IGF-1 Des: A Literature Course in Six Modules

This page is for educational purposes only and is not medical advice; consult a licensed physician about any health decision or compound. The course below summarises what published studies reported about IGF-1 Des. It does not describe protocols, and it does not claim benefits.

About this course

The six modules move from definition to mechanism, then to reported outcomes, published adverse findings, pharmacokinetic data, and regulatory status. Every module closes with the limits of the evidence, because the literature on this molecule is small, mostly preclinical, and heavily weighted toward cell and tissue models rather than human trials.

Module 1: What IGF-1 Des Is and How It Has Been Studied

IGF-1 Des is an informal name for des(1-3)IGF-I, an analogue of insulin-like growth factor I that lacks the first three amino acids at the N-terminus of the parent protein. It belongs to the insulin/IGF superfamily of peptide growth factors, which also includes IGF-II and insulin itself.

Analytical chemistry has been one of the most consistent sources of published information on this molecule. A 2021 analytical study described immunopurification combined with high-resolution mass spectrometry to detect LongR₃-IGF-I, Des(1-3)-IGF-I and R₃-IGF-I for anti-doping purposes, treating the three as a family of IGF-I analogues that require distinguishing from endogenous IGF-I (PMID 33587816). A 2024 method paper extended chromatographic-mass spectrometric analysis to peptidic analytes in the 2–10 kDa range in doping control urine samples (PMID 38197510), and a companion paper applied a comparable approach to doping control blood samples (PMID 38716080).

Forms encountered in the literature

• Des(1-3)IGF-I — the truncated analogue that is the subject of this course.
• R₃-IGF-I and LongR₃-IGF-I — separate engineered IGF-I analogues that the 2021 anti-doping method grouped alongside des(1-3)IGF-I for detection purposes (PMID 33587816).
• Native IGF-I — the reference molecule used as comparator in most of the tissue studies cited below.

Limits of the evidence in Module 1

The verified literature summarised here is dominated by in vitro work, animal models and analytical method development. None of the cited papers is a controlled human clinical trial of des(1-3)IGF-I, and the anti-doping methods establish only that the analogues can be detected, not how they behave in people who receive them.

Module 2: Mechanism as Described in the Literature

Published mechanistic descriptions of IGF-I and its truncated analogue centre on two things: the type 1 IGF receptor and the family of IGF binding proteins (IGFBPs).

Receptor signalling

In a diabetic rat model, researchers reported that des(1-3)IGF-1 treatment normalised type 1 IGF receptor and phospho-Akt (Thr 308) immunoreactivity in predegenerative retina (PMID 12745670), placing the analogue within the receptor-tyrosine-kinase/Akt signalling axis that is standard for IGF-I biology. In neural tissue, a 2005 electrophysiology study functionally characterised des-IGF-1 action at excitatory synapses in the CA1 region of rat hippocampus, examining synaptic transmission rather than growth endpoints (PMID 15985695).

Binding-protein interactions

The rationale most often given for studying a truncated IGF-I is altered interaction with binding proteins. Work in human retinal endothelial cells reported that IGFBPs modulated IGF-I- and high-glucose-controlled growth of those cells, demonstrating that the binding-protein layer materially changes what IGF signalling does in a given tissue (PMID 11691647).

Tissue access

Mechanism also depends on whether the molecule reaches its receptor. A 2003 study measured transport and binding of insulin-like growth factor I through articular cartilage, characterising how the growth factor moved through a dense extracellular matrix (PMID 12801514), and an in vivo and in situ study examined interactions of IGF-1 with the blood–brain barrier (PMID 11025411).

Limits of the evidence in Module 2

Several of the mechanistic papers studied native IGF-I rather than the truncated analogue, so their conclusions cannot be transferred to des(1-3)IGF-I without assumption. The hippocampal and retinal studies used specific tissue preparations under defined conditions; they describe what happened in those preparations and not what happens in an intact human.

Module 3: Reported Outcomes by Study

The table below lists what the cited studies used as models and what they reported. No study in this set measured body composition, athletic performance or recovery in humans.

Reading the outcome set

Two patterns stand out. First, the reported effects are proliferative or signalling effects in tissue systems: growth of prostate stromal cells (PMID 12573816), growth of retinal endothelial cells under binding-protein control (PMID 11691647), and receptor/Akt marker normalisation in diabetic retina (PMID 12745670). Second, the one whole-animal oncology model reported acceleration rather than improvement, with mutant p53 and des(1-3)IGF-I acting cooperatively on mammary tumorigenesis (PMID 10702797).

Limits of the evidence in Module 3

These are not benefit findings. A marker normalising in a rodent retina is a biochemical observation, not a demonstrated clinical outcome, and a cell line proliferating in culture says nothing about safety or usefulness in a person. The studies used different species, different exposure conditions and different endpoints, so they cannot be pooled into a single effect estimate.

Module 4: IGF-1 Des Side Effects: What Studies Report

No study in this verified set was designed as a human safety trial, so there is no published adverse-event table of the kind produced by a Phase I programme. What exists are preclinical findings with recognised safety implications.

Tumour promotion in an animal model

The clearest published adverse signal came from a mouse mammary model in which researchers reported that mutant p53 and des(1-3)IGF-I interacted cooperatively to accelerate mammary tumorigenesis (PMID 10702797). This is a direct observation that the analogue accelerated tumour development in a genetically susceptible model.

Proliferation of non-target tissue

In human prostate tissue culture, the study reported that des(1-3)IGF-I stimulated growth of stromal BPH cells, an effect that a vitamin D3 analogue inhibited (PMID 12573816). Stimulated proliferation of benign prostatic stroma is a biologically relevant concern rather than a desired outcome.

Vascular and retinal tissue

Growth of human retinal endothelial cells was reported to be controlled by IGF-I together with high glucose and modulated by IGFBPs (PMID 11691647), which situates IGF signalling within the biology of proliferative retinal disease. A separate rat study reported changes to type 1 IGF receptor and phospho-Akt immunoreactivity in diabetic retina after des(1-3)IGF-1 treatment (PMID 12745670), showing that retinal tissue is responsive to the analogue in both directions of interpretation.

Limits of the evidence in Module 4

Absence of reported adverse events in cell studies is not evidence of safety; those studies did not look for adverse events. There are no published data here on hypoglycaemia, immunogenicity, injection-site reactions, organ toxicity or long-term human exposure for this analogue. The oncology finding came from a model with an existing p53 mutation and cannot be extrapolated quantitatively to other settings.

Module 5: Pharmacokinetics Where Data Exist

Human pharmacokinetic parameters — half-life, bioavailability, clearance — were not reported in any paper in this verified set. What the literature does provide is transport and detection data.

Barrier and matrix transport

An in vivo and in situ study examined interactions of IGF-1 with the blood–brain barrier, addressing whether and how the growth factor crosses into the central nervous system (PMID 11025411). In connective tissue, researchers measured transport and binding of IGF-I through articular cartilage, a matrix in which binding to resident proteins slows and shapes penetration (PMID 12801514).

Routes of administration studied

Delivery route research relevant to protein cargoes generally includes a 2022 report describing efficient transdermal delivery of functional protein cargoes using the hydrophobic peptide MTD 1067 (PMID 35760980). That work concerned a delivery technology rather than a clinical regimen for any IGF analogue.

Detectability as an indirect exposure measure

Anti-doping analytical work supplies the closest thing to human exposure data. The 2021 method used immunopurification with high-resolution mass spectrometry to detect Des(1-3)-IGF-I and related analogues (PMID 33587816); later method papers targeted peptidic analytes of 2–10 kDa in doping control urine (PMID 38197510) and in doping control blood samples (PMID 38716080).

Limits of the evidence in Module 5

Detection windows are analytical performance characteristics, not pharmacokinetic parameters. No cited study reported plasma concentration–time curves, dose proportionality or tissue distribution for des(1-3)IGF-I in humans, and the cartilage and blood–brain barrier work used native IGF-I.

Module 6: Regulatory Status

Stated factually: des(1-3)IGF-I is not an approved medicine in the United States, the European Union or other major jurisdictions. It is supplied by chemical and biotech suppliers as a research-use-only (RUO) material, a designation that means the substance is intended for laboratory investigation and is not labelled, tested or released for human administration. RUO products are not required to meet the manufacturing, purity and stability standards applied to medicinal products.

Recombinant human IGF-1 exists as an approved medicinal product in some jurisdictions for specific rare indications; that approval covers the full-length recombinant molecule and its labelled indication, not truncated analogues such as des(1-3)IGF-I, R₃-IGF-I or LongR₃-IGF-I. In US compounding law, an active ingredient generally must appear on an FDA bulk drug substances list or be a component of an approved drug to be eligible for compounding; peptide analogues without that status fall outside those pathways.

In sport, IGF-1 analogues are treated as prohibited substances, which is why dedicated detection methods were developed: the 2021 immunopurification–mass spectrometry method was described explicitly for antidoping purposes (PMID 33587816), and subsequent methods extended screening of 2–10 kDa peptidic drugs into routine urine (PMID 38197510) and blood matrices (PMID 38716080).

Limits of the evidence in Module 6

Regulatory classifications differ by country and change over time, and this summary is general information rather than legal advice. Nothing in the analytical literature speaks to the legality of possession or use in any particular jurisdiction.

What the Studies Did Not Test

Reading across all six modules, the gaps are larger than the findings:

• No human efficacy trials. No cited study enrolled human participants to measure strength, lean mass, injury recovery, wound healing or cognition.
• No human dosing data. No dose, frequency or duration for humans appears in the verified literature, which is why none is stated anywhere on this page.
• No long-term safety follow-up. The tumour-acceleration finding came from a short-horizon mouse model with mutant p53 (PMID 10702797); no study tracked long-term outcomes after exposure.
• No head-to-head comparison with native IGF-I in humans. Comparisons in the cited work were made in cell and tissue systems, such as binding-protein-modulated growth of retinal endothelial cells (PMID 11691647).
• No product-quality data. Nothing in this literature characterises the purity or identity of materials sold outside regulated supply chains.

Readers interested in IGF biology can follow the same studies forward: the mechanistic axis of receptor and Akt signalling (PMID 12745670), tissue access questions raised by barrier and matrix transport work (PMID 11025411), and the analytical chemistry that determines whether these analogues can be identified in biological samples (PMID 33587816).

References

• Interactions of IGF-1 with the blood-brain barrier in vivo and in situ (Neuroendocrinology, 2000)
• Detection of LongR(3)-IGF-I, Des(1-3)-IGF-I, and R(3)-IGF-I using immunopurification and high resolution mass spectrometry for antidoping purposes (Drug Testing and Analysis, 2021)
• Efficient transdermal delivery of functional protein cargoes by a hydrophobic peptide MTD 1067 (Scientific Reports, 2022)
• IGFBPs modulate IGF-I- and high glucose-controlled growth of human retinal endothelial cells (The Journal of Endocrinology, 2001)
• Chromatographic-mass spectrometric analysis of peptidic analytes (2-10 kDa) in doping control urine samples (Journal of Mass Spectrometry, 2024)
• Transport and binding of insulin-like growth factor I through articular cartilage (Archives of Biochemistry and Biophysics, 2003)
• Functional characterization of des-IGF-1 action at excitatory synapses in the CA1 region of rat hippocampus (Journal of Neurophysiology, 2005)
• Des (1-3) IGF-I-stimulated growth of human stromal BPH cells is inhibited by a vitamin D3 analogue (Molecular and Cellular Endocrinology, 2002)
• Des(1-3)IGF-1 treatment normalizes type 1 IGF receptor and phospho-Akt (Thr 308) immunoreactivity in predegenerative retina of diabetic rats (International Journal of Experimental Diabesity Research, 2003)
• Cooperative interaction between mutant p53 and des(1-3)IGF-I accelerates mammary tumorigenesis (Oncogene, 2000)
• Probing for peptidic drugs (2-10 kDa) in doping control blood samples (Analytical Science Advances, 2022)
• Response of the porcine MYH4-promoter and MYH4-expressing myotubes to known anabolic and catabolic agents in vitro (Biochemistry and Biophysics Reports, 2021)