Side-by-side · Research reference

IGF-1 LR3vsPNC-27

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

BAnimal-StrongHUMAN-REVIEWED18/41 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

PNC-27

p53-HDM-2 Peptide · Membrane-Targeting

32 AAPeptide lengthSarafraz-Yazdi 2022

12-26p53 domain

Pre-clinicalDevelopment stage

In vitro / Pre-clinical only

01Mechanism of Action

Parameter

IGF-1 LR3

PNC-27

Primary target

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

Membrane-bound HDM-2 protein on cancer cell surfaceSarafraz-Yazdi 2022 Krzesaj 2024

Pathway

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

PNC-27 binds to membrane HDM-2 1-109 domain → transmembrane pore formation → rapid necrosis (poptosis)Pincus 2024 Krzesaj 2024

Downstream effect

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

Immediate cell lysis and extrusion of intracellular contents; secondary mitochondrial membrane disruptionPincus 2024 Krzesaj 2024

Feedback intact?

No — exogenous IGF analogue bypasses GH-mediated regulation

N/A — cytotoxic mechanism, not signaling modulation

Origin

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

Chimeric design: p53 transactivating domain (12-26) fused to penetratin CPP sequenceSarafraz-Yazdi 2022

Antibody development

—

02Dosage Protocols

Parameter

IGF-1 LR3

PNC-27

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

Pre-clinical / In vitro

Human use

Not FDA-approved; no published human trials

—

Clinical status

—

Pre-clinical only — no human trials

In vitro and animal model data only.

In vitro concentrations

—

10–100 μM range

Effective concentrations in cell culture studies.

Shorter analogue

—

PNC-28 (28 AA variant)

Retains HDM-2 binding and cytotoxic activity.

03Metabolic / Fat Loss Evidence

Parameter

IGF-1 LR3

PNC-27

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

—

Fat loss mechanism

—

None — cytotoxic anticancer agent

04Side Effects & Safety

Parameter

IGF-1 LR3

PNC-27

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

—

Human safety data

—

None available — no human trials conducted

Normal cell selectivity

—

In vitro: no cytotoxicity to normal cells (MCF-10-2A, peripheral blood mononuclear cells)Sarafraz-Yazdi 2010 Thadi 2020

Normal cells express minimal membrane HDM-2.

Cancer cell specificity

—

Depends on membrane HDM-2 expression levels

Ovarian cancer lines with low membrane HDM-2 showed <30% necrosis.

Cell death mechanism

—

Necrosis (not apoptosis) — rapid membrane lysisPincus 2024

Mitochondrial effects

—

Secondary mitochondrial membrane disruption in cancer cells

Absolute Contraindications

IGF-1 LR3

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

PNC-27

·Human use — no clinical trials or safety data

Relative Contraindications

IGF-1 LR3

·Diabetes or glucose intolerance
·Family history of cancer

PNC-27

—

05Administration Protocol

Parameter

IGF-1 LR3

PNC-27

1. Research use only

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

PNC-27 has not been tested in human subjects. All data derive from in vitro cancer cell line studies and limited animal models. No approved clinical formulation, dosing protocol, or safety profile exists.Pincus 2024

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

In vitro studies used 10–100 μM PNC-27 dissolved in cell culture medium. Peptide was added directly to cancer cell cultures (pancreatic, breast, colon, ovarian, leukemia lines) and incubated for 24–72 hours.

3. Reconstitution (research)

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

Dual-labeled PNC-27 (green on N-terminus, red on C-terminus) demonstrated intact peptide binding to cancer cell membranes with combined yellow fluorescence at 30 minutes, persisting during cell lysis.Sookraj 2010

4. Stability

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

Cytotoxicity correlates directly with membrane HDM-2 expression levels. Blocking HDM-2's p53-binding domain (1-109) with monoclonal antibodies prevents PNC-27-induced necrosis.

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)

PNC-27

— no documented stacks