F tier · safety concern
ClinicalTrials.gov returns zero registered studies and PubMed zero clinical-trial records for des(1-3)IGF-I, and the 1996 review written by the group that isolated and characterised the molecule states that 'clinical opportunities for des(1-3)IGF-I have not yet been evaluated' — a statement that still stands three decades later. It is supplied only as a research reagent whose stated potency assay is proliferation of human breast cancer cells.
igf-1 des
des(1-3)IGF-1 is a naturally occurring truncated form of insulin-like growth factor-I, 67 residues instead of 70, produced by post-translational removal of the N-terminal Gly-Pro-Glu tripeptide and isolated from bovine colostrum, human brain and porcine uterus. Losing the glutamate at position 3 sharply reduces its affinity for the IGF-binding proteins, which makes it roughly ten times more potent than intact IGF-I in cultured cells. Its documented use is as a cell-culture and receptor-biology research reagent; there has never been a human trial of any kind.
// we supply this one
available as a research reagent
≥ 95% (SDS-PAGE / HPLC) · lyophilised powder · batch certificate published. Grade F above is our own and is not adjusted because we stock it.
the explanation
This is the body's own IGF-1 growth signal with the first three building blocks snipped off. That small change stops the carrier proteins in blood from holding on to it, so it hits its receptor harder in a dish. It has never been given to a person in a study, and the only IGF-1 medicine that actually exists — mecasermin, sold as Increlex — is the full-length molecule, not this one.
regulatory status
Not approved anywhere; research-use-only reagent — the licensed IGF-1 medicine is a different molecule
des(1-3)IGF-1 holds no marketing authorisation in any jurisdiction and is supplied under a research-use-only notice stating it 'is for research use only and is not approved for use in humans or in clinical diagnosis'. The approved IGF-1 medicine is mecasermin (Increlex), full-length 70-residue recombinant human IGF-1: authorised in the EU on 3 August 2007 under exceptional circumstances, and available in the UK as a prescription-only medicine under PL 08498/0041 for growth failure in children and adolescents from 2 to 18 years with confirmed severe primary IGF-1 deficiency. That is a separate molecule with its own label, contraindicated in active or suspected neoplasia. Under the 2026 WADA Prohibited List, S2.3 names 'Insulin-like growth factor 1 (IGF-1, mecasermin)' as prohibited at all times, and the list extends to substances of similar structure or biological effect, which captures truncated analogues. It is not a lawful UK food-supplement ingredient and is not sold or recognised as one.
how it works · proposed mechanism
The entire pharmacological argument for des(1-3)IGF-1 rests on one deletion: removing three residues removes the brake that binding proteins normally apply to IGF-1.
Loss of Glu3 defeats the IGFBPs
The absence of glutamate at position 3 sharply lowers affinity for the IGF-binding proteins, so the variant does not form the plasma complexes that normally sequester IGF-I. Its discoverers attribute the roughly ten-fold potency advantage in cultured cells directly to this reduced binding rather than to any change in receptor affinity.
Same receptor, less restraint
des(1-3)IGF-1 signals through the type 1 IGF receptor much as native IGF-I does, driving the usual PI3K/Akt and MAPK outputs. The supplier's validated potency assay is proliferation of serum-free MCF-7 human breast cancer cells, so mitogenicity is the declared readout of activity, not an incidental observation.
Faster clearance, wider distribution
In rats, escaping the binding proteins produced substantially faster plasma clearance and a larger steady-state volume of distribution than intact IGF-I, with more tracer reaching adrenals, brain, skin and gut. The authors proposed that binding proteins normally impede transfer of growth factors to tissue and that rapidly cleared analogues may therefore be more potent in vivo — potency by shorter, wider exposure, not longer exposure.
An endogenous molecule, not an invention
Unlike engineered analogues such as IGF-1 LR3, des(1-3)IGF-I occurs naturally, having been isolated from bovine colostrum, human brain and porcine uterus, and is thought to arise from post-translational cleavage of IGF-I. The removed tripeptide, Gly-Pro-Glu, is itself neuroactive, so the parent molecule yields two separate signalling species.
what’s reported
evidence shape
7 sourcesThe composition of the cited literature by study type. This describes the shape of the evidence, not its quality — and it does not by itself set the grade.
⚠ the catch
The central error in this market is conflating des(1-3)IGF-1 with mecasermin. Mecasermin is full-length 70-residue recombinant human IGF-1, EU-authorised on 3 August 2007 and a UK prescription-only medicine under PL 08498/0041; des(1-3)IGF-1 is a 67-residue truncation with zero registered trials, zero clinical-trial publications and no human pharmacokinetics at all. Every safety and efficacy fact people cite for 'IGF-1' belongs to the licensed molecule, whose own label carries a contraindication in active or suspected neoplasia and a warning of increased benign and malignant neoplasia risk. The second error is the half-life claim: the one published clearance study found the truncated variant left rat plasma about 3.8 times faster than intact IGF-I, so the product is marketed on a pharmacokinetic property that measurement contradicts. It is also absent entirely from the 2026 endocrinology review of self-administered GH-axis peptides, which covered IGF-1 LR3 and PEG-MGF but not this compound — there was nothing to review.
key published findings
- Discoverers' review (Ballard, Wallace, Francis, Read, Tomas; Int J Biochem Cell Biol 1996;28:1085-1087): des(1-3)IGF-I 'has been isolated from bovine colostrum, human brain and porcine uterus', 'probably results from post-translational cleavage of IGF-I', 'generally is about 10-fold more potent than IGF-I at stimulating hypertrophy and proliferation of cultured cells, a consequence of much reduced binding to IGF-binding proteins, in turn caused by the absence of the glutamate at position 3', and — decisively — 'clinical opportunities for des(1-3)IGF-I have not yet been evaluated'.
- Rat pharmacokinetics (Ballard et al., J Endocrinol 1991;128:197-204): association with plasma IGF-binding proteins was 'essentially absent' for des(1-3)IGF-I, total plasma clearance was roughly 3.8-fold faster than for IGF-I and about 3.4-fold faster than for IGF-II, steady-state volume of distribution was roughly 2.8-fold larger than for IGF-I, and tracer reaching adrenals, brain, skin, stomach, duodenum, ileum plus jejunum and colon ranked des(1-3)IGF-I > IGF-I > IGF-II.
- GH-deficient mice (Gillespie, Read, Bagley, Ballard; J Endocrinol 1990;127:401-405): over three weeks des(1-3)IGF-I increased total length and nose-rump length more than intact IGF-I at matched exposure and raised kidney and heart weights where intact IGF-I did not, while body-weight changes were not statistically significant — the authors concluded the in-vitro potency advantage 'also applies in vivo to at least one strain of GH-deficient animals'.
- Reagent specification (Bio-Techne/Novus NBP2-34947): a 67-residue E. coli-derived chain, predicted mass 7.4 kDa, greater than 97% pure by SDS-PAGE and HPLC, potency assessed by proliferation of serum-free MCF-7 human breast cancer cells, and labelled 'for research use only and is not approved for use in humans or in clinical diagnosis'.
- Registry and literature searches: exact-phrase ClinicalTrials.gov searches for 'des(1-3)', 'DES(1-3)IGF-I' and 'IGF-1 DES' each return zero studies, and a PubMed search restricted to the clinical-trial publication type returns zero records — against roughly 180 PubMed records overall, essentially all in vitro or animal work.
- The separate approved molecule: mecasermin (Increlex), full-length recombinant human IGF-1, received EU marketing authorisation on 3 August 2007 under exceptional circumstances and is a UK prescription-only medicine (PL 08498/0041) for severe primary IGF-1 deficiency; its SmPC contraindicates use in active or suspected neoplasia and warns of 'an increased risk of benign and malignant neoplasia in children and adolescents treated with INCRELEX'.
limitations of the evidence
- There is no human evidence of any kind — no pharmacokinetics, no safety data, no efficacy signal, no case series, not even an uncontrolled report in the indexed literature.
- The supporting animal work is from 1990-1994 and was designed to test binding-protein theory or agricultural and gut-repair questions in rats and GH-deficient mice; endpoints were body length, organ weights and gut morphology, not the recovery or body-composition outcomes the compound is sold against.
- The often-quoted ten-fold potency advantage is a cell-culture figure that depends on how much binding protein is present in the assay; the discoverers state the advantage is only partly retained in vivo, so the number does not transfer to a whole organism.
- No exposure-ranging, comparative or blinded study exists in any species relevant to adult humans, and there is no systematic review or meta-analysis of the compound.
- Identity is unverifiable in unregulated supply: this is a folded, three-disulfide 67-residue protein whose activity depends on correct refolding, and analytical work on the closely related LR3 analogue found a hexahistidine-tagged research construct rather than the stated molecule in a seized black-market vial.
documented safety signals
- The licensed full-length IGF-1 product Increlex is contraindicated in active or suspected neoplasia and its SmPC states there is an increased risk of benign and malignant neoplasia in treated children and adolescents 'since IGF-1 plays a role in the initiation and progression of benign and malignant tumours'; des(1-3)IGF-1 engages the same receptor with less binding-protein restraint.
- The supplier's own validated potency assay for des(1-3)IGF-1 is proliferation of human breast cancer cells, meaning mitogenicity is the property used to certify each lot.
- Hypoglycaemia is a recognised consequence of IGF-1 receptor agonism and appears in the Increlex label; whether the truncated, binding-protein-free variant produces a sharper or shorter glucose effect has never been measured in any species at human-relevant exposure.
- No published human safety data exist for des(1-3)IGF-1 itself. The absence of reported harm reflects the absence of study, not evidence of safety.
identity
| full name | des(1-3) insulin-like growth factor-I — human IGF-I lacking the N-terminal tripeptide Gly-Pro-Glu |
| category | Growth Hormone |
| modality | protein hormone |
| molar mass | 7400 g/mol |
| half-life | No human pharmacokinetic data exist. In the only published clearance study, rats given labelled peptide intravenously cleared des(1-3)IGF-I from plasma roughly 3.8-fold faster than intact IGF-I, with a steady-state volume of distribution about 2.8-fold larger, because the truncated variant essentially fails to associate with the plasma IGF-binding proteins. The direction of that finding is the opposite of the prolonged-action claim usually attached to the compound. |
| sequence | TLCGAELVDALQFVCGDRGFYFNKPTGYGSSSRRAPQTGIVDECCFRSCDLRRLEMYCAPLKPAKSA |
laboratory handling
| storage | Recombinant protein: stored lyophilised at -20 °C to -80 °C, desiccated and protected from light. Reconstituted solution is aliquoted and held at -80 °C, with freeze-thaw cycles avoided because disulfide-linked dimers aggregate readily. Handling information only. |
| solubility | Reconstituted in sterile buffer; carrier protein is commonly added in cell-culture use to reduce adsorption losses. |
| co-studied with | No study has evaluated des(1-3)IGF-1 in combination with anything, in any species. It is routinely sold beside IGF-1 LR3 (graded F in this index) and PEG-MGF, none of which has a single human trial, so any combination rationale is extrapolated from IGF-1 biology rather than derived from data on these molecules. |
Handling information describes laboratory practice for a research reagent. It is not a preparation guide for use in humans.
the receipts
7 citedNovus Biologicals / Bio-Techne · 2025 · official
electronic medicines compendium (emc), UK · 2024 · official
European Medicines Agency · 2007 · official
World Anti-Doping Agency (official list text as published for 2026) · 2026 · official
International Journal of Biochemistry & Cell Biology 28:1085-1087 (Ballard FJ, Wallace JC, Francis GL, Read LC, Tomas FM) · 1996 · review
Journal of Endocrinology 128:197-204 (Ballard FJ, Knowles SE, Walton PE, et al.) · 1991 · preclinical
Journal of Endocrinology 127:401-405 (Gillespie C, Read LC, Bagley CJ, Ballard FJ) · 1990 · preclinical
others in Growth Hormone