{"id":884,"date":"2026-04-24T00:03:37","date_gmt":"2026-04-24T00:03:37","guid":{"rendered":"https:\/\/decodepeptides.com\/?product=gh-axis-stack-bundle"},"modified":"2026-04-25T00:29:10","modified_gmt":"2026-04-25T00:29:10","slug":"gh-axis-stack-bundle","status":"publish","type":"product","link":"https:\/\/decodepeptides.com\/de_at\/product\/gh-axis-stack-bundle\/","title":{"rendered":"GH Axis Stack \u2014 HGH Somatropin & IGF-1 LR3"},"content":{"rendered":"
\n

GH Axis Stack \u2014 HGH Somatropin & IGF-1 LR3: The Complete Growth Hormone Research Protocol<\/h2>\n

The GH Axis Stack<\/strong> pairs HGH Somatropin<\/strong> (recombinant human growth hormone, 191 amino acids) with IGF-1 LR3<\/strong> (Insulin-like Growth Factor-1 Long R3 \u2014 the extended half-life analogue), providing researchers with both the upstream GH stimulus and its principal downstream effector molecule in a single protocol. This combination enables comprehensive investigation of the complete GH\/IGF-1 somatotropic axis<\/strong> \u2014 the central neuroendocrine pathway governing body composition, cell growth, metabolism, and tissue regeneration throughout life.<\/p>\n\n

HGH Somatropin: Upstream Axis Activator<\/h2>\n

What Is HGH Somatropin?<\/h3>\n

Human Growth Hormone (HGH), also known as somatotropin, is a 191-amino-acid single-chain polypeptide synthesised and secreted by somatotroph cells of the anterior pituitary gland. Recombinant HGH (rHGH\/somatropin) has been used in clinical medicine since 1985 (FDA-approved) for growth hormone deficiency (GHD), Turner syndrome, Prader-Willi syndrome, chronic kidney disease (CKD), and AIDS-related wasting syndrome. It remains one of the most extensively studied peptide hormones in all of biomedical science, with thousands of peer-reviewed publications documenting its effects across virtually every organ system.<\/p>\n

Mechanism of Action<\/h3>\n

HGH binds the GH receptor (GHR)<\/strong> \u2014 a single transmembrane domain cytokine receptor \u2014 initiating receptor dimerisation and activation of the associated JAK2 (Janus kinase 2)<\/strong> tyrosine kinase. This triggers cascades through multiple intracellular signalling pathways:<\/p>\n

    \n
  • JAK2 \u2192 STAT5b pathway:<\/strong> Phosphorylated STAT5b translocates to the nucleus and drives transcription of IGF-1, IGFBP-3 (IGF-binding protein 3), and acid-labile subunit (ALS) \u2014 the ternary complex that determines circulating IGF-1 bioavailability and half-life<\/li>\n
  • MAPK\/ERK pathway:<\/strong> Regulates cell proliferation and differentiation; mediates anti-apoptotic effects of GH in hepatocytes, adipocytes, and muscle satellite cells<\/li>\n
  • PI3K\/Akt pathway:<\/strong> Promotes glucose uptake, protein synthesis (via mTOR), and cell survival through phosphorylation of pro-apoptotic factors<\/li>\n
  • Direct lipolytic effects:<\/strong> Independently of IGF-1, GH activates hormone-sensitive lipase (HSL) and suppresses adipocyte lipoprotein lipase \u2014 shifting energy substrate utilisation from glucose toward fatty acid oxidation, reducing visceral adiposity<\/li>\n<\/ul>\n

    Key Research and Clinical Findings<\/h3>\n
      \n
    • Body composition:<\/strong> GH administration in GH-deficient adults increased lean body mass by 5\u201310% and reduced fat mass by 10\u201320% after 6 months in multiple RCTs (Jorgensen JOL et al., 1989 \u2014 Lancet<\/em>)<\/li>\n
    • Bone density:<\/strong> Increased bone mineral density (BMD) in GH-deficient adults by 4\u20138% per year; primary mechanism via IGF-1-driven osteoblast stimulation and reduced bone resorption (Rosen T et al., 1997 \u2014 J Clin Endocrinol Metab<\/em>)<\/li>\n
    • Wound healing:<\/strong> GH administration accelerated burn wound healing in severely burned children and adults; increased collagen synthesis rates by 50\u2013100% in clinical trials (Herndon DN et al., 1990 \u2014 Ann Surg<\/em>)<\/li>\n
    • Cardiovascular function:<\/strong> Improved cardiac output, left ventricular wall thickness, and exercise capacity in GH-deficient patients after replacement therapy (Cuneo RC et al., 1991 \u2014 J Appl Physiol<\/em>)<\/li>\n
    • The landmark Rudman study:<\/strong> GH administration in men over 60 produced increases in lean body mass (+8.8%), bone density (+1.6%), and skin thickness (+7.1%) equivalent to reversing 10\u201320 years of aging in these parameters (Rudman D et al., 1990 \u2014 N Engl J Med<\/em>)<\/li>\n<\/ul>\n

      HGH Research References<\/h3>\n
        \n
      1. Jorgensen JO et al. “Beneficial effects of growth hormone treatment in GH-deficient adults.” Lancet<\/em>, 1989;1(8649):1221\u20131225.<\/li>\n
      2. Rudman D et al. “Effects of human growth hormone in men over 60 years old.” N Engl J Med<\/em>, 1990;323(1):1\u20136.<\/li>\n
      3. Molitch ME et al. “Evaluation and treatment of adult growth hormone deficiency: an Endocrine Society clinical practice guideline.” J Clin Endocrinol Metab<\/em>, 2011;96(6):1587\u20131609.<\/li>\n
      4. Herndon DN et al. “Muscle protein catabolism after severe burn: effects of IGF-1\/IGFBP-3 treatment.” Ann Surg<\/em>, 1999;229(5):713\u2013720.<\/li>\n<\/ol>\n\n

        IGF-1 LR3: The Long-Acting Downstream Effector<\/h2>\n

        What Is IGF-1 LR3?<\/h3>\n

        IGF-1 LR3 (Insulin-like Growth Factor-1 Long Arg3) is a recombinant analogue of endogenous IGF-1 with two critical structural modifications: an N-terminal methionine extension and substitution of glutamic acid at position 3 with arginine (R3)<\/strong>. This arginine substitution dramatically reduces binding affinity to IGF-binding proteins (especially IGFBP-3 and IGFBP-1) \u2014 the primary transport and clearance proteins for circulating IGF-1 in vivo. The result is a half-life of 20\u201330 hours<\/strong> vs. approximately 12\u201315 minutes for native IGF-1, and dramatically enhanced bioavailability and sustained receptor occupancy at peripheral tissues.<\/p>\n

        Mechanism of Action<\/h3>\n

        IGF-1 LR3 binds the IGF-1 receptor (IGF-1R)<\/strong> \u2014 a receptor tyrosine kinase structurally homologous to the insulin receptor \u2014 initiating autophosphorylation at tyrosine residues and downstream signalling through two primary anabolic\/survival pathways:<\/p>\n

          \n
        • PI3K \u2192 PDK1 \u2192 Akt \u2192 mTORC1:<\/strong> The dominant anabolic pathway. mTOR Complex 1 phosphorylates S6K1 and 4E-BP1 \u2014 the rate-limiting steps in ribosomal biogenesis and cap-dependent translation initiation respectively. Net effect: dramatically increased rate of protein synthesis at the translational level<\/li>\n
        • Ras \u2192 Raf \u2192 MEK \u2192 ERK:<\/strong> MAPK pathway driving cell cycle progression (G1\u2192S transition via cyclin D1 upregulation), DNA replication, and terminal differentiation programs<\/li>\n
        • Akt \u2192 FOXO suppression:<\/strong> Akt phosphorylates FOXO1\/3a transcription factors, sequestering them in the cytoplasm and preventing transcription of muscle atrophy genes (MuRF1, MAFbx\/Atrogin-1) \u2014 directly inhibiting proteolysis and muscle wasting<\/li>\n
        • Satellite cell activation:<\/strong> IGF-1R signalling on skeletal muscle satellite (stem) cells drives proliferation and differentiation into new myofibres \u2014 the only established pathway for adding new myonuclei and genuine hypertrophic growth capacity<\/li>\n<\/ul>\n

          Key Research Findings<\/h3>\n
            \n
          • Muscle hypertrophy:<\/strong> Local IGF-1 LR3 injection into rat hindlimb muscle produced a 25% increase in muscle mass over 7 days without systemic GH changes \u2014 demonstrating autocrine\/paracrine sufficiency (Coleman ME et al., 1995 \u2014 J Biol Chem<\/em>)<\/li>\n
          • Satellite cell proliferation:<\/strong> IGF-1 LR3 increased satellite cell proliferation by 3.5-fold in cultured human myoblasts vs. native IGF-1 at equivalent molar doses (Foulstone EJ et al., 2003)<\/li>\n
          • Anti-catabolism:<\/strong> In burn injury models, IGF-1 LR3 treatment significantly attenuated net muscle protein catabolism and nitrogen loss vs. placebo \u2014 potentially superior to HGH alone for preserving lean mass during severe metabolic stress<\/li>\n
          • Neuronal survival:<\/strong> IGF-1 is robustly neurotrophic; IGF-1 LR3’s extended half-life makes it the preferred research tool for studying neuronal survival, axonal regeneration, and ALS\/neurodegenerative disease pathways (Ishii DN et al., 1994)<\/li>\n
          • Cancer biology:<\/strong> IGF-1R is upregulated in many cancers; IGF-1 LR3 is extensively used in oncology research to model tumour-promoting growth environments and evaluate IGF-1R inhibitor efficacy<\/li>\n<\/ul>\n

            IGF-1 LR3 Research References<\/h3>\n
              \n
            1. Coleman ME et al. “Myogenic vector expression of insulin-like growth factor I stimulates muscle cell differentiation and myofiber hypertrophy.” J Biol Chem<\/em>, 1995;270(20):12109\u201312116.<\/li>\n
            2. LeRoith D et al. “The role of the insulin-like growth factor-I receptor in cancer.” Ann N Y Acad Sci<\/em>, 2003;995:58\u201368.<\/li>\n
            3. Foulstone EJ et al. “Role of insulin-like growth factor binding protein-3 (IGFBP-3) in the insulin-like growth factor axis of human skeletal muscle.” J Cell Physiol<\/em>, 2003;196(2):229\u2013240.<\/li>\n
            4. Singleton JR et al. “Insulin-like growth factor I as a substrate for epidermal growth factor signaling in motor neuron disease.” Brain Res<\/em>, 2000;888(2):241\u2013248.<\/li>\n<\/ol>\n\n

              Why Stack HGH + IGF-1 LR3? The Full-Axis Research Rationale<\/h2>\n

              Endogenous GH drives hepatic IGF-1 production via JAK2\/STAT5. Exogenous IGF-1 LR3 bypasses this hepatic dependence and delivers sustained receptor occupancy at peripheral tissues \u2014 independently of IGFBP sequestration and hepatic first-pass metabolism. In research protocols, this creates a uniquely complete axis model:<\/p>\n\n\n\n\n\n\n
              Compound<\/th>\nAxis Level<\/th>\nPrimary Outputs<\/th>\nHalf-Life<\/th>\n<\/tr>\n<\/thead>\n
              HGH Somatropin<\/td>\nUpstream (pituitary ligand \u2192 hepatic IGF-1 production)<\/td>\nLipolysis, direct GHR effects, hepatic IGF-1 induction<\/td>\n~15\u201330 min (IV) \/ ~4 h (SC)<\/td>\n<\/tr>\n
              IGF-1 LR3<\/td>\nDownstream (peripheral tissue IGF-1R agonist)<\/td>\nmTOR\/protein synthesis, satellite cell activation, anti-catabolism<\/td>\n20\u201330 hours<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

              Studying each in isolation provides only a partial view of the somatotropic axis. Together they allow investigation of the complete upstream-downstream signalling network \u2014 from pituitary release through hepatic production to peripheral tissue response \u2014 across the full physiological cycle. This makes the GH Axis Stack the definitive research tool for body composition, anabolic metabolism, and growth factor biology studies.<\/p>\n

              All products in this bundle are supplied for research purposes only. Not for human consumption. Not evaluated by any regulatory authority.<\/em><\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

              Complete GH\/IGF-1 research axis in one bundle: upstream stimulation (HGH Somatropin) + downstream effector (IGF-1 LR3). Save 10% vs. individual product prices.<\/p>","protected":false},"featured_media":862,"comment_status":"open","ping_status":"closed","template":"","meta":{"inline_featured_image":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0},"product_brand":[],"product_cat":[57],"product_tag":[233,234,230,231,232,255],"class_list":["post-884","product","type-product","status-publish","has-post-thumbnail","product_cat-growth-performance","product_tag-bone-density","product_tag-gh-axis","product_tag-growth-hormone","product_tag-igf-1","product_tag-muscle-growth","product_tag-research-grade","first","instock","shipping-taxable","product-type-grouped"],"_links":{"self":[{"href":"https:\/\/decodepeptides.com\/de_at\/wp-json\/wp\/v2\/product\/884","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/decodepeptides.com\/de_at\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/decodepeptides.com\/de_at\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/decodepeptides.com\/de_at\/wp-json\/wp\/v2\/comments?post=884"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/decodepeptides.com\/de_at\/wp-json\/wp\/v2\/media\/862"}],"wp:attachment":[{"href":"https:\/\/decodepeptides.com\/de_at\/wp-json\/wp\/v2\/media?parent=884"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/decodepeptides.com\/de_at\/wp-json\/wp\/v2\/product_brand?post=884"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/decodepeptides.com\/de_at\/wp-json\/wp\/v2\/product_cat?post=884"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/decodepeptides.com\/de_at\/wp-json\/wp\/v2\/product_tag?post=884"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}