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IGF-1 DES

A truncated IGF-1 that is roughly ten times more potent locally but clears in minutes, which is why it is injected directly into the muscle you just trained.

Also known as DES(1-3)IGF-1, des-IGF, des(1-3) IGF-I

Animal data only — Rodent or other animal studies. Dose translation to humans is genuinely uncertain.

The tenfold potency figure comes from cell culture and rodent work and is real, but no human trial has ever tested DES(1-3)IGF-1 for muscle growth. The specific claim that site injection grows the injected muscle preferentially has never been demonstrated in people.

How it works

DES(1-3)IGF-1 is human IGF-1 missing the N-terminal Gly-Pro-Glu tripeptide. Losing those three residues cuts IGFBP-3 affinity by a very large margin while leaving IGF-1 receptor binding essentially intact, so in tissue where binding proteins would normally sequester IGF-1 it behaves as a far more potent agonist - roughly tenfold in many cell systems. The signalling downstream is identical to native IGF-1: PI3K/Akt/mTOR for protein synthesis and satellite cell activation, MAPK for proliferation. The removed GPE tripeptide is itself a neuroactive fragment, which is an interesting aside but not why anyone injects this. Because nothing protects it in circulation, it is cleared within roughly half an hour, which is exactly the property site-injection protocols are trying to exploit.

Targets: IGF-1 receptor (IGF1R), PI3K/Akt/mTOR pathway, IGF binding proteins (largely evaded)

Dosing

ProtocolDoseFrequencyRoute
Post-workout site injectionWithin 15-30 minutes of finishing the session, split across the muscle group just trained.50 mcg – 150 mcgonce daily on training daysintramuscular
Conservative starting protocolPost-workout with a carbohydrate-containing meal.50 mcg – 75 mcgonce daily on training dayssubcutaneous
  • · Purely anecdotal. The short half-life is the entire rationale, so dosing at any other time makes little sense on the theory people are using.
  • · Lower risk of a blood-sugar crash than jumping straight to 150 mcg.

Titration

Start at 50 mcg and stay there for the first several sessions to see how your blood sugar behaves.

Cycling

Typically run in 4-6 week blocks alongside a hypertrophy phase, then stopped. Nobody has established whether continuous use downregulates the receptor in humans.

Work out your exact syringe units →

Pharmacology

Half-life
Roughly 20-30 minutes in circulation - far shorter than LR3 because nothing shields it from clearance.
Onset
Local pump and fullness within minutes; any real tissue effect takes weeks of repeated use.
Routes
intramuscular, subcutaneous
Molecule
Truncated recombinant IGF-1 analogue (polypeptide)
Sequence length
67 amino acids
Molecular weight
7371.5 Da

Handling

Diluent
0.6% acetic acid for stability; bacteriostatic water for short-term use
Typical mix
1 or 2 mL
Vial sizes
1 mg
Lyophilised
Freezer long term; fridge for shorter periods.
Reconstituted
Refrigerated, used within about 2 weeks; less if reconstituted with plain bacteriostatic water.
Light sensitive
Yes — keep it out of the light

Mixing

A 1 mg vial in 1 mL gives 1000 mcg/mL, so 100 mcg is 10 units on a U-100 syringe. Swirl gently, never shake.

Side effects

  • very commonLocal swelling and a strong pump sensation— Mostly fluid; it subsides within hours.
  • commonHypoglycaemia— Faster in onset than with LR3 but shorter-lived. Eat with the dose.
  • commonInjection-site soreness— Compounded by injecting into a muscle you just trained hard.
  • rarePromotion of existing neoplasia— Mechanistic concern shared by everything in the IGF class.

Do not use if

  • Any active or suspected malignancy.
  • Active proliferative diabetic retinopathy.
  • Concurrent insulin use without close glucose monitoring.
  • Pregnancy and breastfeeding.

Combining it

  • cautioninsulin-analogues — Additive and fast-onset hypoglycaemia.
  • redundantigf-1-lr3 — Same receptor, same pathway. Running both adds risk without a demonstrated additive benefit.
  • synergymgf — Frequently stacked as a post-workout local injection pair; the rationale is theoretical.

What to monitor

  • · Fasting glucose and HbA1c.
  • · Symptom awareness for hypoglycaemia in the hour after dosing.
  • · Current age-appropriate cancer screening before starting.

Legal status

Not approved for human use. Sold as a research chemical and prohibited in sport at all times by WADA.

References

  • Preclinical studies showing DES(1-3)IGF-1 has markedly reduced IGFBP affinity and increased potency versus native IGF-1 (preclinical)
  • Reviews of IGF-1 structure-activity relationships and binding-protein biology (review)

Mechanism in depth

DES(1-3)IGF-1 is the cleanest experiment in this whole class: take native IGF-1, remove three residues from the N-terminus, and watch what happens when a growth factor loses almost all binding-protein affinity while keeping full receptor affinity. What happens is that it becomes the most potent variant tested in every IGFBP-containing system and the fastest cleared in vivo. Tomas ranked acute hypoglycaemic potency in pigs and marmosets as IGF-I < long-IGF-I < R3IGF-I approximately LR3IGF-I < des(1-3)IGF-I, so DES sits at the top. The Gly-Pro-Glu tripeptide is a contact region for IGFBP-3 and IGFBP-1; delete it and affinity drops far enough that Ballard could describe association with plasma binding proteins as essentially absent. Downstream everything is standard IGF1R biology - IRS-1/PI3K/Akt splitting into mTORC1 translation initiation, FoxO nuclear export with suppression of MAFbx and MuRF1, GSK-3beta inactivation, plus the Shc/ERK proliferative arm. The clinically interesting consequence of the short half-life is that DES cannot sustain mTORC1 activation across the multi-hour window that translational work suggests is needed for a meaningful synthetic response, which is why the post-workout local-pulse rationale is more folklore than pharmacology. The cleaved GPE tripeptide, incidentally, is glypromate, a neuroprotective agent studied in its own right - a nice illustration of how much of this molecule's identity lived in the three residues that were removed.

What usually goes wrong

The mistake specific to DES is treating the short half-life as a safety feature. It is not; it is a potency multiplier compressed into a shorter window. Tomas found DES the most hypoglycaemically potent variant tested, so 100 mcg of DES is a more abrupt event than 100 mcg of LR3 even though it is over faster. People dose it higher than LR3 precisely because it lasts less time, which is exactly backwards. The second mistake is believing that intramuscular injection into a trained muscle produces localised growth in that muscle. This has never been shown in humans for any IGF-1 analogue, and injecting into small muscles at high dose has produced a good share of the injection-site nodule and fibrosis reports. The third is product identity: DES is chemically closer to native IGF-1 than LR3 is, and there is a long history of grey-market vials sold as DES that turn out to be ordinary rhIGF-1 or nothing at all.

Titration ladder

  1. 50 mcgFirst 3 training days — Post-workout, immediately before a full carbohydrate-containing meal. Glucose checked at 30 minutes.
  2. 75 mcgRest of weeks 1-2 — Only if the 50 mcg sessions were symptom-free.
  3. 100 mcgWeek 3 onward — Practical ceiling for most people. The commonly quoted 150 mcg upper bound has no rationale behind it beyond escalation for its own sake.

Bloodwork worth running

MarkerWhenWhy it matters
Capillary glucose or CGM, timed tightly around the injection15, 30, 45 and 60 minutes after the first injection at any new dose.DES produces the sharpest glucose nadir of the IGF-1 analogues. Because the whole event is compressed into under an hour, a fasting glucose the next morning will show you nothing at all.Act if: Below 70 mg/dL (3.9 mmol/L) at any timepoint means the dose is too high for how you are eating around it.
Serum IGF-1Baseline only, unless stacking with GH or a secretagogue.Less about DES itself, which most assays will not see because the epitope is altered and the molecule is gone within the hour, and more about establishing where your endogenous axis sits before you start adding to it.Act if: Above the age-adjusted reference range at baseline is a reason not to start.
Cancer screening appropriate to age and sexBefore first use, then at standard screening intervals.Same mitogenic logic as the rest of the IGF-1 class, and DES is the most receptor-potent member of it.Act if: Any abnormal finding stops the plan.

Pharmacokinetics

Crosses blood-brain barrier
partial
Metabolism
Receptor-mediated internalisation, then hepatic and renal proteolysis.
Elimination
Kidney took up more label than any other organ in the rat tracer study. No intact excretion.

Receptor targets

  • IGF-1 receptor (IGF1R) — Essentially native IGF-1 affinity retained despite the truncation

    Full agonism, with higher effective potency in any system containing binding proteins because free fraction is far higher.

  • IGF binding proteins, particularly IGFBP-1 and IGFBP-3 — Dramatically reduced; association with plasma binding proteins was 'essentially absent' in Ballard's tracer work

    The engineered defect. Highest free fraction and fastest clearance in the family.

  • Insulin receptor — Weak, comparable to native IGF-1

    Contributes to the acute glucose drop, which is more abrupt than with LR3 because peak free concentration is higher.

What to expect, and when

Glucose effects start within 10-20 minutes, peak fast and are largely resolved within 60-90 minutes. Local swelling in the injected muscle within minutes to an hour, which is fluid. Nothing visible in a mirror before four to six weeks, and honestly nothing attributable to the compound rather than the training at any point, because no human study has ever separated the two.

Stacking and comparisons

The common practice is DES on training days for a local post-workout pulse and LR3 on rest days for systemic coverage. There is no evidence this beats either alone, and it doubles the number of hypoglycaemic events per week. If you insist, do not let the two overlap in the same four-hour window. With insulin the objection is stronger than for LR3, because DES produces a higher peak free concentration - the nadirs stack rather than average. With GH the redundancy argument applies as before, though GH-driven insulin resistance genuinely does blunt DES's glucose drop. The one combination with any mechanistic logic is DES immediately post-workout in someone whose session has already emptied muscle glycogen and raised GLUT4 translocation, taken with the post-workout carbohydrate, because the glucose disposal then has somewhere useful to go.

Against LR3, DES is the higher-potency, shorter-exposure option: sharper glucose drop, briefer anabolic signal, no realistic prospect of sustained mTORC1 activation. If your working theory is that muscle needs a prolonged translational signal, LR3 fits it better and DES does not fit it at all. If the theory is a discrete post-workout pulse with satellite cell activation, DES fits better, but that theory has no human support either. Against mecasermin, the same point as for LR3: mecasermin is the only member of this family with measured pharmacokinetics, a known adverse-event rate and a regulator who read the file. Against MGF, which is also sold as a post-workout local agent, DES at least has a defined receptor and decades of animal pharmacology behind it; MGF has neither.

Rough cost

$90–$300/month. 1 mg vials commonly 60-120 USD grey market, and 100 mcg on four training days a week is roughly 1.6 mg a month. DES is usually priced above LR3 because it is less commonly stocked.

Genuinely uncertain

  • No human pharmacokinetic data for des(1-3)IGF-1 exist. The 20-30 minute half-life in the Core record is extrapolated from rat and pig clearance data, not measured in people.
  • Whether the truncation alters immunogenicity relative to native IGF-1 has not been assessed in humans.
  • The local-injection hypothesis is untested. There is no human study showing site-specific hypertrophy from intramuscular IGF-1 analogue administration.
  • Relative IGF1R affinity of des(1-3)IGF-I versus native IGF-1 is reported as similar or slightly higher across sources, but exact Kd values differ between assay systems and no single authoritative number could be resolved.
  • Grey-market product identity is a genuine unknown; there is no published mass-spectrometry survey of DES products the way there now is for some other performance peptides.

Papers