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GH Axis · Reference monograph

Insulin-like growth factor 1 (somatomedin C)

Reference compound — not available from Purity Peptides. Shown for research context.

Overview

Insulin-like growth factor 1 (IGF-1), historically called somatomedin C, is a 70-amino-acid single-chain polypeptide with three disulfide bonds and close structural similarity to proinsulin. It is produced mainly by the liver under the control of pituitary growth hormone (GH), and it is also made locally in muscle, bone, cartilage and many other tissues, where it acts in an autocrine and paracrine fashion.

The somatomedin hypothesis, proposed in the late 1950s by Salmon and Daughaday after they found that GH stimulated cartilage sulfate uptake only in the presence of serum, framed IGF-1 as the mediator of many GH actions. Today circulating IGF-1 is one of the most widely measured biomarkers of GH-axis activity. A recombinant form, mecasermin, is an approved prescription medicine for severe primary IGF-1 deficiency. In research settings IGF-1 is used to study receptor tyrosine kinase signalling, growth physiology, ageing biology and the hepatic response to GH.

Mechanism studied

  1. Pituitary GH
  2. Liver
  3. IGF-1
  4. Anabolic signalling

IGF-1 binds the IGF-1 receptor (IGF-1R), a heterotetrameric receptor tyrosine kinase related to the insulin receptor. Ligand binding triggers autophosphorylation and recruitment of insulin receptor substrate proteins and Shc, activating two main branches: the PI3K-Akt-mTOR pathway, associated with protein synthesis and cell survival, and the Ras-MAPK pathway, associated with proliferation. In circulation, most IGF-1 is carried in a ternary complex with IGF-binding protein 3 and the acid-labile subunit, which prolongs its half-life and restricts tissue access. Six IGF-binding proteins and their proteases therefore shape local bioavailability, a key variable in experimental design.

Research highlights

  • 01The somatomedin concept emerged in 1957, and IGF-1 and IGF-2 were sequenced by Rinderknecht and Humbel in 1978.
  • 02Liver-specific IGF-1 knockout mice showed markedly reduced circulating IGF-1 with largely preserved growth, highlighting the role of locally produced IGF-1.
  • 03Laron syndrome, caused by GH receptor defects, provides a human genetic model of lifelong IGF-1 deficiency studied in growth and ageing research.
  • 04Reduced IGF-1 signalling extends lifespan in worms, flies and mice, making the pathway a major topic in ageing biology.
  • 05Open questions include how IGF-binding protein proteolysis controls tissue-level activity and how IGF-1R and insulin receptor hybrids signal.

Latest published research

54,731 papers on PubMed →

  1. A bioactivity-enhanced thermosensitive amnion-derived hydrogel with sustained IGF-1 release: A multitargeted and efficient strategy for corneal injury repair

    Xie M et al. · Bioactive materials · 2027 Feb · PMID 42781431

  2. Updated Protocols for 3D and 2D Culture and Histological Analysis of Intestinal Organoids

    Hanyu H et al. · Methods in molecular biology (Clifton, N.J.) · 2027 · PMID 42763855

  3. Imeglimin provides dual hepatic and skeletal muscle protection in experimental MASH-associated sarcopenia

    Osaki Y et al. · Biochimica et biophysica acta. Molecular basis of disease · 2027 Jan · PMID 42759777

  4. Intermittent theta-burst stimulation in ischemic stroke: a mitochondria-centered framework connecting microglial reprogramming and neuronal survival

    Liu Y et al. · Experimental neurology · 2027 Jan · PMID 42753899

  5. Stigmasterol alleviates central precocious puberty by targeting the IGF-1/PI3K/Akt/mTOR signaling pathway and modulating the Kisspeptin/GnRH axis

    Dong L et al. · Biochimica et biophysica acta. Molecular basis of disease · 2027 Jan · PMID 42562054

  6. The effect of the Mediterranean diet combined with physical activity on cognitive function in older adults: a scoping review

    Yang Y et al. · Journal of the International Society of Sports Nutrition · 2026 Dec 31 · PMID 42483938

  7. Systemic and local delivery of siRNA to the CNS and periphery via anti-IGF1R antibody conjugation

    Tian M et al. · Molecular therapy. Nucleic acids · 2026 Dec 8 · PMID 42927339

  8. Jianpi Qutan Formula attenuates vulnerable plaques by regulating IGFBP3

    Yang M et al. · Journal of ethnopharmacology · 2026 Dec 6 · PMID 42302944

Live feed from PubMed (NCBI) for “IGF-1 (Insulin-like Growth Factor 1)”, updated 2026-10-30. Listing a paper is not an endorsement of its findings.

Registered studies

337 on ClinicalTrials.gov →

From the public ClinicalTrials.gov registry for “IGF-1 (Insulin-like Growth Factor 1)”, updated 2026-10-30. Shown for research context only; Purity Peptides products are not for human use.

Key references

  1. [1]WADA — Prohibited List of Substances and Methods
  2. [2]Mecasermin prescribing information — FDA / EMA
  3. [3]PubMed — reviews on IGF-1 and the somatotropic axis

FAQ

  • GH released from the pituitary acts on hepatic GH receptors to stimulate IGF-1 production via JAK2-STAT5 signalling. IGF-1 in turn feeds back to suppress GH secretion at the hypothalamus and pituitary. Because IGF-1 levels are relatively stable through the day, it is a common integrated marker of GH activity.

  • Mecasermin is recombinant human IGF-1 manufactured using DNA technology. It is an approved prescription medicine for severe primary IGF-1 deficiency, a rare condition in which GH is present but fails to generate adequate IGF-1. A related complex with IGFBP-3, mecasermin rinfabate, was developed but is no longer widely available.

  • Yes. IGF-1 and its analogues are listed under section S2 of the World Anti-Doping Agency Prohibited List as growth factors. Detection research focuses on IGF-1 and procollagen peptide markers. Researchers should always check the current list, which is updated annually.

FOR RESEARCH USE ONLY.Not for human or veterinary use. Not intended to diagnose, treat, cure, or prevent any disease.

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