IGF-1 DES is native human insulin-like growth factor 1 with its first three amino acids — Gly-Pro-Glu — removed, leaving a 67-residue protein of 7,371.30 g/mol. That single deletion removes the glutamate residue the IGF binding proteins rely on for high-affinity contact, so the truncated molecule circulates and acts largely unbuffered by the IGFBP system while retaining full agonist activity at the IGF-1 receptor. Unlike most engineered analogues, IGF-1 DES (1-3) is not a laboratory invention: it was first isolated from bovine colostrum and from brain tissue, and is generated in vivo by a specific N-terminal protease.
MyPeptide supplies IGF-1 DES (1-3) as a lyophilized powder in 0.1 mg and 1 mg vials within the IGF and muscle peptides range. Supplied for laboratory research only; not for human or veterinary use.
What is IGF-1 DES?
The name is descriptive: des is the chemical prefix for a deleted group, and (1-3) identifies which residues are missing. Full-length IGF-1 is a 70-residue single-chain protein with a proinsulin-like fold and three disulfide bridges, produced mainly by hepatocytes under growth hormone control. IGF-1 DES is that same chain starting at residue 4, so the receptor-binding surface, the disulfide pattern and the overall fold are unchanged; only the flexible N-terminal tripeptide is gone.
Catalogue identifiers are CAS 112603-35-7 and a molecular weight of 7,371.30 g/mol, roughly 278 Da lighter than native IGF-1. Because it is a 67-residue protein it is produced by recombinant expression rather than stepwise synthesis, and is supplied as a lyophilized powder.
Origin and structure
IGF-1 DES occupies an unusual position: it is simultaneously a naturally occurring peptide and a designed research tool. It was identified in bovine colostrum in the late 1980s and subsequently in porcine uterus and mammalian brain tissue, and an acid protease that cleaves the Gly-Pro-Glu tripeptide from IGF-1 has been described. That reaction also releases GPE (glypromate) itself, a tripeptide with its own small neuroprotection literature independent of the IGF-1 receptor — so the cleavage produces two biologically interesting fragments rather than one active molecule and one waste product.
The functional consequence of the deletion is confined to binding-protein contact. Glutamate 3 makes an electrostatic contact with the IGFBP surface; removing it has been reported to lower affinity for the binding proteins by one to two orders of magnitude, depending on which IGFBP is measured. Receptor affinity is essentially preserved, and in some binding studies IGF-1 DES has been reported to bind IGF-1R slightly more tightly than the full-length protein.
How IGF-1 DES is thought to work
The proximate mechanism is straightforward agonism at IGF-1R, an α2β2 receptor tyrosine kinase. Ligand binding drives β-subunit autophosphorylation, recruitment of insulin receptor substrate adaptors, and signalling through PI3K/Akt/mTOR — the arm associated in the literature with protein synthesis and cell survival readouts — and through Ras/MEK/ERK, associated with proliferation.
What distinguishes DES from native IGF-1 experimentally is not the signal but the availability. In a system containing IGF binding proteins — serum-containing medium, conditioned medium from IGFBP-secreting cells, or intact tissue — most added native IGF-1 is captured and held. The same molar amount of IGF-1 DES stays largely free. Reported apparent potency differences of several-fold up to roughly tenfold in such systems track the IGFBP content of the model rather than any intrinsic property of the molecule: in a binding-protein-free assay, DES and native IGF-1 behave similarly.
A second, subtler point concerns tissue with active IGFBP proteolysis. Where proteases release IGF-1 from its binding proteins locally, the advantage of a binding-protein-evading analogue narrows. This is one of the reasons investigators choose deliberately between DES and the substitution-based analogue rather than treating them as equivalents.
What the research has examined
Cell-culture potency and IGFBP dependence
The best-characterised body of work compares DES with native IGF-1 across cell systems differing in binding-protein content. Fibroblast, myoblast and osteoblast cultures have been used to show that the potency gap widens as IGFBP levels rise — the observation that established the mechanism. These are in-vitro studies with defined readouts such as thymidine incorporation and receptor phosphorylation.
Skeletal muscle and satellite cell models
C2C12 and primary myoblast work has used IGF-1 DES to probe proliferation and differentiation signalling where secreted IGFBP-5 and IGFBP-6 would otherwise confound interpretation. Findings are cell-level and are not evidence about whole-organism outcomes.
Neural and colostrum-derived roles
Because the molecule occurs naturally in brain tissue, several rodent studies have examined DES(1-3) IGF-1 in neuronal survival and injury models, often alongside the released GPE tripeptide. This literature is preclinical and exploratory.
Comparative analogue work
IGF-1 DES is routinely studied against IGF-1 LR3, which reaches the same binding-protein objective by substituting arginine at position 3 and adding an N-terminal extension. The two differ in size, isoelectric point, reported clearance and behaviour in proteolytically active tissue; the practical selection criteria are set out in our IGF-1 LR3 vs IGF-1 DES comparison, with background on the engineering rationale in why these modifications exist.
Forms and sizes we supply
| Attribute | Specification |
|---|---|
| Product | IGF-1 DES (1-3) |
| Also known as | DES(1-3) IGF-1, des-Gly-Pro-Glu IGF-1 |
| Form | Lyophilized powder, sealed glass vial |
| Available sizes | 0.1 mg, 1 mg |
| Purity | ≥99% by HPLC, lot-matched COA available |
| CAS number | 112603-35-7 |
| Molecular weight | 7,371.30 g/mol |
| Chain length | 67 residues (native IGF-1 minus Gly-Pro-Glu) |
| Key modification | Deletion of residues 1–3, removing the Glu3 IGFBP contact |
| Primary target | IGF-1 receptor (IGF-1R) |
| Intended use | Laboratory research only |
The 0.1 mg vial covers plate-scale culture work, where working concentrations sit in the nanogram-per-millilitre range; the 1 mg vial is the practical unit for a longer series that should run on a single lot. Supplier checks are covered in our IGF-1 DES buying guide.
Reconstitution and storage in a lab context
IGF-1 DES is handled as a recombinant protein, not as a small synthetic peptide. Solubility at neutral pH is limited, so it is normally reconstituted in a dilute acid — 10 mM hydrochloric acid or 0.1% acetic acid are the conventions in published product literature — and then diluted into the assay buffer or medium. Adding neutral buffer directly to the cake risks partial dissolution and aggregation, which presents as inconsistent activity rather than as visible turbidity.
The concentration arithmetic is simple: a 1 mg vial made up to 1 mL gives 1 mg/mL, or 1,000 mcg/mL, and 0.1 mL of that stock contains 100 mcg. Working stocks are typically several dilutions further down, at which point adsorption to tube walls becomes the dominant loss mechanism — the standard countermeasure is a carrier protein such as 0.1% bovine serum albumin. The general procedure is in our reconstitution guide.
Sealed lyophilized vials are stored at −20 °C or below, protected from light and moisture. Reconstituted stock is aliquoted at once and frozen, because repeated freezing and thawing is the main practical threat to a disulfide-bonded 7 kDa protein. Broader handling practice is set out in how to store peptides.
Purity, COA and how to read it
For a recombinant product the certificate should do more than quote a purity percentage. The mass spectrometry result is the identity check that matters most here: an observed mass near 7,371 g/mol confirms the truncated analogue, while a value near 7,649 g/mol would indicate full-length IGF-1 and a value above 9,000 g/mol would indicate the LR3 analogue. Because the three products look similar on a label and very different on a spectrum, this line is worth reading carefully. An SDS-PAGE lane adds information a reversed-phase trace can hide, particularly dimers and clipped species, and endotoxin content is relevant wherever the material will go into cell culture. Our guide to reading a peptide certificate of analysis walks through each section.
Regulatory status
IGF-1 DES (1-3) has no marketing authorisation as a medicine anywhere. Recombinant human IGF-1 (mecasermin) is an approved prescription product for a rare growth disorder, but that is the full-length 70-residue molecule and is a different substance from the truncated analogue supplied here. Material on this site is a research-use-only reagent for qualified laboratory personnel, not a supplement or a medicine, and is not supplied for human or veterinary administration. IGF-1 and its analogues are prohibited in sport under anti-doping rules.
Related molecules and further reading
The closest comparators are IGF-1 LR3, the substitution-and-extension analogue, and MGF, the E-domain peptide from the IGF-1 Ec splice variant — a different molecule entirely that does not act at IGF-1R and answers a different experimental question.