Muscle & Performance
IGF-1 DES (1-3)
aka IGF-1 DES · igf-1 des · igf1 des · igf 1 des · des igf · des-igf-1 · igf-1 des 1-3 · igf-1 des (1-3) · des(1-3)IGF-1 · des(1-3)IGF-I · des(1-3) IGF-1 · DES 1-3 · truncated IGF-1 · IGF DES · DES IGF-1
Grade
A shortened, stronger form of the body's growth factor IGF-1, sold online for 'local' muscle growth, which has never been tested in a single human trial.
- Class
- Truncated variant of insulin-like growth factor 1 (IGF-1): the 70-amino-acid hormone with its first three amino acids (Gly-Pro-Glu) removed, leaving 67. A small protein / IGF-1 receptor agonist; a natural form exists in the body
- Evidence
- Grade D · Animal data only
- Sport / WADA
- Prohibited at all times (in and out of competition). The 2026 WADA Prohibited List names 'Insulin-like growth factor 1 (IGF-1, mecasermin) and its analogues' under S2.3 (Growth factors and growth factor modulators), and anti-doping labs have published methods specifically to detect des(1-3)-IGF-I.
- Last reviewed
- 2026-10
Grade D · Animal data only
Why this grade
IGF-1 DES has never been tested in a human trial for any purpose. Nothing is registered on ClinicalTrials.gov, and an anti-doping paper (Mongongu 2021) notes it was never approved for use in humans. What is known comes from cells in lab dishes and from animals: rats, pigs and marmoset monkeys. Those studies show it is a strong, well-understood growth signal, roughly ten times stronger than normal IGF-1 in cell culture, and that it lowers blood sugar more strongly and for longer than normal IGF-1 in pigs and monkeys. The licensed IGF-1 medicine (mecasermin) is a different, full-length molecule for a rare childhood condition, so its human data do not transfer. For the muscle-building use people buy it for, there are no human data at all.
What is it?
Why people buy it
Bodybuilders buy it to grow muscle, often injected into one muscle. It is a shortened, stronger form of IGF-1, a natural growth signal.
What we actually know
- •Your body makes this form too. It was found in the brain, in cow first milk and in other tissues.
- •In lab dishes, it is about ten times stronger than normal IGF-1 at making cells grow.
- •In rats it boosted growth. In pigs and monkeys it lowered blood sugar more strongly than normal IGF-1.
- •It has never been tested in people. It is not a licensed medicine in the UK.
What might happen
- •Nobody knows if it builds muscle in people. There are no studies in people at all.
- •Low blood sugar is a real risk. In pigs and monkeys this form caused the biggest drop of all the IGF-1 types tested.
- •Sellers say it only works where you inject it. There is no proof of this. In animals, it acted on the whole body.
- •Long-term high IGF-1 might help cancers grow. This is a theory, not proven.
- •It is sold online as 'not for human use'. Lab tests on online products have found poor-quality, damaged product.
- •It is banned in sport at all times. Tested athletes can fail a drugs test.
Bottom line
A strong growth signal studied only in lab dishes and animals. In people, it is completely untested.
Know someone taking this?
Send on WhatsAppIt is like taking the safety catch off a power tool. The tool is the same, but nothing now holds it back, so it runs harder and longer. That has been shown on the workbench with cells and in animals. Nobody has tested what it does in a person's hands.
How is it meant to work?
Binds and activates the IGF-1 receptor (a receptor tyrosine kinase), switching on growth and survival signalling that drives cell proliferation and protein synthesis. Because the first three amino acids are missing, including the glutamate at position 3, it binds the IGF binding proteins very weakly. Normally those carrier proteins hold most IGF-1 in an inactive reserve. Escaping them leaves more of the molecule free and active, which explains its greater potency in cell culture. Like IGF-1 it also lowers blood sugar, and in animals this effect was stronger and longer-lasting than with native IGF-1.
What's it studied for?
Research contexts. Not proven uses, and not recommendations.
Does the human evidence stack up?
None. No human trial of IGF-1 DES has been registered or published, for muscle growth or any other use. A 1996 review by the group that studied it most said its clinical uses had not been evaluated, and that is still the case. Humans make it naturally (it was isolated from human brain), but that tells us nothing about injecting it. The only human-related research is anti-doping work on detecting it. Claims of 'local' muscle growth have no human evidence behind them.
What could go wrong?
- !No human safety or efficacy data of any kind.
- !Hypoglycaemia: in pigs and marmosets it was the most potent blood-sugar-lowering IGF-1 variant tested, ahead of IGF-1 LR3, and the variants as a group lowered blood sugar for longer than native IGF-1.
- !The 'site-specific, local only' sales claim has no evidence behind it; in animals its effects, such as lowering blood sugar, were body-wide.
- !Theoretical cancer concern: long-term, above-normal IGF-1 receptor signalling is pro-growth and pro-survival; this has not been studied for IGF-1 DES.
- !Problems seen with the licensed IGF-1 medicine (mecasermin), such as raised pressure inside the skull and lymphoid tissue overgrowth, may apply, though this is extrapolation.
- !Grey-market quality: anti-doping labs found oxidised, lower-quality peptide in black-market products; vials are unregulated and may be degraded, mislabelled or non-sterile.
- !Banned at all times in sport by WADA.
Is it legal in the UK?
IGF-1 DES is not a licensed medicine in the UK; the MHRA has authorised no product containing it. The only licensed IGF-1 medicine is mecasermin (Increlex), native full-length IGF-1, a prescription-only medicine for severe primary IGF-1 deficiency in children, and a different molecule. IGF-1 and its variants are not listed as controlled drugs under the Misuse of Drugs Act 1971 (the Class C hormone list covers somatropin and related growth hormones, not IGF-1). IGF-1 DES is sold online as an unlicensed 'research chemical, not for human consumption'; supplying or marketing it for human use would breach the Human Medicines Regulations 2012.
Sources
- 01Des(1-3)IGF-I: a truncated form of insulin-like growth factor-I — Ballard FJ, Wallace JC, Francis GL, Read LC, Tomas FM, International Journal of Biochemistry & Cell Biology (1996)
Review: isolated from bovine colostrum, human brain and porcine uterus; about 10-fold more potent than IGF-I in cultured cells due to reduced IGF binding protein binding; clinical uses not evaluated.
- 02IGF-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 — Tomas FM, Walton PE, Dunshea FR, Ballard FJ, Journal of Endocrinology (1997)
Animal study. des(1-3)IGF-I was the most potent glucose-lowering variant tested (ahead of LR3IGF-I), with longer-lasting hypoglycaemia than native IGF-I.
- 03Insulin-like growth factor-I and more potent variants restore growth of diabetic rats without inducing all characteristic insulin effects — Tomas FM, Knowles SE, Owens PC, et al., Biochemical Journal (1993)
Rat study: des(1-3)IGF-I and LR3-IGF-I were 2.5-3 times more potent than IGF-I at restoring growth. Not human.
- 04Detection of LongR3-IGF-I, Des(1-3)-IGF-I, and R3-IGF-I using immunopurification and high resolution mass spectrometry for antidoping purposes — Mongongu C, Coudoré F, Domergue V, et al., Drug Testing and Analysis (2021)
States these analogues were never approved for human use but are sold on the black market for bodybuilding; found oxidised, lower-quality forms in black-market products; still detectable up to 24 h after a single intramuscular injection in rats.
- 05World Anti-Doping Code International Standard: Prohibited List 2026 (official reproduction, Austrian Federal Law Gazette BGBl. III Nr. 219/2025), World Anti-Doping Agency (2025)
S2.3 names 'Insulin-like growth factor 1 (IGF-1, mecasermin) and its analogues'. Gazette reproduction of the WADA list; the wada-ama.org page is https://www.wada-ama.org/en/prohibited-list.
- 06Misuse of Drugs Act 1971, Schedule 2, Part III (Class C drugs), legislation.gov.uk
Class C hormone list includes somatotropin, somatrem and somatropin; IGF-1 and its variants are not listed.
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Before you trust a vial
Peptides are freeze-dried for a reason. If you have seen IGF-1 DES (1-3) sold pre-mixed in a ready-to-use pen or syringe, here is why that is a red flag for potency, sterility and dosing.
Storage & stability →Stay posted
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