IGF-DES

IGF-DES (des(1-3) IGF-1) is a truncated analogue of insulin-like growth factor-1 designed to alter receptor interactions and local tissue activity.

It is primarily encountered in experimental and performance-related discussions, not routine clinical endocrinology.

Removal of the first three amino acids reduces binding to IGF-binding proteins, potentially increasing local availability at IGF-1 receptors in certain tissues.

IGF-DES has been explored conceptually for localized growth or repair, but it is not an approved therapy for these indications.

Non-regulated use is associated with uncertainty around benefits and risks.

IGF-DES — des(1-3) IGF-1 — falls under sub-section S2.3 of the WADA Prohibited List, "Growth factors and growth factor modulators," whose second bullet reads "Insulin-like growth factor 1 (IGF-1, mecasermin) and its analogues." A peptide defined by the deletion of the first three residues of IGF-1 is an analogue of IGF-1 in the plainest sense of the word. The literature groups it with its siblings for exactly the reason it is used: "LongR3 IGF-I, Des1-3 IGF-I and Arg3 IGF-I" were engineered for "their lower affinity for the IGFBPs, while still retaining unaffected affinity for the IGF-I receptor" (Adams et al., Am J Rhinol 2006). S2.3 also closes with a functional catch-all covering "other growth factors or growth factor modulators affecting muscle, tendon or ligament protein synthesis/degradation, vascularisation, energy utilization, regenerative capacity or fibre type switching," so there is no structural argument available here. All S2 substances are non-Specified Substances, and the default first-violation sanction is four years.

Anti-doping chemists state the status without qualification: "Insulin-like growth factor-I (IGF-I) and its analogs LongR3-IGF-I, Des(1-3)-IGF-I, and R3-IGF-I are prohibited substances in sport. Although they were never approved for use in humans, they are readily available as black market products for bodybuilding and can be used to enhance physical performance" (Mongongu et al., Drug Test Anal 2021).

Detection: the truncation cuts both ways. Removing three amino acids is what frees des(1-3) IGF-1 from the binding proteins — and it is also what makes it trivially distinguishable from endogenous IGF-1 by mass spectrometry, since the molecule differs from the native hormone by a defined mass. Validated methods target the analogue directly by immunopurification followed by high-resolution mass spectrometry rather than by watching total IGF-1 concentrations (Thomas et al., Growth Horm IGF Res 2017).

In the rat administration study, DES was the most persistent of the three analogues in unchanged form: after a single 100 μg/kg intramuscular dose, "unchanged Des(1-3)-IGF-I and R3-IGF-I were detected until 24 h after administration," while LongR3-IGF-I "disappeared rapidly after 4 h" (Mongongu 2021). The authors also found the same degradation products after incubating the analogues in human whole blood, "suggesting that observations in rats may be extrapolated to humans and that the validated method may be applicable to antidoping testing." The short in-tissue half-life that makes DES attractive as a "local" agent in gray-market discussion does not translate into a short analytical window.

Enforcement does not require an analytical finding at all. Vahe Aivazian, a masters cyclist, accepted a four-year USADA sanction beginning 7 April 2021 for possessing and using ten prohibited substances including IGF-1 (USADA sanction announcement). Possession and use are independent anti-doping rule violations.

Formal safety data for IGF-DES in humans are limited.

IGF-1 DES (1-3) is a truncated, short-acting analogue (half-life ~20-30 mins) used for site-specific growth.

This peptide is used to target specific muscle groups ("site enhancement") rather than systemic growth.

IGF-DES is supplied as a lyophilized powder for reconstitution and sold as a research reagent, so identity, purity, and actual peptide content are unverified. Unlike engineered constructs, des(1-3)IGF-I occurs naturally and has been isolated from bovine colostrum, human brain, and porcine uterus, probably as a post-translational cleavage product of IGF-I (PMID 8930132).

The combinations discussed in performance contexts each stack onto the same hazard. DES ranked as the most potent hypoglycemic agent among the IGF variants compared in pigs and marmosets (PMID 9415072), so pairing it with insulin compounds the risk that dominates its profile. Pairing it with IGF-1 LR3 combines two binding-resistant analogs engineered toward opposite durations — brief and prolonged — acting on the same receptor. And somatropin raises endogenous IGF-1 on top of whatever analog is already present.

Evidence consists mainly of preclinical work and limited quasi-clinical use; large randomized trials are lacking.

For deeper dives on this peptide, see:

• IGF-DES benefits and areas of interest
• IGF-DES side effects and safety context
• IGF-DES dosing concepts (educational)
• IGF-DES research and evidence overview

What does "DES(1-3)" mean? It is IGF-I with the N-terminal tripeptide Gly-Pro-Glu deleted. That deletion removes the glutamate at position 3, and the absence of that single residue is what causes the much reduced binding to IGF-binding proteins (PMID 8930132).

Is it really 10 times more potent than IGF-1? In cultured cells, yes — the foundational review describes des(1-3)IGF-I as generally about 10-fold more potent than IGF-I at stimulating hypertrophy and proliferation of cultured cells. In whole animals that increased potency is retained only in part, with selective anabolic effects most evident in gut tissues.

Has it been tested in people? No. The same review stated that clinical opportunities for des(1-3)IGF-I "have not yet been evaluated," and no controlled human trials have been published since. It is not approved in any jurisdiction and is sold as a research chemical.

Does its short half-life make it safer? The animal data argue otherwise. DES ranked highest of the IGF variants tested for hypoglycemic potency, and the binding-resistant variants as a class produced roughly 4- to 8-fold greater cumulative glucose suppression than IGF-I over four hours — with the prolonged suppression not proportional to the depth of the drop (PMID 9415072).

Is there an approved IGF-1 medicine to compare it to? Yes: mecasermin (Increlex), full-length recombinant IGF-1, indicated only for growth failure in children two and older with severe primary IGF-1 deficiency or GH gene deletion with neutralizing antibodies to GH. Its label carries a hypoglycemic-seizure warning and requires dosing within ±20 minutes of a meal, with the dose withheld if the patient cannot eat (DailyMed).