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Dosage information

IGF-1 dosage

No human dose of IGF-1 LR3 has been established: no human trial of it is registered, and its published doses come from rats given the peptide by implanted pump.12 The approved IGF-1 dosing reviewed here is the Increlex (mecasermin) label for children with severe primary IGF-1 deficiency, where a prescriber sets a weight-based dose.34

This page summarizes published sources for information only. It is not medical advice and does not tell anyone to use a product. Questions about your own health belong with a licensed clinician. For questions about an order or a product, contact us.

No human dose for IGF-1 LR3

No human dose of IGF-1 LR3 has been established. A ClinicalTrials.gov search run on October 24, 2026 returned no registered study of LR3 under five spellings of its name.1 The published LR3 doses reviewed here come from rats that received the peptide through a pump implanted under the skin, which delivers it continuously for days.112 Doses quoted online for LR3 therefore have no human study behind them.1

Two facts make rat numbers a poor guide. First, rats cleared LR3 from the blood much faster than IGF-1, so how long it lasts in a human body is unknown.737 Second, IGF-1 can lower blood sugar, and how strongly LR3 does this in people has never been measured.101 Nothing on this page is a dose for any person.

The approved IGF-1 dose: the Increlex label

Increlex (mecasermin) is labeled for growth failure in children aged 2 and up who have severe primary IGF-1 deficiency, or a growth hormone gene deletion with neutralizing antibodies to growth hormone.3 A prescriber chooses and adjusts each child's dose. The label schedule:

Label item What the Increlex label says
Starting dose 0.04 to 0.08 mg/kg twice daily, by injection under the skin4
Dose increase If well tolerated for at least 1 week, up by 0.04 mg/kg per dose4
Maximum dose 0.12 mg/kg twice daily4
Timing Within 20 minutes before or after a meal or snack; no dose when the meal or snack is skipped6
Route Under the skin only, never into a vein12
After a dose Avoid high-risk activities such as driving or exercise for 2 to 3 hours, especially when treatment starts13
Not for Secondary IGF-1 deficiency (such as growth hormone deficiency or malnutrition), growth promotion after the growth plates have closed, or as a substitute for growth hormone in its approved uses1415

The ceiling matters. The label reports tumors more often in children given higher than recommended doses, or doses that pushed IGF-1 above the normal range for age and sex, and warns that long-term overdose may cause signs of acromegaly.1617 Patients who use insulin or other diabetes medicines may need those doses changed.18

Doses in human studies of recombinant IGF-1

These studies used recombinant human IGF-1 (in one, bound to IGFBP-3), not LR3. They show the dose ranges researchers tested and what happened, not doses anyone should copy.

Study People Dose and route Length Outcome
Long-term pediatric study (2007) 76 children with growth hormone insensitivity 60 to 120 micrograms/kg twice daily, under the skin Up to 12 years Growth rose from 2.8 to 8.0 cm a year in year one, depending on dose1920
Phase 3 ALS trial (2008) 330 adults at 20 centers 0.05 mg/kg twice daily, under the skin 2 years No difference from placebo2122
Randomized trial (2001) 16 healthy postmenopausal women, average age 71 15 micrograms/kg twice daily, self-injected 1 year No change in body composition, bone density or strength2324
Clinical study (1994) 7 obese adults with type 2 diabetes 120 and 160 micrograms/kg twice daily 4 to 52 days Side effects in every patient; all stopped before 8 weeks2526
Randomized trial (2015) 56 recreational athletes 30 or 60 mg a day of the IGF-1/IGFBP-3 complex 28 days No change in fat or lean mass2728

The weight-based doses run from 15 to 160 micrograms/kg per injection, and at the highest, 120 and 160 micrograms/kg, side effects ended treatment early in all 7 adults who received them.232526 Because LR3 binds IGF-binding proteins about 1,000 times more weakly and was 2.5 to 6 times more potent than IGF-1 in rats, none of these figures can be converted into an LR3 amount.293031

Doses in rat studies of LR3

All three studies dosed rats for 7 to 14 days from implanted osmotic pumps, which release the peptide continuously.11535

  • Growing female rats, 14 days: the top IGF-1 dose, 278 micrograms/day, lifted body weight gain, nitrogen balance and feed conversion by 18 to 26%, and 44 micrograms/day of LR3 did about as much. Human growth hormone infused at 213 micrograms/day did not stimulate growth.1132233
  • Male rats given the steroid dexamethasone, 7 days: the top IGF-1 dose, 695 micrograms/day, added 6 g of body weight, and LR3 was about 2.5 times more potent than IGF-1.53034
  • Diabetic rats, 7 days: rats on the top IGF-1 dose, 695 micrograms/day, gained about 48 g, against 11 g on vehicle, and LR3 was 2.5 to 3 times more potent at restoring growth.3536

These are total daily amounts per rat, not amounts per kilogram of body weight.25 They describe animal experiments and are not guidance for people.

Read the full IGF-1 profile for what IGF-1 and LR3 are, and IGF-1 side effects for what was reported at these doses. Peptide dosage basics explains how peptide amounts are written and why research vials come with no human dose.

More on IGF-1

  • IGF-1 side effects

    Side effects of IGF-1 as reported in labels, trials and published studies, with links to the full profile. Reviewed by a qualified reviewer.

IGF-1 in the store

IGF-1 for sale: strengths, stock and shipping are on the product page.

For research use only. Not for human or veterinary use. Read the research use policy.

Frequently asked questions

How much IGF-1 LR3 per day?

No amount has been established for people, because no human trial of LR3 is registered.1 Published LR3 doses come from rats given the peptide by implanted pump for 7 to 14 days, and rat doses are not human doses.25 The approved IGF-1 schedule reviewed here is the Increlex label for children, which a prescriber sets by body weight and times around meals.46

Should you take IGF-1 LR3 daily?

There is no evidence-based schedule for LR3 in people, daily or otherwise, because no human trial of it is registered.1 In rats it left the blood much faster than IGF-1.7 Recombinant IGF-1 (Increlex) is a prescription drug for children with severe primary IGF-1 deficiency, given twice daily within 20 minutes of a meal or snack, and its label warns of severe low blood sugar that has caused seizures.348

What is the half-life of IGF-1 LR3?

No human half-life has been published; a 2026 review lists it as not documented.137 In rats, LR3 was removed from the blood much faster than IGF-1, a difference the authors linked to its poor binding to plasma binding proteins.7 For comparison, the Increlex label gives a mean terminal half-life of 5.8 hours after a single 0.12 mg/kg injection in children with severe primary IGF-1 deficiency.9

Why is Increlex given with a meal?

Because it has insulin-like effects that lower blood sugar: IGF-1 suppresses glucose output from the liver and increases glucose use by other tissues, and severe hypoglycemia leading to seizures has occurred with Increlex treatment.108 The label therefore ties every dose to a meal or snack, given within 20 minutes on either side, and says to skip the dose when the meal is skipped.6

Written by D2C Peptides Editorial Team.

Pending qualified review.

Updated .

Sources

  1. ClinicalTrials.gov API query: all fields for 'IGF-1 LR3', 'Long R3 IGF-I', 'LR3 IGF-1', 'Long R3 IGF-1' or 'LongR3' (run October 24, 2026). ClinicalTrials.gov, U.S. National Library of Medicine, 2026.
  2. Tomas et al. 1993 (J Endocrinol), abstract: LR3IGF-I dose. Journal of Endocrinology (PubMed PMID 8371075), 1993.
  3. INCRELEX (mecasermin) injection, prescribing information revised 07/2025: Highlights, Indications and Usage. U.S. Food and Drug Administration (Drugs@FDA label, BLA 021839), 2025.
  4. Same source as 3: INCRELEX prescribing information revised 07/2025: Highlights, Dosage and Administration.
  5. Tomas et al. 1992 (Biochem J), abstract: IGF-I dose. Biochemical Journal (PubMed PMID 1371669), 1992.
  6. Same source as 3: INCRELEX prescribing information revised 07/2025: 17 Patient Counseling Information (meal timing).
  7. Ballard et al. 1993, abstract: plasma clearance. Growth Regulation (PubMed PMID 7683526), 1993.
  8. Same source as 3: INCRELEX prescribing information revised 07/2025: 5.1 Hypoglycemia.
  9. Same source as 3: INCRELEX prescribing information revised 07/2025: 12.3 Pharmacokinetics (elimination).
  10. Same source as 3: INCRELEX prescribing information revised 07/2025: 12.2 Pharmacodynamics (carbohydrate metabolism).
  11. Same source as 2: Anabolic effects of insulin-like growth factor-I (IGF-I) and an IGF-I variant in normal female rats (Tomas et al.), abstract: design and effects.
  12. Same source as 3: INCRELEX prescribing information revised 07/2025: 2.2 Administration Instructions.
  13. Same source as 3: INCRELEX prescribing information revised 07/2025: 5.1 Hypoglycemia (activity restriction).
  14. Same source as 3: INCRELEX prescribing information revised 07/2025: 1 Indications and Usage, Limitations of use.
  15. Same source as 3: INCRELEX prescribing information revised 07/2025: 4 Contraindications.
  16. Same source as 3: INCRELEX prescribing information revised 07/2025: 5.7 Malignant Neoplasia (dose relationship).
  17. Same source as 3: INCRELEX prescribing information revised 07/2025: 10 Overdosage.
  18. Same source as 3: INCRELEX Patient Information revised 07/2025: before starting (other medicines).
  19. Chernausek et al. 2007, abstract: intervention. Journal of Clinical Endocrinology and Metabolism (PubMed PMID 17192294), 2007.
  20. Same source as 19: Long-term treatment with recombinant insulin-like growth factor (IGF)-I in children with severe IGF-I deficiency due to growth hormone insensitivity (Chernausek et al.), abstract: results.
  21. Subcutaneous IGF-1 is not beneficial in 2-year ALS trial (Sorenson et al.), abstract: methods. Neurology (PubMed PMID 19029516), 2008.
  22. Same source as 21: Sorenson et al. 2008, abstract: results.
  23. One year of insulin-like growth factor I treatment does not affect bone density, body composition, or psychological measures in postmenopausal women (Friedlander et al.), abstract: methods. Journal of Clinical Endocrinology and Metabolism (PubMed PMID 11297574), 2001.
  24. Same source as 23: Friedlander et al. 2001, abstract: conclusion.
  25. Adverse effects of recombinant human insulin-like growth factor I in obese insulin-resistant type II diabetic patients (Jabri et al.), abstract: methods. Diabetes (PubMed PMID 8314009), 1994.
  26. Same source as 25: Jabri et al. 1994, abstract: discontinuation.
  27. The Effects of Recombinant Human IGF-I/IGFBP-3 Administration on Body Composition and Physical Fitness in Recreational Athletes (Guha et al.), abstract: intervention. Journal of Clinical Endocrinology and Metabolism (PubMed PMID 26046967), 2015.
  28. Same source as 27: Guha et al. 2015, abstract: results.
  29. Same source as 7: Effects of interactions between IGFBPs and IGFs on the plasma clearance and in vivo biological activities of IGFs and IGF analogs (Ballard et al.), abstract: binding affinity.
  30. Same source as 5: Insulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated rats (Tomas et al.), abstract: relative potency.
  31. Same source as 7: growth potency in rats.
  32. Same source as 2: IGF-I dose response.
  33. Same source as 2: growth hormone comparison.
  34. Same source as 5: catabolic model.
  35. Tomas et al. 1993 (Biochem J, diabetic rats), abstract: IGF-I dose. Biochemical Journal (PubMed PMID 7683875), 1993.
  36. Same source as 35: Insulin-like growth factor-I and more potent variants restore growth of diabetic rats without inducing all characteristic insulin effects (Tomas et al.), abstract: relative potency.
  37. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration (Dominikowski et al., Front Endocrinol 17:1822475). Frontiers in Endocrinology (PMC full text, PMC13322892), 2026.