Research peptides

IGF-1 DES: What It Is, Research, Dosage and Legal Status

Q: What is IGF-1 DES?

A shortened form of human insulin-like growth factor 1 (IGF-1) missing its first 3 amino acids (glycine, proline and glutamate), leaving 67 of 70. It occurs naturally: it has been isolated from cow colostrum and found in human brain tissue. Researchers use it as a lab tool because the missing amino acids sharply reduce its binding to IGF-binding proteins, leaving more free to act on the IGF-1 receptor.

IGF-1 DES (des(1-3)IGF-1): a truncated, fast-acting IGF-1 fragment sold for muscle use - what the animal research shows, common dosing and legal status.

Written bySebastian Hunter, Founder and EditorI'm a 42-year-old senior advisor and distance runner who came to peptides as a sceptic. I'm not a doctor: I read the research, run my own experiment and keep honest notes. Read full bio

Published September 27, 2026Updated October 1, 2026

The short version

IGF-1 DES, also written des(1-3)IGF-1, is a natural, shortened form of insulin-like growth factor 1 that binds much less to the proteins that hold IGF-1 in reserve. It is not FDA-approved and is a different molecule from IGF-1 LR3 and from mecasermin, the one approved IGF-1 drug. No controlled human trial has tested it for muscle, and in animals it lowered blood sugar more, and for longer, than native IGF-1 or IGF-1 LR3.

Not FDA-approved for any indication; not the same molecule as IGF-1 LR3 or the approved drug mecasermin.
A natural IGF-1 fragment first studied as a lab reagent; no controlled human trial for muscle gain exists.
In an animal study it lowered blood sugar the most of several IGF-1 variants: a low-blood-sugar signal measured for this molecule itself.
Dosing guides cite a very short half-life, yet in rats it was still in the blood 24 hours after one injection, longer than IGF-1 LR3.

IGF-1 DES at a glance

What it is: Truncated 67-amino-acid analogue of insulin-like growth factor 1, missing its first three residues
Main use: Originally isolated and studied as a naturally occurring IGF-1 fragment in laboratory pharmacology, used to probe IGF-1 receptor signalling with reduced interference from binding proteins. Sold to consumers as a research chemical for localised, site-specific muscle growth, a use with no controlled human trial behind it.
Also called: Des(1-3)IGF-1, IGF-1 Des(1-3), Truncated IGF-1
Size: 67 amino acids Details
Evidence: Animal / lab only
US status: Research use only
Half-life: Not established in humans
How it is taken: Intramuscular injection
Common protocol: 20-120 mcg, on training days only, about 4-5 times a week, not on rest days, for 4-6 weeks (common practice, not trial-established) Dosage chart

Dosing: the common protocol.

IGF-1 DES, also written des(1-3)IGF-1, is a natural, shortened form of human IGF-1 that lacks its first 3 amino acids. That small change sharply reduces how much it is held back by its carrier proteins, which made it a useful lab tool for studying IGF-1 signalling.

Sold to consumers, it is a research chemical marketed for injecting into a trained muscle on workout days. No controlled human trial has tested that use.

US legal status - Research use only

Sold for laboratory research use only. Not approved by the FDA for human use, and cannot be lawfully marketed as a supplement or a medicine. Products sold this way are not made to pharmaceutical quality standards, and their contents are not verified by anyone.

What is IGF-1 DES?

The name is short for des(1-3)-insulin-like growth factor 1. “Des” means the first 3 amino acids (glycine-proline-glutamate) have been removed from the front (the N-terminus) of IGF-1’s 70-amino-acid chain, leaving 67 (Ballard 1996 - Ballard FJ, Wallace JC, Francis GL et al. Des(1-3)IGF-I: a truncated form of insulin-like growth factor-I. Int J Biochem Cell Biol. 1996;28(10):1085-7., in the references below).

Unlike IGF-1 LR3, which was engineered in a lab, IGF-1 DES is reported to occur naturally. It has been isolated from cow colostrum and found in human brain and other tissue, and probably comes from a normal step in how the body processes IGF-1 (Ballard 1996 - Ballard FJ, Wallace JC, Francis GL et al. Des(1-3)IGF-I: a truncated form of insulin-like growth factor-I. Int J Biochem Cell Biol. 1996;28(10):1085-7., in the references below).

How it works

Most IGF-1 in the blood is bound to IGF-binding proteins (IGFBPs). These carriers hold it in reserve and control how much is free to act on the IGF-1 receptor. Removing the first 3 amino acids sharply reduces binding to these proteins.

A published review says des(1-3)IGF-1 is generally about 10 times more potent than native IGF-1 at making cultured cells grow and divide (Ballard 1996 - Ballard FJ, Wallace JC, Francis GL et al. Des(1-3)IGF-I: a truncated form of insulin-like growth factor-I. Int J Biochem Cell Biol. 1996;28(10):1085-7., in the references below). That comes from the weaker carrier binding, not from tighter binding to the receptor itself. In living animals, only part of that extra potency survives. This is the basis for its use as a research reagent, and for how it is now marketed.

IGF-1 DES structure

Length: 67 amino acids
Sequence: TLCGAELVDALQFVCGDRGFYFNKPTGYGSSSRRAPQTGIVDECCFRSCDLRRLEMYCAPLKPAKSA
Modifications: Human IGF-1 (70 residues) minus its N-terminal Gly-Pro-Glu; three disulfide bonds (Cys3-Cys45, Cys15-Cys58, Cys44-Cys49 in this 67-residue numbering).

No PubChem compound record. The sequence is the natural human IGF-1 chain (UniProt P05019, residues 49-118) with the first three residues removed, as described in the paper that isolated it.

Sequence checked against Francis et al., Biochem J 1988.

IGF-1 DES vs IGF-1 LR3: two different truncations

IGF-1 DES and IGF-1 LR3 both cut down interference from the binding proteins, but in different ways. Vendor marketing confuses them constantly.

	IGF-1 DES	IGF-1 LR3
Origin	Naturally occurring cleavage product of IGF-1	Engineered laboratory construct
Modification	First 3 amino acids removed (67 residues total)	Glu3→Arg substitution plus a 13-amino-acid N-terminal extension (83 residues total)
Duration of action claimed by dosing guides	Very short - described as cleared quickly	Described as lasting substantially longer than native IGF-1
Unchanged molecule in rat blood after one intramuscular injection Mongongu 2021 - Mongongu C, Coudoré F, Domergue V et al. 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 Test Anal. 2021;13(7):1256-1269., in the references below	Still detectable at 24 hours	Disappeared rapidly after about 4 hours
Sold for	Localised, training-day intramuscular use	Sustained, less frequent systemic use

Not mecasermin: two different molecules

The only IGF-1 product the FDA has approved is mecasermin (brand name Increlex), which is unmodified recombinant human IGF-1. Its DailyMed label says it is indicated “for the treatment of growth failure in pediatric patients 2 years of age and older with severe primary IGF-1 deficiency or with growth hormone (GH) gene deletion who have developed neutralizing antibodies to GH.” It is a 10 mg/mL injection under the skin, prescribed and monitored by a doctor for a rare childhood hormone condition.

IGF-1 DES has a shortened sequence chosen to behave differently from full-length IGF-1. It has no FDA approval, no DailyMed listing and no approved use. Evidence, dosing and safety data for mecasermin don’t transfer to it.

IGF-1 DES research: what has been studied

Animal / lab only

Studied in cells or animals. No controlled trials in humans. I could not find a controlled human trial of IGF-1 DES, for muscle or anything else, in the source registry this site cites from. What is published is cell and binding-protein pharmacology, plus animal studies: continuous infusion in rats with reduced kidney mass or after gut surgery, and single intravenous injections in pigs and marmoset monkeys measuring blood sugar. None uses the injection into muscle that consumers buy it for.

The animal work is real pharmacology, but it doesn’t answer what most buyers want to know. Two rat studies found muscle-sparing, growth-promoting effects:

Reduced kidney mass. In rats with part of the kidneys surgically removed, 7 days of continuous infusion at 0.9 mg per kg of body weight per day increased weight gain and nitrogen balance and reduced muscle protein breakdown (Martin 1991 - Martin AA, Tomas FM, Owens PC et al. IGF-I and its variant, des-(1-3)IGF-I, enhance growth in rats with reduced renal mass. Am J Physiol. 1991;261(4 Pt 2):F626-33., in the references below).
Gut resection. In rats with 80% of the small intestine removed, continuous infusion at 0.96 mg/kg/day led to weight regain and a more positive nitrogen balance than untreated controls over the following days (Lemmey 1991 - Lemmey AB, Martin AA, Read LC et al. IGF-I and the truncated analogue des-(1-3)IGF-I enhance growth in rats after gut resection. Am J Physiol. 1991;260(2 Pt 1):E213-9., in the references below).

Both are genuine anabolic signals. But they come from surgically compromised rats on continuous infusion at just under 1 mg/kg a day, not the microgram doses injected into muscle on training days that consumers use.

I found no IGF-1 DES study, human or animal, with a clinical-trial registry ID I could verify. Where I can’t check a study against a real registry entry, I don’t name it or cite a paper for it.

IGF-1 DES dosage

The common IGF-1 DES dose is 20-120 mcg, on training days only, about 4-5 times a week, not on rest days. From a 1 mg vial mixed with 2 mL of bacteriostatic water, 70 mcg is 14 units (0.14 mL) on a U-100 insulin syringe.

See the full IGF-1 DES dosage chart →

There is no established human dose, because there is no controlled human trial and no approved product. Dosing guides most often describe:

20-120 mcg injected into muscle
on training days only, roughly 4-5 times a week
within 10-15 minutes of finishing training, followed straight away by fast-acting carbohydrate.

That is common practice, not something a trial established. Full detail and sourcing: IGF-1 DES dosage.

IGF-1 DES side effects

There is no long-term human safety data for IGF-1 DES. There is one animal study that measured its effect on blood sugar directly.

Low blood sugar (hypoglycaemia), measured for this molecule in animals. A study compared IGF-1 and several variants with weak binding-protein attachment in pigs and marmoset monkeys (Tomas 1997 - Tomas FM, Walton PE, Dunshea FR 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;155(2):377-86., in the references below). des(1-3)IGF-1 lowered blood glucose the most of all the variants, including IGF-1 LR3. At doses with equal glucose-lowering effect, its total effect was about twice that of native IGF-1 and lasted several hours. This was in pigs and in anaesthetised and conscious marmosets, not people. Unlike the hypoglycaemia risk usually given for IGF-1 LR3, it isn’t borrowed from another drug’s label, and it was the biggest signal in the study.
Abnormal tissue growth: an open question. IGF-1 signalling drives cell growth and division. No study has tested whether unsupervised IGF-1 DES use changes that risk in people.
Product quality. IGF-1 DES is sold as a research chemical labelled not for human use. No regulator checks that a vial matches its label, and I found no public testing programme that checks identity, purity or concentration.

For redness, itching or swelling at the injection site, see injection-site reactions.

Is IGF-1 DES legal, and is it banned in sport?

A published anti-doping study calls IGF-1 DES, IGF-1 LR3 and R3-IGF-1 prohibited substances in sport, “never approved for use in humans” yet “available as black market products for bodybuilding” (Mongongu 2021 - Mongongu C, Coudoré F, Domergue V et al. 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 Test Anal. 2021;13(7):1256-1269., in the references below). The same study validated a detection method. It found unchanged des(1-3)IGF-1 in rat blood up to 24 hours after one injection into muscle, and the authors suggest the result may apply to humans (Mongongu 2021 - Mongongu C, Coudoré F, Domergue V et al. 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 Test Anal. 2021;13(7):1256-1269., in the references below).

IGF-1 and its analogues fall under the World Anti-Doping Agency’s S2 category (peptide hormones, growth factors and related substances), banned at all times, in and out of competition. If you are a tested athlete, check the current WADA Prohibited List at wada-ama.org yourself.

I checked only US federal law, not US states or other countries.

IGF-1 DES is one of several IGF-1 variants sold for muscle and recovery with no controlled human trial behind that use. IGF-1 LR3 is the one it is most often confused with. Dosing guides say it is commonly stacked with injury-recovery peptides, injected into the same muscle.

Regulatory changes for this compound and others, as they happen: US peptide regulation tracker.

How IGF-1 DES compares

Growth hormone and growth factors. Doses for unapproved compounds are common practice, not trial-established. All growth hormone and muscle peptides →

Compound	Main use	Evidence	Usual dose	US status
HGH 191AA	Marketed to consumers for body recomposition, recovery and anti-aging in adults who do not have a diagnosed growth hormone deficiency. The identical molecule, somatropin, is FDA-approved by prescription for defined deficiency and wasting conditions - see the "Where approved somatropin fits" section on the main guide for that distinction.	Limited human data	333-1333 mcg, Once daily (split into a morning and evening dose above roughly 3 IU/day), subcutaneous	Research use only
IGF-1 LR3	Originally engineered as a laboratory reagent - an IGF-1 variant with reduced binding to IGF-binding proteins, used to study IGF-1 signalling in cell culture. Sold to consumers as a research chemical for muscle growth, a use with no controlled human trial behind it.	Animal / lab only	20-50 mcg, once daily	Research use only
IGF-1 DES	Originally isolated and studied as a naturally occurring IGF-1 fragment in laboratory pharmacology, used to probe IGF-1 receptor signalling with reduced interference from binding proteins. Sold to consumers as a research chemical for localised, site-specific muscle growth, a use with no controlled human trial behind it.	Animal / lab only	20-120 mcg, on training days only, about 4-5 times a week, not on rest days	Research use only
MGF	Marketed to consumers as a peptide injected directly into a trained muscle immediately after exercise, for local muscle repair and growth. No completed human trial has tested it for this or any outcome.	Animal / lab only	100-400 mcg, Immediately post-workout, 2-3 times a week (training days only)	Research use only
PEG-MGF	Marketed to consumers for muscle repair and growth after resistance training. Never approved for human use; FDA states it has identified no human exposure data on it by any route.	Animal / lab only	200-400 mcg, 2-3 times a week, post-workout	Research use only
Follistatin	The body's own brake on activin and myostatin signalling, studied academically as a gene-therapy payload for muscle-wasting disease. Sold separately, as an injected research-chemical protein, for grey-market muscle-building use that its own human trials have never tested.	Animal / lab only	100-500 mcg, 2 to 4 times a week	Research use only

Where to buy IGF-1 DES for research

Each vendor is checked against my vendor checklist.

I don't list a vendor for IGF-1 DES yet. Before buying from anyone, work through the vendor checklist.

See all vendors and how they compare →

Common questions

Is IGF-1 DES the same as IGF-1 LR3?

No. Both bind poorly to IGF-binding proteins, but they are different molecules. IGF-1 DES is shorter (67 amino acids), occurs naturally, and is said to clear quickly. IGF-1 LR3 is longer (83 amino acids), made in a lab, and is said to last much longer. The one study that measured both in rat blood found the reverse: IGF-1 DES was still there at 24 hours, LR3 gone after about 4. In another animal study, IGF-1 DES lowered blood sugar more than LR3. See the full comparison below.

Is IGF-1 DES the same as mecasermin (Increlex)?

No. Mecasermin is unmodified recombinant human IGF-1, the only IGF-1 product the FDA has approved, for growth failure in children with severe primary IGF-1 deficiency. IGF-1 DES is a shortened variant with a different sequence and binding profile. Evidence about one does not transfer to the other.

Does IGF-1 DES work for muscle growth?

I found no controlled human trial of IGF-1 DES for muscle gain, body composition or performance. What is published is receptor and binding-protein pharmacology, rat studies using continuous infusion after kidney or gut surgery, and blood-sugar studies in pigs and marmoset monkeys. None tests what happens when a person repeatedly injects it into a trained muscle, which is how it is sold.

What is the usual IGF-1 DES dose?

No controlled human trial has tested a dose. Dosing guides most often describe 20-120 mcg injected into muscle on training days only (about 4-5 times a week), within 10-15 minutes of finishing, with fast-acting carbohydrate to offset the blood-sugar drop. That is common practice, not something a trial established. Full detail: [IGF-1 DES dosage](/igf-1-des-dosage/).

What are the side effects of IGF-1 DES?

There is no long-term human safety data. The clearest signal is low blood sugar: in pigs and marmoset monkeys, it lowered blood glucose more than any other IGF-1 variant tested, including IGF-1 LR3, and for longer than native IGF-1. Whether it raises the risk of abnormal tissue growth is an open question nobody has studied in people. It is sold as an unregulated research chemical, and no regulator checks that a vial matches its label.

Can IGF-1 DES cause hypoglycaemia?

In animals, yes, and the study measured this molecule directly. In pigs and marmoset monkeys, it lowered blood glucose more, and for longer, than native IGF-1 and every other variant tested, including IGF-1 LR3. No human trial has measured it, which is why dosing guides pair every injection with fast-acting carbohydrate.

Is IGF-1 DES legal in the United States?

It is not FDA-approved for any use, and I found no IGF-1 DES product on DailyMed when I searched on 27 September 2026. It is not a dietary supplement or a cosmetic. It is sold as a research chemical labelled not for human use, which is a label, not a legal category.

Is IGF-1 DES banned in sport?

Yes. A published anti-doping study calls IGF-1 DES, IGF-1 LR3 and R3-IGF-1 prohibited in sport, never approved for human use but sold on the black market for bodybuilding. IGF-1 and its analogues fall under WADA's S2 category (peptide hormones, growth factors and related substances), banned at all times. Tested athletes should check the current WADA list themselves.

How long does IGF-1 DES stay in the body?

I couldn't verify a human half-life against a primary source, so I don't give one. Dosing guides call it very short, tens of minutes, which is why they time it around workouts. The one published blood measurement doesn't support that: after one injection into muscle in rats, unchanged IGF-1 DES was still detectable at 24 hours, while IGF-1 LR3 was gone after about 4.

Is IGF-1 DES better than IGF-1 LR3 for muscle growth?

No study has compared them for muscle growth in people, so there is no evidence either way. They are marketed differently: IGF-1 DES for injecting into a specific muscle on training days, IGF-1 LR3 for less frequent whole-body dosing. In animals, IGF-1 DES lowered blood sugar more than LR3, which is a safety signal, not a muscle comparison.

Is high IGF-1 good or bad?

Raising IGF-1 with a drug has documented risks; what a high blood-test result means is for a doctor to interpret. The label of mecasermin, the only FDA-approved IGF-1 drug, warns of low blood sugar and of reports of malignant tumours in treated children, seen more often when IGF-1 was pushed above normal (cause unknown). It rules the drug out for children with cancer or a history of it. In animals, IGF-1 DES lowered blood sugar more than native IGF-1.

What happens if your IGF-1 is low?

In children, severe primary IGF-1 deficiency causes growth failure. The mecasermin (Increlex) label defines it as very short stature plus a very low IGF-1 level with normal or raised growth hormone, and that FDA-approved drug treats it. What a low result means for an adult is a question for a doctor. IGF-1 DES is not approved to treat low IGF-1 or anything else.

How can I increase my IGF-1 levels?

In trials, drugs that make the pituitary release more growth hormone raised blood IGF-1: CJC-1295 in healthy adults, and MK-677 in healthy older adults, where fasting blood sugar also rose. Neither is an approved medicine. IGF-1 DES is an unapproved IGF-1 variant, not a treatment for a low level. Take a low IGF-1 result to a doctor rather than treating it yourself.

References (9 sources)

Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.