IGF-1 DES is native insulin-like growth factor-1 with the first three amino acids, Gly-Pro-Glu, cut off. Catalogs sell it as a local anabolic analog, and the Adelaide biochemistry is real: drop glutamate-3 and the peptide stops hiding on IGF-binding proteins. Human trials of this truncated form do not exist.

TL;DR

  • des(1-3)IGF-I is a 67-residue IGF-1 found in bovine colostrum, human brain, and porcine uterus, almost certainly from cleavage of the 70-residue hormone.
  • Glu-3 is the IGFBP contact. Lose it and cultured myoblasts see about 10-fold more hypertrophy and proliferation at the same mass of peptide.
  • In diabetic and dexamethasone-treated rats, DES raised nitrogen retention and muscle protein synthesis. It did not fix diabetic glucosuria the way insulin did.
  • LR3-IGF-I is a different analog (13-residue N-terminal extension plus Arg-3). Both dodge IGFBPs. Only LR3 was built as a long recombinant fusion.
  • There is no FDA-approved DES product. Increlex is full-length mecasermin. WADA lists IGF-1 and its analogues under S2.3.

Educational only. Not medical advice, not a protocol, and not a reason to treat a research vial as Increlex.

What is IGF-1 DES actually?

Native human IGF-1 is 70 amino acids. DES is that sequence minus the N-terminal tripeptide Gly-Pro-Glu.

Ballard’s 1996 minireview is the clean map. The truncated protein was isolated from bovine colostrum, human brain, and porcine uterus, probably as a clip of IGF-1 rather than a separate gene (Ballard et al., 1996).

Fitness boards call it IGF-1 DES, DES(1-3), or “the local one.” The chemistry name is des(1-3)IGF-I. For the size primer, see Peptides 101.

Why does cutting three residues change potency?

IGF-1 does not roam free. Most of it is parked on insulin-like growth factor binding proteins (IGFBPs).

Bagley’s group synthesized IGF-1 missing one through five N-terminal residues and ran them on rat L6 myoblasts. Half-maximal protein synthesis sat at 13 ng/ml for IGF-1 and 1.5 ng/ml for des(1-3)IGF-1.

Receptor competition barely moved. Binding-protein competition collapsed more than 60-fold for the three shortest peptides (Bagley et al., 1989).

The glutamate at position 3 is the switch. des(1) and des(1-2) behaved like full-length IGF-1. des(1-3) did not. That is reduced IGFBP sequestration, not a magic receptor upgrade.

The IGF-1 receptor still runs the usual muscle cascade, PI3K, Akt, then mTORC1 (Yoshida and Delafontaine, 2020). DES uses that receptor. It just arrives with less of the peptide locked up.

What did the animal studies actually measure?

The Adelaide group then put the truncated peptide into whole animals. These are infusion and injection studies, not gym protocols.

Study Model Comparison Main finding
Bagley 1989 Rat L6 myoblasts DES vs IGF-1 About 10-fold more potent on protein synthesis
Gillespie 1990 GH-deficient lit/lit mice 3 or 30 micrograms/day 3 micrograms DES beat 3 micrograms IGF-1 on length and organ weights
Tomas 1991 Streptozotocin-diabetic rats 7-day infusion DES at 1.08 mg/kg per day matched a 2.5-fold higher IGF-1 dose on nitrogen retention
Tomas 1992 Dexamethasone-catabolic rats DES and LR3 vs IGF-1 Both variants about 2.5-fold more potent than IGF-1
Tomas 1997 Pigs and marmosets Acute bolus DES 2- to 3-fold more hypoglycaemic than IGF-1, with a longer glucose dip

In diabetic rats, IGF peptides raised weight and nitrogen retention without clearing the glucosuria insulin cleared. Muscle protein synthesis went up. 3-methylhistidine excretion, a breakdown marker, did not fall the way it did on insulin (Tomas et al., 1991).

The dexamethasone paper puts DES next to LR3-IGF-I. Both bound IGFBPs poorly and were about 2.5-fold more potent than IGF-1, even though LR3 bound the type 1 receptor about 3-fold less well (Tomas et al., 1992). GH-deficient lit/lit mice showed the same direction: equal-mass DES beat IGF-1 (Gillespie et al., 1990).

Tomas later gave boluses to pigs and marmosets. Variants that skip IGFBPs dropped plasma glucose harder and longer than native IGF-1, even though they cleared plasma faster (Tomas et al., 1997).

That last result is a safety flag, not a selling point. IGF-1 receptor agonists can drop blood glucose. Catalog marketing that calls DES “local only” is skipping the pig and marmoset data.

How is DES different from IGF-1 LR3?

Both were built, or found, to dodge IGFBPs. They are not the same molecule.

DES is a 67-residue clip of the natural sequence.

LR3 adds a 13-amino-acid N-terminal extension and swaps Glu-3 for arginine. Our IGF-1 LR3 article covers that engineering.

In the dexamethasone rats they landed in the same potency neighborhood versus IGF-1. That does not make them interchangeable, and it does not create human dose data.

Forum shorthand says DES is “short and local” and LR3 is “long and systemic.” The papers show both can act systemically in animals. DES has no published human pharmacokinetic trial.

Is a research vial the same as Increlex?

No.

Increlex (mecasermin) is recombinant full-length human IGF-1. FDA approved it for growth failure in children with severe primary IGF-1 deficiency, not for body composition in healthy adults (FDA Increlex label).

DES is not mecasermin. There is no FDA-approved des(1-3)IGF-I drug. Licensed peptide products live in pharmacy and telehealth channels, which is what the provider directory and price index compare.

WADA lists insulin-like growth factor-1 (IGF-1, mecasermin) and its analogues under S2.3, prohibited at all times. A truncated analog is still an analog (WADA Prohibited List).

A catalog vial is a research chemical. Identity, salt, and endotoxin are COA questions.

Handling education lives on the reconstitution guide and the calculator. There are no randomized trials of IGF-1 DES in humans.

Bottom line: IGF-1 DES is a real truncated IGF-1 with cleaner IGFBP escape and stronger cell and animal potency than the full-length hormone. It is not Increlex, it is not LR3, and a research vial is not a localized hypertrophy drug.

Educational only. Not medical advice. Not a recommendation to use IGF-1 DES, IGF-1 LR3, mecasermin, or any research-grade growth factor analog.