IGF-1 DES

Dosing from the Literature

Published for muscle: animal studies of the compound itself — rats, pigs and marmoset monkeys. Not published: any human dose of IGF-1 DES.

No FDA-approved dose exists for IGF-1 DES, and no human pharmacokinetic, dose-finding or safety study has been published. The rows below are the doses published animal studies used. The figures that circulate online have no published source behind them, so this page does not list them.

What It Is

IGF-1 DES — full name "Des(1-3) IGF-1" or "DES(1-3) insulin-like growth factor-I" — is a naturally occurring N-terminally truncated variant of insulin-like growth factor-1. It lacks the first three amino acids of the mature IGF-1 sequence (glycine-proline-glutamic acid; the "GPE" tripeptide), resulting in a 67-amino-acid single-chain protein versus 70 amino acids for mature native IGF-1. The molecular weight is approximately 7,400 Da compared to 7,649 Da for native IGF-1.

IGF-1 DES was first isolated and characterized from human brain tissue by Sara, Carlsson-Skwirut, and colleagues in the mid-1980s (Sara et al., Proc Natl Acad Sci USA 1986; PMID 3460078), who identified it as a brain-enriched IGF-1 variant with anomalously high biological activity in cell-culture assays. The same truncated form was subsequently identified in bovine colostrum, fetal tissue, and under certain in vitro processing conditions. It is understood to arise from post-translational proteolytic cleavage of mature IGF-1 by specific proteases in those tissues — it is not a separately-encoded gene product but a naturally occurring degradation or processing variant.

The structural basis of IGF-1 DES's enhanced biological activity was established through a series of papers in the late 1980s and 1990s, most notably Francis, Ross, and colleagues (Francis et al., Biochem J 1988; PMID 3390164). The removal of the N-terminal GPE tripeptide (a chain of 3 amino acids) does not meaningfully change binding to the IGF-1 receptor itself — receptor affinity is largely preserved — but it dramatically reduces binding affinity for all six members of the insulin-like growth factor binding protein family (IGFBPs 1–6). In circulation, more than 95% of native IGF-1 is sequestered in a ternary complex with IGFBP-3 and acid-labile subunit (ALS), which extends its half-life but limits its immediate receptor availability. IGF-1 DES, being largely free from IGFBP sequestration, remains predominantly bioavailable at the receptor — which is the mechanistic origin of its 5–10-fold higher in vitro potency at equivalent mass doses.

IGF-1 DES has never been advanced into a human clinical development program. It is distinct from mecasermin (Increlex), the FDA-approved recombinant human IGF-1 marketed by Ipsen for severe primary IGF-1 deficiency in children, which is sequence-identical to native 70-amino-acid IGF-1 with no N-terminal truncation. Conflating IGF-1 DES with mecasermin — a frequent error in community literature — obscures the very different regulatory and evidence foundations. The synthetic recombinant IGF-1 DES sold through research-chemical channels for community body-composition use has no formal human clinical characterization.

Mechanism of Action

At the receptor, IGF-1 DES behaves much like native IGF-1; what differs is how much of it is free to reach the receptor, because the IGF binding proteins barely hold it (Ross et al., 1989; Carlsson-Skwirut et al., 1989). The potency measured in cells follows from that, not from a different response at the receptor (Ross et al., 1989).

• IGF-1 receptor (IGF-1R) binding and activation — The truncated form binds the IGF-1 receptor at least as well as native IGF-1: in membranes from human fetal and adult brain and placenta it was 1.4–5 times more potent at displacing labelled IGF-1 (Carlsson-Skwirut et al., 1989). The receptor is homologous to the insulin receptor and sits on most types of cells and tissues (Increlex label).
• IGFBP evasion — In blood, native IGF-1 is bound to six IGF binding proteins, more than 80% of it in a complex with IGFBP-3 and an acid-labile subunit (Increlex label). The variant lacks the N-terminal Gly-Pro-Glu tripeptide (Francis et al., 1988), and a binding protein that abolished native IGF-1's activity in cultured cells left the truncated form's activity untouched; across the three IGFs, biological potency ran inversely to binding-protein binding (Ross et al., 1989). A binding protein from human amniotic fluid had 100-fold lower affinity for the truncated form (Carlsson-Skwirut et al., 1989).
• Potency in cells — In rat L6 myoblasts the truncated form stimulated protein synthesis and inhibited protein breakdown more potently than native IGF-1, a roughly 10-fold difference (Francis et al., 1988). In fetal rat brain cells it was 4 times more potent at stimulating DNA synthesis (Carlsson-Skwirut et al., 1989).
• Cleared faster, not slower — Injected into rats, labelled des(1-3)IGF-1 stayed mostly free in plasma and was removed about four times faster than native IGF-1 (clearances 4.59 against 1.20 ml/min per kg), while reaching the adrenals, brain, skin and gut to a greater extent; the authors proposed that the plasma binding proteins hold IGF-1 back from its tissue sites of action (Ballard et al., 1991). No half-life in people has been published.
• Insulin-like effects on blood sugar — In pigs and marmoset monkeys, the variants that bind the binding proteins poorly were 2–3 times more potent than native IGF-1 at lowering blood sugar and held it down over a much longer period, des(1-3)IGF-1 most of all; the authors proposed action on liver insulin receptors or suppression of glucagon (Tomas et al., 1997). Native IGF-1 suppresses the liver's glucose output, raises glucose uptake by other tissues and damps insulin secretion (Increlex label).
• Muscle — In rats on a low-protein diet, des(1-3)IGF-1 at 1.2 mg/kg a day raised the rate of muscle protein synthesis 21% and improved nitrogen balance (Tomas et al., 1991). In mice, a muscle-restricted transgene of a locally acting native IGF-1 isoform produced lasting fibre hypertrophy, more mass and strength, muscle that escaped age-related atrophy, and the regenerative response of younger animals (Musarò et al., 2001) — that transgene is native IGF-1, not the truncated form.
• Brain — It was first isolated from human fetal brain, where it stimulated DNA synthesis in fetal brain cells (Sara et al., 1986); the recombinant truncated form was 4 times more potent than IGF-1 in fetal rat brain cells (Carlsson-Skwirut et al., 1989). The tripeptide cut from it, Gly-Pro-Glu, is itself active on rat brain tissue (Sara et al., 1989).
• Not growth hormone — Growth hormone binds its own receptor in the liver and other tissues and makes them produce IGF-1 (Increlex label); IGF-1 and its truncated form act further down that chain, at the IGF-1 receptor.

What the Research Shows

The IGF-1 DES evidence base is entirely preclinical — cell-culture potency work, rodent, pig and monkey studies, and receptor pharmacology. No human controlled clinical trials of IGF-1 DES have been published.

• Original brain isolation (Sara et al., PNAS 1986; PMID 3460078) — The foundational paper identifying IGF-1 DES as a naturally occurring brain-enriched truncated IGF-1 variant with anomalously high biological activity in bioassay.
• IGFBP-evasion mechanism (Francis et al., Biochem J 1988; PMID 3390164) — Established the reduced IGFBP binding as the molecular basis for enhanced in vitro bioactivity. Functional potency in cell-culture assays 5–10× native IGF-1 at matched mass doses.
• Plasma clearance in rats (Ballard et al., J Endocrinol 1991; PMID 2005410) — Labelled des(1-3)IGF-1 barely associated with plasma binding proteins and was cleared about four times faster than native IGF-1, yet reached the adrenals, brain, skin and gut to a greater extent. The authors proposed that binding proteins hold IGF-1 back from its tissue sites, and that analogues cleared quickly from blood may still be more potent in the body.
• Colostrum IGF-1 DES (Francis et al., Biochem J 1988; PMID 3390164) — The truncated form was purified from bovine colostrum alongside IGF-1 and IGF-2, and its full amino-acid sequence determined.
• Anabolic effect in rats (Tomas et al., J Endocrinol 1991; PMID 1999680) — In young rats moved to a 4% protein diet, des(1-3)IGF-1 infused at 1.2 mg/kg a day for 7 days improved nitrogen balance and raised the fractional rate of muscle protein synthesis 21%, without measurably raising plasma IGF-1.
• Hypoglycaemia in pigs and monkeys (Tomas et al., J Endocrinol 1997; PMID 9415072) — Five IGF-1 forms were given to pigs at 20 and 50 mcg/kg, and IGF-1 and des(1-3)IGF-1 to marmosets at 42–270 mcg/kg. Des(1-3)IGF-1 lowered blood sugar most and held it down longest.
• Muscle-specific IGF-1 transgenic phenotype (Musarò et al., Nat Genet 2001; PMID 11175789) — Mice carrying a muscle-restricted transgene of a locally acting native IGF-1 isoform showed persistent fibre hypertrophy, higher muscle mass and strength, muscle that escaped age-related atrophy, and the regenerative response of younger animals. The transgene is native IGF-1, not IGF-1 DES.
• Cancer risk class context — A review of the IGF system reports that people with serum IGF in the upper quartile of the normal range, with IGFBP-3 in the lower quartiles, carry a raised relative risk of breast, prostate, colon and lung cancer, and that the IGF-1 receptor is often overexpressed in cancers (LeRoith & Roberts, 2003). IGF-1 DES acts at the same receptor.
• No human clinical trial — ClinicalTrials.gov lists no study of IGF-1 DES under any of its names (checked October 4, 2026), and PubMed holds no human trial of it. Every claim about people is extrapolation from preclinical data.

Human Data

Human data on IGF-1 DES is essentially absent. The closest related human-evidence reference is mecasermin (recombinant native IGF-1) — a different molecule — used in severe primary IGF-1 deficiency.

• No published human IGF-1 DES clinical trial — No controlled human pharmacokinetic, pharmacodynamic, or efficacy study has been reported. All community use is extrapolation from preclinical data.
• Mecasermin (native rhIGF-1) — closest human reference — The approved native IGF-1, Increlex, is given under the skin twice daily to children 2 and older with growth failure from severe primary IGF-1 deficiency, or from a growth hormone gene deletion with antibodies to GH (Increlex label). In its trials, 71 children treated for a mean of 3.9 years reported hypoglycemia (42% of them), lipohypertrophy, bruising, middle-ear infection and fluid, snoring, tonsillar hypertrophy, headache, dizziness, convulsions, vomiting, joint and limb pain and thymus enlargement among the reactions occurring in 5% or more; the label also carries intracranial hypertension, allergic reactions including anaphylaxis, slipped capital femoral epiphysis, scoliosis progression and reports of cancers (Increlex label). Mecasermin is a different molecule, so none of this transfers to IGF-1 DES directly; it is the closest human safety frame there is.
• Observational IGF-1 and cancer epidemiology — A review of the IGF system reports that people with serum IGF in the upper quartile of the normal range, with IGFBP-3 in the lower quartiles, carry a raised relative risk of breast, prostate, colon and lung cancer (LeRoith & Roberts, 2003). Relevant context for any IGF-1-axis-stimulating peptide.
• Community self-report — uncontrolled — Bodybuilding community self-report of IGF-1 DES site-specific injections for local muscle growth is plentiful but is not clinical evidence. Variable product quality, unreliable dosing, and absence of systematic outcome measurement preclude drawing clinical inferences.
• No human study — ClinicalTrials.gov lists no study of IGF-1 DES under any of its names (checked October 4, 2026), and PubMed holds no human trial of it. Its pharmacokinetics, dose and long-term safety in people are undocumented.

Reconstitution & Storage

Guide pages describe IGF-1 DES as a lyophilized (freeze-dried) powder from research reagent suppliers, often in 1 mg vials.

• Reconstitution — Guide pages describe adding the liquid slowly down the vial wall and swirling the vial gently rather than vortexing it, since the protein can aggregate at the air–liquid interface. The label for native IGF-1 says not to use a solution that is cloudy or holds particles (Increlex label).
• Solvent — For laboratory use, guide pages list sterile water, 0.1 M acetic acid, 10 mM hydrochloric acid or phosphate-buffered saline; for the vials sold online they list bacteriostatic water or 0.6% acetic acid. The approved native IGF-1 solution is itself buffered with glacial acetic acid and sodium acetate, at a pH of about 5.4 (Increlex label).
• Storage — powder — Guide pages list −20 to −80°C for the freeze-dried powder, kept dry.
• Storage — mixed — Guide pages disagree: one gives up to a week at 4°C for a working stock, with single-use portions frozen for longer; another gives one to two weeks refrigerated. The label for native IGF-1 allows 30 days at 2–8°C after a vial is first opened, and says to avoid freezing it and to protect it from light (Increlex label).

→ Calculator — vial-to-syringe math

Side Effects & Risks

• Hypoglycemia (low blood sugar) — The main safety signal in the animal work. In pigs and marmoset monkeys, the IGF-1 variants that bind the binding proteins poorly were 2–3 times more potent than native IGF-1 at lowering blood sugar and held it down over a much longer period; of the five forms tested, des(1-3)IGF-1 was the most potent (Tomas et al., 1997). Native IGF-1 suppresses the liver's glucose output, raises glucose uptake by other tissues and damps insulin secretion, which is where its hypoglycemic potential comes from, and severe hypoglycemia leading to seizures has occurred on the approved native IGF-1 (Increlex label).
• What users describe — Guide summaries of forum reports list muscle fullness during training, blood-sugar drops, brief effects and injection-site pain. None of it has been measured in a study.
• Systemic IGF-1 and organ growth — In rats given des(1-3)IGF-1 for 7 days, measured plasma IGF-1 did not rise, though binding proteins did, and kidney weight rose 16% (Tomas et al., 1991). In IGF-1-deficient rats, native rhIGF-1 produced whole-body and organ growth (Increlex label).
• Theoretical cancer risk — The IGF system drives cell division and has powerful anti-apoptotic effects, and people with serum IGF in the upper quartile of the normal range, with IGFBP-3 in the lower quartiles, carry a raised relative risk of breast, prostate, colon and lung cancer; the IGF-1 receptor is often overexpressed in cancers (LeRoith & Roberts, 2003). Trials of antibodies against that receptor disappointed in unselected patients (Pollak, 2012). Cancers have been reported in children given the approved native IGF-1, which is contraindicated for a child with a cancer or a history of one (Increlex label).
• No long-term human safety data — The compound has never been through human clinical trials. Chronic-use consequences are unknown.
• WADA-banned (S2) — IGF-1 and its analogs are specifically prohibited under WADA S2 (peptide hormones, growth factors, related substances and mimetics). Detection methods for IGF-1 and its variants are established in WADA-accredited laboratories. Not viable for tested athletes.
• Drug interactions — The patient information for the approved native IGF-1 says the dose of insulin or other anti-diabetes medicines may need to change (Increlex label). Growth hormone acts on its receptor in the liver and other tissues and makes them produce IGF-1 (Increlex label), so giving growth hormone raises the body's own IGF-1 alongside anything injected.
• Sourcing / identity concerns — Guide pages report that product quality varies between sellers. Nothing published documents the purity, dose consistency or sterility of what is sold as IGF-1 DES.

Bloodwork & Monitoring

No trial, label or guideline sets monitoring for IGF-1 DES, and no human study has measured anything on it. For the approved native IGF-1 (mecasermin), a different molecule, the label calls for blood-sugar checks before meals until a well-tolerated dose is found, an eye (funduscopic) examination at the start and periodically, periodic checks for enlarged tonsils and adenoids, assessment of any limp or hip or knee pain, watching a pre-existing scoliosis for progression, and stopping the drug if a cancer appears (Increlex label).

Commonly Stacked With

Stacking this? Read the receipt →

→ Calculator — vial-to-syringe math

Legal Status

Related Compounds

People researching IGF-1 DES often also look at these:

Next Steps

References

1. Sara VR, Carlsson-Skwirut C, Andersson C, Hall E, Sjögren B, Holmgren A, Jörnvall H. Characterization of somatomedins from human fetal brain: identification of a variant form of insulin-like growth factor I. Proc Natl Acad Sci USA. 1986;83(13):4904-4907. PMID: 3460078. (Original brain isolation of truncated IGF-1.)
2. Francis GL, Upton FM, Ballard FJ, McNeil KA, Wallace JC. 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;251(1):95-103. PMID: 3390164. (Seminal characterization of IGFBP-evasion mechanism.)
3. Ballard FJ, Knowles SE, Walton PE, Edson K, Owens PC, Mohler MA, Ferraiolo BL. Plasma clearance and tissue distribution of labelled insulin-like growth factor-I (IGF-I), des(1-3)IGF-I and IGF-II in rats. J Endocrinol. 1991;131(1):87-93. PMID: 2005410.
4. Musarò A, McCullagh K, Paul A, Houghton L, Dobrowolny G, Molinaro M, Barton ER, Sweeney HL, Rosenthal N. Localized Igf-1 transgene expression sustains hypertrophy and regeneration in senescent skeletal muscle. Nat Genet. 2001;27(2):195-200. PMID: 11175789. (Foundational muscle-specific IGF-1 phenotype.)
5. Ross M, Francis GL, Szabo L, Wallace JC, Ballard FJ. Insulin-like growth factor (IGF)-binding proteins inhibit the biological activities of IGF-1 and IGF-2 but not des-(1-3)-IGF-1. Biochem J. 1989;258(1):267-272. PMID: 2539101.
6. Carlsson-Skwirut C, Lake M, Hartmanis M, Hall K, Sara VR. A comparison of the biological activity of the recombinant intact and truncated insulin-like growth factor 1 (IGF-1). Biochim Biophys Acta. 1989;1011(2-3):192-197. PMID: 2469478.
7. Sara VR, Carlsson-Skwirut C, Bergman T, Jörnvall H, Roberts PJ, Crawford M, Håkansson LN, Civalero I, Nordberg A. Identification of Gly-Pro-Glu (GPE), the aminoterminal tripeptide of insulin-like growth factor 1 which is truncated in brain, as a novel neuroactive peptide. Biochem Biophys Res Commun. 1989;165(2):766-771. PMID: 2574573. (Companion GPE tripeptide neuroactivity characterization.)
8. Pollak M. The insulin and insulin-like growth factor receptor family in neoplasia: an update. Nat Rev Cancer. 2012;12(3):159-169. PMID: 22337149. (IGF-1 pathway and cancer epidemiology — central class-level safety framing.)
9. LeRoith D, Roberts CT Jr. The insulin-like growth factor system and cancer. Cancer Lett. 2003;195(2):127-137. PMID: 12767520.
10. Tomas FM, Knowles SE, Chandler CS, Francis GL, Owens PC, Ballard FJ. Anabolic effects of insulin-like growth factor-I (IGF-I) and an IGF-I variant in normal female rats. J Endocrinol. 1993;137(3):413-421. PMID: 8371075. (In vivo anabolic effects of IGF-1 DES vs native IGF-1.)
11. Philipps AF, Kling PJ, Grille JG, Dvoráková S. Intestinal transport of insulin-like growth factor-I (IGF-I) in the suckling rat. J Pediatr Gastroenterol Nutr. 2002;35(4):539-544. PMID: 12394381. (Colostrum IGF-1 DES context.)
12. Cohick WS, Clemmons DR. The insulin-like growth factors. Annu Rev Physiol. 1993;55:131-153. PMID: 8466170. (Class review.)
13. Williams ED, et al. Comparison of des(1-3)IGF-1 and IGF-1 in promoting wound healing. Growth Factors. 1991 context. (Wound-healing preclinical reference.)
14. U.S. Food and Drug Administration. Increlex (mecasermin) Prescribing Information. Ipsen Biopharmaceuticals. First approved 2005. (Context: FDA-approved recombinant native IGF-1 — different molecule from IGF-1 DES.)
15. WADA. 2026 World Anti-Doping Code Prohibited List. Section S2 — Peptide hormones, growth factors, related substances and mimetics. World Anti-Doping Agency. (IGF-1 and analogs class prohibition.)
16. FDA. Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the FD&C Act (503A categories list), versions updated April 15, April 22 and May 14, 2026. fda.gov/media/94155/download. Read October 3, 2026. (Notice that 12 peptides would leave Category 2 because their nominations were withdrawn; their removal; GHK-Cu, except injectable, back in Category 1.)
17. Stone W. The wellness world is eager for RFK Jr.’s promised move on peptides. NPR, March 31, 2026. npr.org/2026/03/31/nx-s1-5768206/peptides-rfk-fda-compounding-pharmacies. Read October 3, 2026. (The HHS secretary’s late-February podcast remarks, “about 14” peptides; reported, not a rule.)
18. Tomas FM, Walton PE, Dunshea FR, Ballard FJ. 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):377-386. PMID: 9415072. (Hypoglycaemic potency of des(1-3)IGF-I in pigs and marmosets.)
19. Tomas FM, Knowles SE, Owens PC, Read LC, Chandler CS, Gargosky SE, Ballard FJ. Effects of full-length and truncated insulin-like growth factor-I on nitrogen balance and muscle protein metabolism in nitrogen-restricted rats. J Endocrinol. 1991;128(1):97-105. PMID: 1999680. (In vivo anabolic effects of des(1-3)IGF-I in rats.)
20. Eton Pharmaceuticals. Increlex (mecasermin) injection prescribing information. DailyMed set ID d5b2b0e1-c523-468d-9a0b-4ae4e4a8dbce, version effective May 18, 2026. dailymed.nlm.nih.gov. Read October 4, 2026. (Native rhIGF-1; a different molecule from IGF-1 DES.)

Related Research

• IGF-1 LR3IGF-1 Receptor Agonist (Long R3 Analog)
• MGFIGF-1 Splice Variant / Satellite Cell Activator
• PEG-MGFPEGylated IGF-1 Splice Variant
• GHRP-2Growth Hormone Secretagogue (Ghrelin Receptor Agonist)
• FDA TrackerPCAC voted on 7 of the 12 peptides on July 23–24, 2026; FDA plans a PCAC review of the other 5 before the end of February 2027.