Side-by-side · Research reference

IGF-1 LR3vsVIP

Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.

AAnimal-StrongHUMAN-REVIEWED10/58 cited

BPhase 3HUMAN-REVIEWED9/42 cited

IGF-1 LR3

IGF-1 Analogue · Research

3–10×Potency vs IGF-I

Low IGFBPBinding affinity

ResearchStatus

Research only · SQ typical in animal models

VIP

Neuropeptide · VPAC1/VPAC2 Agonist · Emergency Use Authorization (COVID-19 ARDS)

IntravenousPrimary routeBrown 2023

ARDSLead indicationUdupa 2025

Phase 3Development stage

IV infusion · Inhaled (investigational)Brown 2023 Boesing 2022

01Mechanism of Action

Parameter

IGF-1 LR3

VIP

Primary target

IGF-1 receptor (IGF-1R)McTavish 2009

VPAC1 and VPAC2 G-protein-coupled receptorsUdupa 2025

Pathway

IGF-1R → IRS-1 → PI3K/Akt → Cell proliferation, protein synthesis, anti-apoptosisMuhlbradt 2009

VIP → VPAC1/VPAC2 activation → cAMP elevation → Pulmonary vasodilation + epithelial protection

Downstream effect

Enhanced cell proliferation, muscle anabolism, inhibition of apoptosis, increased telomerase activity

Anti-inflammatory cytokine modulation, alveolar-capillary membrane stabilization, pulmonary smooth muscle relaxation, reduced neutrophil infiltration

Feedback intact?

No — exogenous IGF analogue bypasses GH-mediated regulation

Yes — exogenous VIP acts as physiological agonist

Origin

Synthetic 83-AA analogue: 13-AA N-terminal extension + Arg substitution at position 3

Endogenous 28-amino-acid neuropeptide; synthetic analogue (aviptadil) identical to natural VIP

Antibody development

—

02Dosage Protocols

Parameter

IGF-1 LR3

VIP

Research dose (animal models)

Variable by protocol and species

In vivo murine atherosclerosis studies used sustained delivery.

—

In vitro typical concentration

10–1000 ng/mLThomas 2007

Dose-dependent effects on follicle growth and estradiol production.

—

Half-maximal stimulation

0.6 nM LR3 vs 1.5 nM native IGF-1Price 2004

2.5-fold greater potency in lung fibroblast proliferation.

—

Evidence basis

Animal / in vitro only

Phase 3 RCT (TESICO)Brown 2023

816-patient randomized controlled trial in COVID-19 ARDS.

Human use

Not FDA-approved; no published human trials

—

Intravenous (ARDS protocol)

—

60–90 mcg/kg/day via continuous infusion

TESICO trial protocol for COVID-19 ARDS.

Infusion duration

—

12-hour continuous IV infusion dailyBrown 2023

Inhaled (investigational)

—

Variable dosing under clinical trial protocolsBoesing 2022

Delivered via nebulizer for direct pulmonary deposition.

Treatment duration

—

3–14 days (acute ARDS)

Reconstitution

—

Lyophilized powder reconstituted with sterile diluent per protocol

Half-life

—

~2 minutes (plasma)

Rapid clearance necessitates continuous infusion.

03Metabolic / Fat Loss Evidence

Parameter

IGF-1 LR3

VIP

Mechanism

IGF-1R activation → lipolytic signaling; secondary to anabolic effects

—

Direct lipolytic evidence

Minimal — primarily anabolic/anti-apoptotic in literature

—

Atherosclerotic plaque effects

Reduced stenosis and core size in ApoE-KO micevon 2011

Plaque stabilization via vSMC phenotype modulation, not direct fat loss.

—

Human data

None published

—

04Side Effects & Safety

Parameter

IGF-1 LR3

VIP

Hypoglycemia risk

Theoretical — IGF-1 analogues can lower blood glucose

—

Excessive cell proliferation

Mitogenic signaling; theoretical tumor promotion risk

—

Telomerase activation

2–10-fold increase in prostate cancer cells (PC-3, DU-145, LAPC-4)Wetterau 2003

Critically involved in cancer cell immortalization.

—

Oocyte degeneration

Increased oocyte degeneration at high doses (≥1000 ng/mL) in bovine folliclesThomas 2007

—

Unregulated anabolism

Bypasses physiological GH/IGF-1 feedback; no pulsatility control

—

Unknown human safety profile

No published human trials; safety data absent

—

Hypotension

—

Transient vasodilation-related blood pressure drop

Tachycardia

—

Reflex tachycardia secondary to vasodilation

Infusion site reactions

—

Erythema, phlebitis (IV administration)

GI symptoms

—

Nausea, diarrhea (VIP is endogenous GI peptide)

Overall tolerability

—

Well-tolerated in Phase 3 trials; adverse event profile comparable to placebo

Absolute Contraindications

IGF-1 LR3

·Active malignancy or history of cancer
·Not approved for human use

VIP

·Known hypersensitivity to aviptadil or formulation components

Relative Contraindications

IGF-1 LR3

·Diabetes or glucose intolerance
·Family history of cancer

VIP

·Severe hypotension or shock states (monitor blood pressure)
·Pregnancy — insufficient safety data

05Administration Protocol

Parameter

IGF-1 LR3

VIP

1. Research use only

IGF-1 LR3 is not FDA-approved for human use. All administration data derives from animal or in vitro studies.

Reconstitute lyophilized aviptadil powder with sterile diluent per manufacturer protocol. Inspect solution for particulates — should be clear and colorless.

2. Typical research route

Subcutaneous or intraperitoneal injection in animal models. In vitro: added directly to culture medium at concentrations of 10–1000 ng/mL.Thomas 2007

Administer as continuous 12-hour intravenous infusion via central or peripheral line. Use infusion pump for precise dosing (60–90 mcg/kg/day divided over infusion duration).

3. Reconstitution (research)

Lyophilised powder reconstituted in sterile water or buffered saline per manufacturer protocol. Store at 2–8 °C after reconstitution.

Monitor blood pressure, heart rate, and oxygenation continuously during first infusion. Assess for hypotension and adjust infusion rate if needed.

4. Stability

Enhanced stability vs native IGF-1 due to reduced IGFBP binding; exact half-life in vivo not fully characterized in humans.

Deliver via jet or mesh nebulizer per clinical trial protocol. Patient seated upright, normal tidal breathing for 10–15 minutes.

5. Storage

—

Store lyophilized powder at 2–8 °C, light-protected. Reconstituted solution: use immediately or within 24 hours if refrigerated.

06Stack Synergy

IGF-1 LR3

+ GHRP-6

Multi-pathway

View GHRP-6 →

GHRP-6 stimulates endogenous GH release, which drives hepatic IGF-1 synthesis. IGF-1 LR3 provides exogenous, IGFBP-resistant IGF signaling. Combining upstream GH stimulation with downstream IGF receptor activation creates a dual-pathway anabolic effect. However, this bypasses natural feedback and carries compounded mitogenic risk.

GHRP-6: 100–200 mcg SQ · 2–3× daily
IGF-1 LR3: Research doses variable · post-workout typical in animal models
Note: Research context only — no human protocols exist
Primary benefit: Theoretical maximal anabolic signaling (GH + IGF axes)

+ Ipamorelin

Multi-pathway

View Ipamorelin →

Ipamorelin (selective GHRP) stimulates pulsatile GH release without cortisol/prolactin elevation. IGF-1 LR3 directly activates IGF-1R independent of GH. This stack targets both upstream (GH secretion) and downstream (IGF receptor) nodes but eliminates physiological feedback, raising safety concerns around unchecked proliferation.

Ipamorelin: 200–300 mcg SQ · evening
IGF-1 LR3: Research doses only · timing variable
Caution: No human data; animal/in vitro only
Primary benefit: Dual-axis anabolic signaling (theoretical)

VIP

— no documented stacks