Growth-factor biology
Lab research
Animal and cell studies; mecasermin evidence is not LR3 evidence.1
HormonalProtein
IGF-1 LR3
Long R3 insulin-like growth factor-1 analogue
Research analogue; no FDA-approved IGF-1 LR3 product.
What does it do?
Molecular information
2Amino-acid sequence
An exact sequence has not been verified for this formulation.
LengthNot independently verified
Molecular weight · DaNot independently verified for the exact supplied form
Molecular formulaNot independently verified for the exact supplied form2
Salt, hydration, glycosylation and blend composition may change the supplied material; no unsupported formula or mass is assigned.
Pharmacokinetics
Reported half-lifeNo verified human estimate2
No numerical curve is shown without an exact compound, formulation and human-route match.
No numerical estimate was found in the checked data or Pep-Pedia profile. A curve would require an unsupported assumption.
What to expect
Study outcomes
2025 animal study found no growth benefit
Seven treated growth-restricted fetal sheep and seven controls had similar final body weights after one week. Circulating amino acids decreased with LR3.1
Doses & schedules
Route
Scroll to compare all columns →
| Route | Dose | Frequency | Goal / evidence | Duration | References |
|---|---|---|---|---|---|
| SubQ | 20-30 mcg | Once daily, post-workout | Research Beginner ProtocolReference report | 4-6 weeks maximum | 9 |
Population Population not independently verified; see the reference and linked research. Context Reported in Pep-Pedia’s educational protocol table. Study attribution and applicability to this exact product are not independently established. Source interaction labels and nominal potency/half-life claims are not human dosing evidence. Source tabs Injectable | |||||
| SubQSubcutaneous | 40-60 mcg | Once daily, post-workout or morning | Intermediate Research UseReference report | 4-6 weeks maximum | 9 |
Population Population not independently verified; see the reference and linked research. Context Reported in Pep-Pedia’s educational protocol table. Study attribution and applicability to this exact product are not independently established. Source interaction labels and nominal potency/half-life claims are not human dosing evidence. Source route wording SubQ or IM Source tabs Injectable | |||||
| IMIntramuscular | 40-60 mcg | Once daily, post-workout or morning | Intermediate Research UseReference report | 4-6 weeks maximum | 9 |
Population Population not independently verified; see the reference and linked research. Context Reported in Pep-Pedia’s educational protocol table. Study attribution and applicability to this exact product are not independently established. Source interaction labels and nominal potency/half-life claims are not human dosing evidence. Source route wording SubQ or IM Source tabs Injectable | |||||
| SubQSubcutaneous | 80-100 mcg | Once daily or split AM/PM | Advanced Research ProtocolReference report | 4-6 weeks maximum | 9 |
Population Population not independently verified; see the reference and linked research. Context Reported in Pep-Pedia’s educational protocol table. Study attribution and applicability to this exact product are not independently established. Source interaction labels and nominal potency/half-life claims are not human dosing evidence. Source route wording SubQ or site-specific IM Source tabs Injectable | |||||
| IMIntramuscular | 80-100 mcg | Once daily or split AM/PM | Advanced Research ProtocolReference report | 4-6 weeks maximum | 9 |
Population Population not independently verified; see the reference and linked research. Context Reported in Pep-Pedia’s educational protocol table. Study attribution and applicability to this exact product are not independently established. Source interaction labels and nominal potency/half-life claims are not human dosing evidence. Source route wording SubQ or site-specific IM Source tabs Injectable | |||||
| SubQSubQ only | 10-20 mcg | Once daily | Women's Research ProtocolReference report | 4-6 weeks maximum | 9 |
Population Population not independently verified; see the reference and linked research. Context Reported in Pep-Pedia’s educational protocol table. Study attribution and applicability to this exact product are not independently established. Source interaction labels and nominal potency/half-life claims are not human dosing evidence. Source tabs Injectable | |||||
| IntranasalNasal spray | Unknown | Not determined | No Established ProtocolsReference report | Not specified | 9 |
Population Population not independently verified; see the reference and linked research. Context Reported in Pep-Pedia’s educational protocol table. Study attribution and applicability to this exact product are not independently established. Source interaction labels and nominal potency/half-life claims are not human dosing evidence. Source tabs Nasal | |||||
No protocols match these filters.
Study and label doses retain their study context. Reference reports are unvalidated practices, not personal treatment instructions. Ranges remain ranges; escalation stages are labeled.
Reported use periods and breaks. These do not establish a safe cycle or prove that breaks prevent tolerance.
Injectable
- Use period
- 4-6 weeks maximum
- Break
- Equal or longer off-cycle (4-6+ weeks) for receptor recovery
Reported timing
Within 15-30 minutes post-workout with immediate carbohydrate intake
Nasal
- Use period
- Not established
- Break
- Unknown requirements
Reported timing
Not established
Animal and cell protocols 1
Laboratory exposures cannot establish a human dose.
Scroll to compare all columns →
| Route | Dose | Frequency | Goal / evidence | Duration | References |
|---|---|---|---|---|---|
| OtherFetal circulation | 1.17 ± 0.12 µg/kg/hour | Continuous infusion | Fetal-growth experimentGrowth-restricted fetal sheepAnimals | 1 week | 1 |
Population Growth-restricted fetal sheep Context Animal experiment only; not a human dose conversion. | |||||
No protocols match these filters.
Side effects & safety
Metabolic effects in animals
Circulating amino acids fell in the treated fetal sheep; human consequences are unknown.
1Glucose and growth risks
Hypoglycemia, organ-growth and malignancy concerns; food intake cannot guarantee safety.
Stop symptoms
Low glucose, confusion, profound fatigue, masses, abdominal enlargement, joint/hand symptoms, headache/vision changes.
Nasal route
Human absorption and safety unknown.
Not a complete safety screen. Discuss health decisions with a qualified clinician.
Combinations & interactions
10 entriesCheck cautions and reported pairings. A compatibility claim does not establish that a combination is safe.
HGH
Avoidance reportedExcess growth signaling.9
Reference report · Evidence context: Avoid combinationCJC-1295/ipamorelin
Caution reportedOverlapping GH/IGF-1 axis.9
Reference report · Pep-Pedia label: Use CautionMK-677
Caution reportedOverlapping IGF-1 elevation.9
Reference report · Pep-Pedia label: Monitor CombinationInsulin
Avoidance reportedPotential life-threatening hypoglycemia.9
Reference report · Pep-Pedia label: Avoid CombinationAnabolic steroids
Caution reportedGrowth/metabolic burden.9
Reference report · Pep-Pedia label: Use CautionCerebrolysin
Caution reportedUntested neurotrophic pairing.9
Reference report · Pep-Pedia label: Monitor CombinationBPC-157
Unverified pairingCommunity repair claim, untested.9
Reference report · Pep-Pedia label: SynergisticTB-500
Unverified pairingCommunity repair claim, untested.9
Reference report · Pep-Pedia label: SynergisticMetformin
Unverified pairingGlucose effects need clinical review.9
Reference report · Evidence context: Dose dependentOther medicines and research compounds
Not establishedNo clinical interaction study for the exact proposed combination was verified; absence of evidence does not establish compatibility.2
Research contextNo matching interactions. Try another name or filter.
Reconstitution
No universal bacteriostatic-water volume or validated preparation method is established for this entry.2
Reference preparation details
Reported handling information, not a validated formulation or instruction to prepare an injectable product.
Injectable
Pep-Pedia favors 0.6% acetic acid and warns about stability in bacteriostatic water.
- Solvents mentioned
- 0.6% acetic acid
- Reported parameters
- Its claimed stability contrast is 2–3 days in BAC water versus more than 30 days in acetic acid. · Example: 1 mg in 2 mL gives 500 mcg/mL. · Reported storage: 2–8°C, protected from light.
The source describes gentle mixing and avoiding vigorous shaking.
The reported stability contrast is not an independently verified specification for a particular product.
Nasal
The nasal section explicitly says no validated preparation protocol exists.
The source says animal methods do not establish human concentration or vehicle requirements. Its acid banner is not a validated nasal recipe.
Appearance & documentation
Appearance and a purity certificate cannot establish sterility, identity, or suitability for injection.
Reported variationResearch Chemical StatusReported concernSevere Hypoglycemia RiskReported concernCancer Proliferation ConcernReported appearancePurity Testing EssentialReported variationSpecies-Specific ResponsesReported appearanceProper Cold Storage Required
9Available forms
No verified packaging examples included.
Packaging examples, not a market survey. Approved and research products are not interchangeable.
Storage after mixing
Reconstituted research vials
Pep-Pedia reports these handling limits after mixing. They are not validated stability or sterility limits for your vial.
Pep-Pedia also claims a much longer period with acetic acid. That claim has not been validated as a safe refrigerated shelf life; the full source wording is retained below.
Storage notes
9Lyophilized: -20°C long-term. Reconstituted in acetic acid: 2-8°C up to 1 year. In bac water: 7 days max.
Standard refrigeration if prepared
Storage depends on the formulation, diluent, container, and handling. Follow the specific product label or pharmacist’s instructions.
Evidence limits
View findings →No independently verified human administration study or half-life.1
1 distinct primary sources or abstracts checked. Evidence may concern a parent compound, individual blend ingredient, animal, or cell model; it does not necessarily establish a benefit for this exact product.
Evidence definitions →Research findings
PreclinicalSource context
Source interaction labels and nominal potency/half-life claims are not human dosing evidence.
Compound identity & other names
A modified IGF-1 research protein with reduced binding-protein affinity. Its animal and cell evidence is distinct from native IGF-1 and approved mecasermin.
Research analogue; no FDA-approved IGF-1 LR3 product.
Long R3 insulin-like growth factor-1 analogue2
How it may work
IGF-1-receptor agonism with reduced binding-protein interaction; downstream growth pathways affect multiple tissues.9
2025 animal study found no growth benefit
Seven treated growth-restricted fetal sheep and seven controls had similar final body weights after one week. Circulating amino acids decreased with LR3.
1Research areas and evidence gaps
Growth-factor biology. Animal and cell studies; mecasermin evidence is not LR3 evidence.1
- No independently verified human administration study or half-life.
- Research-market product identity, purity and formulation cannot be established from a publication.
Additional uses listed by Pep-Pedia
Muscle and wasting. Hypertrophy/hyperplasia and anti-catabolic claims are preclinical.9
Tissue repair. Wound, tendon and burn claims include animal or native-IGF-1 extrapolation.9
Metabolism. Nutrient partitioning/glucose effects; chronic exposure may differ.9
Nasal neurological research. Plaque changes without cognitive improvement in cited mouse work.9
Community reports Unvalidated
Body-composition discussions as described by Pep-Pedia.2
No representative survey, independently verified products, or controlled outcomes.
Search coverage and review status
The targeted check identified relevant additional literature or current regulatory information; checked findings are separated from retained bibliography-only references.
- Checked
- 2026-10-12
- Search
- "Long R3 IGF" 2025 2026 site:pubmed.ncbi.nlm.nih.gov; Long R3 IGF fetal sheep
- Catalog
- Pep-Pedia ↗ · 6 listed references retained
- Targeted search, not an exhaustive systematic review.
- Bibliography-only entries are retained for traceability and are not treated as verified findings.
AI-prepared summaries. Independent medical editorial review is pending.
Community poll 10 topics · Pep-Pedia snapshot
Voluntary, unverified reports. These percentages do not measure effectiveness or safety.
Experience
Number of responses to this question: not disclosed.
Duration of use
The source hides 3 additional categories. Their labels and percentages are unavailable.
Number of responses to this question: not disclosed.
Age range
The source hides 1 additional categories. Their labels and percentages are unavailable.
Number of responses to this question: not disclosed.
Gender
Number of responses to this question: not disclosed.
Primary goal
The source hides 2 additional categories. Their labels and percentages are unavailable.
Number of responses to this question: not disclosed.
Effectiveness
The source hides 13 additional categories. Their labels and percentages are unavailable.
Number of responses to this question: not disclosed.
Side effects
The source hides 6 additional categories. Their labels and percentages are unavailable.
Number of responses to this question: not disclosed.
Dosage frequency
The source hides 3 additional categories. Their labels and percentages are unavailable.
Number of responses to this question: not disclosed.
Would recommend
The source hides 4 additional categories. Their labels and percentages are unavailable.
Number of responses to this question: not disclosed.
How discovered
The source hides 2 additional categories. Their labels and percentages are unavailable.
Number of responses to this question: not disclosed.
Source & limitations
The source displays “594 responses” for this profile. This is not a confirmed participant count or a denominator for individual questions.
- Voluntary self-reports from Pep-Pedia visitors; identity, treatment, outcomes and timing are unverified. These data are not efficacy or safety estimates.
- The source displays a profile-wide response label, not a confirmed unique participant count. It stays unchanged across questions. Question-specific denominators and absolute option counts are not exposed.
- Only the top five categories are displayed for some questions. Extra categories are retained as an undisplayed-category count; their labels and percentages are unavailable.
- Displayed percentages are rounded. They may not total 100%, especially where categories are hidden.
- This is a dated snapshot, not a live survey or current recommendation.
References
Original sources and review status. Open a reference to read its summary.
1IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheepAbstract checked
AI-PREPARED SUMMARY
In growth-restricted fetal sheep, a one-week IGF-1 LR3 infusion did not improve growth; circulating amino acids decreased.
2025 animal study found no growth benefit
Seven treated growth-restricted fetal sheep and seven controls had similar final body weights after one week. Circulating amino acids decreased with LR3.
Additional research · Checked 2026-10-12
2Pep-Pedia: IGF-1 LR3 — community referenceCommunity source checked
AI-PREPARED SUMMARY
Accessed October 12, 2026. Secondary descriptions and bibliography; community schedules are unvalidated reports, not recommendations.
3Rat Muscle Hypertrophy Study (Florini et al.)Pep-Pedia report · Primary source not checked
AI-PREPARED SUMMARY
Pep-Pedia reports: The source claims greater lean mass and anabolic signaling in rats than with native IGF-1; the unlinked report needs verification.
Reported population / model
Sprague-Dawley Rats
Reported study details
2.5mg/kg/day · 4 weeks · 15-20% lean mass increase
Pep-Pedia supplies no original study link for this card. Study identity, design, doses and result remain unverified.
Read the Pep-Pedia report ↗Pep-Pedia reference card; original summary of its reported findings · Checked 2026-10-12
4Fetal Sheep Metabolic Study (Children's Hospital Colorado)Pep-Pedia report · Primary source not checked
AI-PREPARED SUMMARY
Pep-Pedia reports: The fetal-sheep report includes 66% insulin suppression and four deaths during chronic infusion from hypoglycemia/hypoxemia, alongside amino-acid depletion.
Reported population / model
Fetal Sheep
Reported study details
6.6μg/kg/h acute, 1.17μg/kg/h chronic · 90 min to 1 week · Study halted early
Pep-Pedia supplies no original study link for this card. Study identity, design, doses and result remain unverified.
Read the Pep-Pedia report ↗Pep-Pedia reference card; original summary of its reported findings · Checked 2026-10-12
5Pig Growth Inhibition StudyPep-Pedia report · Primary source not checked
AI-PREPARED SUMMARY
Pep-Pedia reports: Treated pigs ate and gained less despite the anabolic hypothesis, with lower insulin/IGF measures and GH pulsatility.
Reported population / model
Domestic Pigs
Reported study details
180μg/kg/day · 4 days · Paradoxical growth reduction
Pep-Pedia supplies no original study link for this card. Study identity, design, doses and result remain unverified.
Read the Pep-Pedia report ↗Pep-Pedia reference card; original summary of its reported findings · Checked 2026-10-12
6Guinea Pig Organ StudyPep-Pedia report · Primary source not checked
AI-PREPARED SUMMARY
Pep-Pedia reports: Guinea pigs did not gain more overall weight; relative adrenal, intestinal, kidney and spleen weights increased.
Reported population / model
Guinea Pigs
Reported study details
120μg/day · 7 days · No overall growth, organ-specific effects
Pep-Pedia supplies no original study link for this card. Study identity, design, doses and result remain unverified.
Read the Pep-Pedia report ↗Pep-Pedia reference card; original summary of its reported findings · Checked 2026-10-12
7Cancer Cachexia Rat ModelPep-Pedia report · Primary source not checked
AI-PREPARED SUMMARY
Pep-Pedia reports: The source describes less lean-mass loss in tumor-bearing rats, −28.8 versus −41.4 g; it labels the treatment IGF-1 rather than clearly identifying LR3.
Reported population / model
Tumor-bearing Rats
Reported study details
0.3mg/kg/day · 14 days · 30% lean mass preservation
Pep-Pedia supplies no original study link for this card. Study identity, design, doses and result remain unverified.
Read the Pep-Pedia report ↗Pep-Pedia reference card; original summary of its reported findings · Checked 2026-10-12
8Alzheimer's Mouse Model (5XFAD)Pep-Pedia report · Primary source not checked
AI-PREPARED SUMMARY
Pep-Pedia reports: The mouse model showed altered amyloid plaques and body composition without improved cognition.
Reported population / model
Transgenic Mice
Reported study details
Intranasal LR3 · 7 months · Plaque remodeling without cognitive improvement
Pep-Pedia supplies no original study link for this card. Study identity, design, doses and result remain unverified.
Read the Pep-Pedia report ↗Pep-Pedia reference card; original summary of its reported findings · Checked 2026-10-12
9Pep-Pedia: IGF-1 LR3 — route-specific referenceReference page checked; underlying claims require separate verification.Community source checked
AI-PREPARED SUMMARY
Source page checked across available routes. Protocols, cycles, storage, mechanisms and pairing claims are secondary reports; checking the page does not independently validate those claims. Original concise summaries are used here.
Content coverage audit · Checked 2026-10-12