IGF-1 DES

Overview

IGF-1 DES is a slightly shortened form of insulin-like growth factor 1 (IGF-1), a natural growth signal in the body. It is missing the first three building blocks of IGF-1, which makes it much less likely to be held back by the proteins that normally carry IGF-1 in the blood, so it acts more strongly in cell and animal tests. It has never been approved or tested as a medicine in people, it is banned in sport, and anti-doping scientists report that IGF-1 analogs like it are sold on the black market for bodybuilding.

How it works

Established in cell and animal studies: IGF-1 DES activates the same type 1 IGF receptor as normal IGF-1 ⁵. The missing N-terminal tripeptide (especially the glutamate at position 3) sharply lowers binding to IGF-binding proteins, which normally trap IGF-1 and limit its action. More of the peptide is therefore free to reach the receptor, which is why it looks about 10 times more potent than IGF-1 in cultured cells ¹²⁵. In animals, part of this extra potency remains, with especially strong effects on gut tissue ¹⁶⁷. Proposed: a protease found in many tissues converts IGF-1 to this form, and growth hormone may help control that step through a protease inhibitor; this comes from rat and cell work ⁸.

What research shows

• Cell studies: in rat L6 muscle cells, IGF-1 DES stimulated protein synthesis and cut protein breakdown more strongly than IGF-1 (about 10-fold), and was at least as strong for DNA synthesis ². In several cell types it competed for the type 1 IGF receptor more strongly than IGF-1, which the authors linked to weak binding to a cell-made binding protein ⁵.
• Rats after removal of about 80% of the small intestine (animal study, 7 days): IGF-1 DES at 0.96 mg/kg/day gave weight gain (20.8 g vs 14.0 g on vehicle) and nitrogen balance similar to a 2.5-fold higher dose of IGF-1; thymus weight also rose ⁶.
• Steroid (dexamethasone)-treated rats (animal studies): IGF-1 DES and LR3 IGF-1 were about 2.5-fold more potent than IGF-1 at reversing muscle-wasting effects, and both increased gut weight; IGF-1 alone raised gut weight by up to 60% at its highest dose, and the variants had similar effects but were several-fold more potent ⁷⁹.
• Pigs and marmoset monkeys (animal study): IGF-1 DES lowered blood sugar more strongly and for longer than IGF-1; it was the most potent of the variants tested ¹².
• Transgenic mice made to over-produce IGF-1 DES in the breast (animal study): 53% developed breast adenocarcinomas by 23 months, and tumor rates were 2–3 times higher than in normal mice ¹³.
• Anti-doping research: methods can detect IGF-1 DES in human plasma; after a single injection in rats, unchanged IGF-1 DES was detectable for up to 24 hours. Black-market IGF-1 analog products showed many signs of poor quality (oxidized peptide) ¹⁰¹¹.
• No human clinical trials were found ¹¹¹.

Doses studied in people

No published human dosing data exist; the peptide has never been tested in a human trial, and doses circulating online are not based on clinical studies.

Read this first: these are the amounts given to participants in published studies or written on official prescribing labels, reported for reference. They are not recommendations. Trial doses were chosen for specific patients under medical supervision, and a dose that is safe in one person can be harmful in another.

Vial math

Many research vials hold 5 or 10 mg of powder. This table shows how much ends up in each mark on a U-100 insulin syringe for common amounts of added liquid. It is arithmetic only, not a dose.

More sizes: all vial sizes · How this works: Syringes and units · Reconstitution guide.

Safety

• No human safety data: IGF-1 DES has never been approved for human use or studied in human trials ¹¹.
• Low blood sugar (animal study): in pigs and marmoset monkeys it lowered blood glucose more strongly and for longer than IGF-1 ¹².
• Cancer signal (animal study): mice engineered to over-produce IGF-1 DES in breast tissue developed more breast tumors, and it reduced normal cell death (apoptosis) in breast tissue ¹³. Human relevance is unknown.
• Product quality: anti-doping researchers found abundant oxidized, lower-quality peptide in black-market IGF-1 analog products ¹¹.
• Unknown long-term safety.

Report side effects of any drug or product to the FDA through MedWatch. For a possible poisoning in the US, call Poison Control at 1-800-222-1222.

Legal status

FDA

Not FDA-approved. IGF-1 analogs such as IGF-1 DES have never been approved for use in humans ¹¹.

Compounding

No FDA 503A/503B listing or compounding action for IGF-1 DES was found in the sources reviewed.

Sports (WADA)

Prohibited at all times (in and out of competition) under S2, which names insulin-like growth factor 1 (IGF-1) and its analogues; S2 substances are non-Specified (2026 List text) ¹⁴. Anti-doping labs have developed tests that specifically target IGF-1 DES ¹⁰¹¹.

Other

Described in anti-doping literature as sold on the black market for bodybuilding ¹¹.

Rules change often. See Legal status of peptides for how these categories work.

History

A truncated variant of IGF-1 was described in 1986 by Sara, Jörnvall and colleagues, who isolated it from human fetal brain and then adult brain ³⁴. In 1988 an Australian group purified it from bovine colostrum, showed it lacks the Gly-Pro-Glu tripeptide, and found it about 10 times more active than IGF-1 in muscle cells ². Through the early 1990s Adelaide researchers (CSIRO and the Child Health Research Institute) tested it in rats with gut surgery, steroid-induced muscle loss and diabetes ⁶⁷⁹. A 1996 review noted that its clinical uses had not been evaluated ¹. Later work focused on detecting it in anti-doping tests ¹⁰¹¹.

Common questions

Related compounds

Sources

1. Ballard FJ et al. Des(1-3)IGF-I: a truncated form of insulin-like growth factor-I. Int J Biochem Cell Biol 1996 (PMID 8930132) PubMed review
2. Francis GL et al. Insulin-like growth factors 1 and 2 in bovine colostrum: sequences and biological activities compared with those of a potent truncated form. Biochem J 1988 (PMID 3390164) Journal
3. Sara VR et al. Characterization of somatomedins from human fetal brain: identification of a variant form of insulin-like growth factor I. PNAS 1986 (PMID 3460078) Journal
4. Carlsson-Skwirut C et al. Isolation and characterization of variant IGF-1 as well as IGF-2 from adult human brain. FEBS Lett 1986 (PMID 3709807) Journal
5. Ballard FJ et al. Specific binding of insulin-like growth factors 1 and 2 to the type 1 and type 2 receptors respectively. Biochem J 1988 (PMID 2965574) Journal
6. Lemmey AB et al. IGF-I and the truncated analogue des-(1-3)IGF-I enhance growth in rats after gut resection. Am J Physiol 1991 (PMID 1996625) Journal
7. Read LC et al. Insulin-like growth factor-I and its N-terminal modified analogues induce marked gut growth in dexamethasone-treated rats. J Endocrinol 1992 (PMID 1613443) Journal
8. Maake C et al. The growth hormone dependent serine protease inhibitor, Spi 2.1 inhibits the des (1-3) insulin-like growth factor-I generating protease. Endocrinology 1997 (PMID 9389551) Journal
9. Tomas FM et al. Insulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated rats. Biochem J 1992 (PMID 1371669) Journal
10. Thomas A et al. Determination of LongR3-IGF-I, R3-IGF-I, Des1-3 IGF-I and their metabolites in human plasma samples by means of LC-MS. Growth Horm IGF Res 2017 (PMID 28668757) Journal
11. Mongongu C et al. Detection of LongR3-IGF-I, Des(1-3)-IGF-I, and R3-IGF-I using immunopurification and high resolution mass spectrometry for antidoping purposes. Drug Test Anal 2021 (PMID 33587816) Journal
12. Tomas FM et al. IGF-I variants which bind poorly to IGF-binding proteins show more potent and prolonged hypoglycaemic action than native IGF-I in pigs and marmoset monkeys. J Endocrinol 1997 (PMID 9415072) Journal
13. Hadsell DL et al. Cooperative interaction between mutant p53 and des(1-3)IGF-I accelerates mammary tumorigenesis. Oncogene 2000 (PMID 10702797) Journal
14. German Sport University Cologne: S2 Peptide hormones, growth factors, related substances and mimetics (WADA Prohibited List text effective 1 January 2026) Regulatory
15. UniProt P05019: Insulin-like growth factor 1 (human), mature chain residues 49-118 Database