly controlled laboratory conditions
• Consistent batch-to-batch quality for reproducible research outcomes

Why Buy HGH 191AA from Peptides Lab UK?

Peptides Lab UK is a trusted UK peptides supplier, providing research-grade compounds verified by independent HPLC and mass spectrometry testing. When you buy HGH 191AA in the UK from Peptides Lab UK, you receive:

• >99% purity, HPLC and MS verified, third-party tested
• Full COA documentation per batch
• Fast same-day UK dispatch with tracked delivery
• Competitive pricing with bulk research discounts available
• Trusted by researchers across the UK and Europe

Research Disclaimer

All products supplied by Peptides Lab UK are intended strictly for in vitro laboratory research and scientific study use only. They are not intended for human consumption, veterinary use, or any medical or therapeutic application. HGH 191AA (recombinant human growth hormone) is not a licensed medicine for general supply and is provided here solely as a research-grade compound for use in controlled laboratory settings. Recombinant human growth hormone is a prescription-only medicine in the UK and is classified as a prohibited substance under WADA anti-doping regulations. It is not approved by the MHRA or FDA for self-administration outside of authorised clinical frameworks. All research citations on this page relate to pre-clinical studies and peer-reviewed pharmacological research and do not constitute a claim of safety or therapeutic efficacy. Peptides Lab UK accepts no liability for any misuse of research compounds. By purchasing, you confirm that you are a qualified researcher and that the product will be used solely within a controlled laboratory environment in compliance with all applicable UK laws, regulations, and institutional guidelines.