Educational reference, not medical advice. This page summarizes information from published research and regulatory filings for educational purposes. It is not a recommendation to use any compound and should not replace guidance from a licensed healthcare provider. Most peptides discussed here are not approved for the uses described.
What it is
IGF-1 DES, formally known as des(1-3) IGF-I, is a naturally occurring 67-amino-acid truncated form of insulin-like growth factor-1 in which the first three N-terminal residues (glycine-proline-glutamate) have been removed. The deletion sits in the part of the IGF-1 molecule that contacts IGF-binding proteins, and the result is a peptide that binds IGFBPs roughly an order of magnitude less tightly than native IGF-1 while retaining nearly full affinity for the type-1 IGF receptor.
The truncated form has been isolated from bovine colostrum, human fetal brain, and porcine uterus, suggesting it is produced endogenously by post-translational proteolytic cleavage. The recombinant version sold as a research reagent is chemically identical to the isolated natural product.
History
Bovine colostrum was the first source from which des(1-3) IGF-I was purified, in work led by the Ballard group at CSIRO in the late 1980s. Gillespie and colleagues showed in 1990 that the truncated form was several-fold more potent than native IGF-1 in stimulating growth in the IGF-1-deficient lit/lit mouse, and Lemmey and colleagues followed up in 1991 with data showing enhanced recovery in rats after intestinal resection.
The mechanistic explanation was clarified by the 1992 Francis et al. paper, which compared IGF-1, Long-R3-IGF-I, and des(1-3) IGF-I head to head and attributed the increased biological potency primarily to escape from IGFBP sequestration rather than to any change in receptor pharmacology.
Like IGF-1 LR3, des(1-3) IGF-I has never been the subject of a Phase II human clinical trial and has not been submitted as a drug application to any major regulator.
Regulatory status
IGF-1 DES has no approved medical use. It is sold globally as a research reagent under not-for-human-use labeling. The World Anti-Doping Agency lists IGF-1 and its analogs under S2 of the Prohibited List, banning use in competitive sport at all times. In the United States the FDA has not approved des(1-3) IGF-I for any indication.
How researchers describe its action
Like native IGF-1, des(1-3) IGF-I binds the type-1 IGF receptor and activates the PI3K/Akt and MAPK pathways. The defining pharmacological feature is its weak interaction with IGFBPs, particularly IGFBP-3, which leaves a higher fraction of administered peptide free and available to engage the receptor. The receptor-level potency of des(1-3) IGF-I is comparable to native IGF-1.
In contrast to IGF-1 LR3, the truncated form does not carry an N-terminal extension that prolongs clearance. The plasma half-life of des(1-3) IGF-I is short, similar to that of free native IGF-1.
Half-life and dosing intervals
The published circulating half-life of des(1-3) IGF-I after subcutaneous administration in rodents is roughly 20 to 30 minutes — much shorter than IGF-1 LR3 but comparable to free native IGF-1. The short half-life and tissue-level pharmacology have led to its use in research contexts where a transient burst of local IGF-1R activation is desired rather than sustained systemic exposure.
There is no established human dose. In rodent studies, doses on the order of 10 to 100 micrograms per kilogram have been used, typically by subcutaneous injection. Observational dosing in non-medical use is typically reported in the 30 to 100 mcg range per administration, with frequent re-dosing reflecting the short half-life — but these patterns have no clinical-trial basis.
Reconstitution example
IGF-1 DES is supplied as a lyophilized powder, most often in 1 mg vials. A common reconstitution is 1 mL of bacteriostatic water added to a 1 mg vial, yielding 1 mg/mL — meaning 0.05 mL on a 1 mL insulin syringe (5 units on a U-100 syringe) contains 50 mcg. Vial's calculator handles the unit-to-mcg conversion automatically when you enter the vial mass and water volume.
What to know
- No human therapeutic data. Almost all efficacy evidence is from rodents and cell culture. No Phase II human trial has been published.
- Short half-life. Unlike IGF-1 LR3, des(1-3) IGF-I is cleared from circulation within 20 to 30 minutes, so plasma exposure from a single injection is brief.
- Banned in sport. WADA prohibits IGF-1 analogs in and out of competition under S2.
- Hypoglycemia risk. Like native IGF-1, des(1-3) IGF-I can lower blood glucose through cross-activation of insulin-receptor signaling, particularly at higher doses.
- Storage. Lyophilized peptide is stable refrigerated and is most stable frozen for long-term storage. Once reconstituted, refrigerate and use within the stability window quoted by the supplier (typically 2 to 4 weeks).
- Long-term safety unknown. Theoretical concerns about sustained IGF-1R activation and cancer risk apply to all IGF-1 analogs; none has been characterized in controlled human studies.
Sources
- 1.Ballard FJ, Wallace JC, Francis GL, Read LC, Tomas FM (1996). Des(1-3)IGF-I: a truncated form of insulin-like growth factor-I. International Journal of Biochemistry & Cell Biology.
- 2.Gillespie C, Read LC, Bagley CJ, Ballard FJ (1990). Enhanced potency of truncated insulin-like growth factor-I (des(1-3)IGF-I) relative to IGF-I in lit/lit mice. Journal of Endocrinology.
- 3.Lemmey AB, Martin AA, Read LC, Tomas FM, Owens PC, Ballard FJ (1991). IGF-I and the truncated analogue des-(1-3) IGF-I enhance growth in rats after gut resection. American Journal of Physiology.
- 4.Francis GL, Ross M, Ballard FJ, Milner SJ, Senn C, McNeil KA, Wallace JC, King R, Wells JR (1992). Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency. Journal of Molecular Endocrinology.
- 5.World Anti-Doping Agency — Prohibited List, S2 Peptide Hormones, Growth Factors, Related Substances and Mimetics.