# IGF-1 (Mecasermin) > The downstream effector of growth hormone — a 70-amino-acid recombinant protein, structurally a cousin of proinsulin, that carries out most of GH’s growth signal. - Also known as: Insulin-like growth factor 1, Mecasermin, Increlex, Somatomedin C, rhIGF-1 - Class: Growth Hormone, Longevity - FDA approved: Yes - Canonical page: https://americanpeptide.com/catalog/igf-1 ## Overview IGF-1 is the molecule that does much of growth hormone’s work. It is a 70-amino-acid single-chain protein (~7.6 kDa) with three disulfide bonds, structurally homologous to proinsulin — which is why insulin and IGF-1 signaling overlap. Produced mainly in the liver under GH stimulation, it is the mediator most responsible for GH’s anabolic and growth-promoting effects. The recombinant therapeutic version, mecasermin, is FDA-approved for severe IGF-1 deficiency. It pairs naturally with somatropin in this catalog: GH is the signal, IGF-1 is the message that actually reaches the tissues. Where somatropin is the broadcast, IGF-1 is the signal received. Growth hormone acts on the liver and other tissues to induce IGF-1, and it is IGF-1 — acting through its own tyrosine-kinase receptor — that mediates most of the downstream growth and anabolic effects. Its structural kinship to proinsulin is not a coincidence: the IGF and insulin systems are evolutionary relatives, which is why IGF-1 has weak insulin-like (hypoglycemic) activity and why dosing is constrained by that overlap. The therapeutic form, mecasermin (Increlex), is recombinant human IGF-1 approved in 2005 for children with severe primary IGF-1 deficiency or growth-hormone insensitivity — the Laron syndrome population, in whom GH itself does not work because the receptor or its signaling is broken. In those patients, supplying IGF-1 directly bypasses the failed step. IGF-1 carries the same two layers of drama as growth hormone, sharpened. It is banned in sport and has been a recurring doping target; the most public episode was the 2013 "deer antler velvet spray" affair, in which an IGF-1-marketed product was tied to several athletes — a reminder that much of what is sold as IGF-1 outside medicine is unverified. And the longevity paradox is, if anything, cleaner here: low IGF-1 signaling is one of the most reproducible pro-longevity signals in biology, with IGF-1-pathway mutants living longer across species and Laron-syndrome individuals showing strikingly low cancer and diabetes incidence. A protein marketed for anti-aging sits on the very axis whose suppression extends life. ## Mechanism Binds the IGF-1 receptor (a tyrosine kinase) and, with lower affinity, the insulin receptor, activating PI3K/AKT and MAPK signaling to drive cell growth, proliferation, and survival. Circulating IGF-1 is largely bound to IGF-binding proteins, which modulate its availability. ## Chemistry | Property | Value | | --- | --- | | Molecular formula | C331H512N94O101S7 | | Molecular weight | 7649 Da | | CAS number | 68562-41-4 | | UniProt | [P05019](https://www.uniprot.org/uniprotkb/P05019) | ## Sequence ``` GPETLCGAELVDALQFVCGDRGFYFNKPTGYGSSSRRAPQTGIVDECCFRSCDLRRLEMYCAPLKPAKSA ``` ## Research areas Studied in: Severe primary IGF-1 deficiency, GH/IGF-1 axis, Growth disorders, Longevity. Guides on this site: - [Growth Hormone & Body Composition](https://americanpeptide.com/research-areas/growth-hormone-axis): Secretagogues studied for GH release, IGF-1, and body composition. ## Key research - Severe primary IGF-1 deficiency — the approved use of mecasermin, supplying IGF-1 where GH signaling has failed. - GH/IGF-1 axis — IGF-1 is the principal mediator of growth hormone’s anabolic effects. - Insulin cross-talk — structural homology to proinsulin gives it weak hypoglycemic activity, a dosing constraint. - Longevity paradox — reduced IGF-1 signaling tracks with extended lifespan and lower cancer/diabetes risk (Laron syndrome). - Doping target — WADA-banned; "deer antler velvet" IGF-1 products are a notable case of unverified marketing. - IGF-binding proteins — circulating IGF-1 is mostly protein-bound, which regulates its activity and half-life. - Research analogs & splice variants — IGF-1 LR3 is a long-acting modified analog studied for systemic hypertrophy, while MGF (mechano growth factor) is a local IGF-1 splice variant studied for satellite-cell activation after muscle damage. ## Storage, handling & synthesis **Storage.** Mecasermin is stored refrigerated (2–8 °C) and protected from light; it must not be frozen, and reconstituted/in-use solution is used within the label’s limited window. **Handling.** A folded disulfide-bonded protein, sensitive to heat, freeze–thaw, and agitation. Because of its insulin-like activity, hypoglycemia is a specific handling/clinical concern. **Synthesis.** Recombinant IGF-1 is expressed (classically in E. coli), refolded to its native three-disulfide structure, and purified by chromatography. Release testing is protein-grade — peptide mapping, mass spectrometry, correct disulfide pairing, cell-based potency, host-cell-protein and endotoxin limits — not an HPLC purity figure alone. ## FAQs ### What is IGF-1? Insulin-like growth factor 1 — a 70-amino-acid protein, made mainly in the liver under growth-hormone stimulation, that carries out most of GH’s growth-promoting effects. The recombinant drug mecasermin (Increlex) is approved for severe IGF-1 deficiency. ### How is IGF-1 related to growth hormone? GH stimulates the liver to produce IGF-1, and IGF-1 then does much of the actual signaling to tissues. That is why IGF-1 can treat people whose GH does not work (Laron syndrome). ### Why is it called "insulin-like"? IGF-1 is structurally homologous to proinsulin and binds the insulin receptor weakly, giving it mild insulin-like (glucose-lowering) effects. ### Is this medical advice? No — this is a research and educational reference. Mecasermin is a prescription biologic; much of what is sold as IGF-1 outside medicine is unverified. ## Latest research Recent trials and publications mentioning IGF-1, pulled automatically from ClinicalTrials.gov and PubMed (unfiltered search results, refreshed daily). ### Recent trials - [A Clinical Trial to Assess the Effect of AP-Brain Collagen Peptides on the Improvement of Attention, Focus, and Memory in Stressed But Otherwise Healthy Individuals](https://clinicaltrials.gov/study/NCT07572240) — RECRUITING · NA · NCT07572240 - [Long-term Safety and Effectiveness of Growtropin®-II Treatment in Children With Short Stature](https://clinicaltrials.gov/study/NCT04798690) — RECRUITING · NCT04798690 - [Finding the Best Tamoxifen Dose for Breast Cancer Risk Reduction in Premenopausal Women, RENAISSANCE Trial](https://clinicaltrials.gov/study/NCT06184750) — RECRUITING · PHASE2 · NCT06184750 - [Comparison of Low, Moderate and High Carbohydrate Diet on Insulin Requirements and Metabolic Control in Type 1 Diabetes](https://clinicaltrials.gov/study/NCT03761186) — COMPLETED · NA · NCT03761186 - [Role of Estrogen on Skeletal Outcomes in FHA](https://clinicaltrials.gov/study/NCT07010146) — RECRUITING · PHASE2 · NCT07010146 - [Harm Reduction Intervention for Anabolic-androgenic Steroids Users: a Randomized Controlled Trial](https://clinicaltrials.gov/study/NCT07039539) — NOT_YET_RECRUITING · NA · NCT07039539 --- Source: AmericanPeptide.com — https://americanpeptide.com/catalog/igf-1 Data license: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Attribution: AmericanPeptide.com. Research reference only — computational and educational content, not medical advice.