Side-by-side · Research reference

CortagenvsPEG-MGF

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

AAnimal-MechanisticHUMAN-REVIEWED11/35 cited

BAnimal-MechanisticHUMAN-REVIEWED2/69 cited

Cortagen

Bioregulatory Tetrapeptide · Khavinson-School

TetrapeptideStructure

↓ LPO productsAntioxidant effectKozina 2007

AnimalEvidence level

Injectable · Animal models

PEG-MGF

IGF-1Ec Splice Variant · PEGylated

~2 hrHalf-life (PEG)

~7 minNative MGF t½

IGF-1EcSplice variant

SQ · Research Protocol

01Mechanism of Action

Parameter

Cortagen

PEG-MGF

Primary target

Cerebral cortex tissue — molecular targets under investigation

IGF-1 receptor on muscle satellite cells and myocytes

Pathway

Antioxidant pathway modulation — suppression of LPO cascade, reduction of protein oxidative modificationKozina 2007

IGF-1R → PI3K/Akt → mTOR activation → Satellite cell proliferation & myoblast fusion

Downstream effect

Decreased lipid peroxidation products, reduced oxidative protein damage, altered gene expression in cardiac tissueKozina 2007 Anisimov 2004

Satellite cell activation, muscle fiber repair, localized hypertrophy signaling

Feedback intact?

—

Partially bypassed — does not require hepatic IGF-1 synthesis

Origin

Synthetic tetrapeptide derived from amino acid analysis of natural brain cortex peptide preparation CortexinAnisimov 2004

IGF-1Ec splice variant (exon 4–6) conjugated to polyethylene glycol for extended circulation

Antibody development

—

Unknown — no long-term human immunogenicity data

02Dosage Protocols

Parameter

Cortagen

PEG-MGF

Animal model dose (rat)

Injection protocol (dose not specified in abstracts)

Multiple injections over study period.

—

Avian model dose (chicken)

40-day injection courseKuznik 2008

Compared to epithalon in hypophysectomized and aged birds.

—

Human peripheral nerve study

Therapeutic course (protocol details not provided)

Posttraumatic recovery context — reference cited but not detailed.

—

Evidence basis

Animal mechanistic studies

Animal / mechanistic

Route

Injectable (inferred from animal protocols)

—

Research dose range

—

100–200 mcg

Extrapolated from animal models; no validated human protocols.

Frequency

—

Post-training or daily

Timing to match endogenous MGF pulse post-exercise.

Half-life

—

~2 hours (PEGylated)

Native MGF: ~7 min; PEGylation extends circulation.

Reconstitution

—

Sterile bacteriostatic water

Lyophilized form; store reconstituted at 2–8 °C.

PEG molecular weight

—

Typically 5–30 kDa

Higher MW = longer t½, greater steric hindrance.

Timing

—

Within 30–60 min post-training

Aligns with endogenous MGF window.

03Metabolic / Fat Loss Evidence

Parameter

Cortagen

PEG-MGF

Primary target

—

Muscle tissue (satellite cells, myocytes) — not adipose-specific

Indirect metabolic effect

—

IGF-1 signaling may modulate insulin sensitivity and lipid metabolismRen 2015

Mechanism distinct from direct lipolytic peptides.

Body composition

—

Lean mass preservation / hypertrophy focus

Fat loss evidence

—

No direct human or animal RCT data for PEG-MGF-driven fat reduction

04Side Effects & Safety

Parameter

Cortagen

PEG-MGF

Antioxidant suppression

Suppression of antioxidant activity noted alongside LPO reductionKozina 2007

Mechanism unclear — possible homeostatic adaptation.

—

Immune/hemostasis effects

No effect on immunity or hemostasis parameters in avian hypophysectomy model (unlike epithalon)Kuznik 2008

Epithalon reversed deficits; cortagen did not.

—

Human safety data

No adverse events reported in peripheral nerve recovery context

Limited detail in available abstracts.

Absent — no published human trials for PEG-MGF

Injection site reaction

—

Erythema, induration (common with SQ peptides)

Hypoglycemia risk

—

IGF-1 axis activation can lower blood glucose

IGF-1R overstimulation

—

Theoretical risk of aberrant cell proliferation with chronic supraphysiological exposure

Fluid retention

—

Possible with IGF-1 pathway activation (dose-dependent)

PEG accumulation

—

Chronic high-dose PEGylated proteins may accumulate in tissues; clearance slower in renal impairment

Antibody formation

—

PEGylated proteins can elicit anti-PEG antibodies (neutralizing potential unknown)

Cancer risk

—

IGF-1 axis stimulation contraindicated in active malignancy

Absolute Contraindications

Cortagen

—

PEG-MGF

·Active malignancy or history of cancer (IGF-1R proliferative signaling)
·Known hypersensitivity to PEGylated compounds
·Pregnancy / lactation (no reproductive toxicity data)

Relative Contraindications

Cortagen

—

PEG-MGF

·Diabetes (monitor glucose closely)
·Renal impairment (PEG clearance reduced)
·Retinopathy (IGF-1 axis effects on vascular proliferation)

05Administration Protocol

Parameter

Cortagen

PEG-MGF

1. Preparation

Reconstitute lyophilised peptide with bacteriostatic water per supplier protocol. Exact volumes depend on concentration supplied.

Add 1–2 mL bacteriostatic water to lyophilized vial. Swirl gently — do not shake. Solution should be clear to slightly opalescent.

2. Injection site

Subcutaneous injection typical for bioregulatory peptides — abdomen or thigh. Rotate sites.

Subcutaneous — abdomen or thigh. Rotate sites to avoid lipodystrophy. Avoid areas with scar tissue or active inflammation.

3. Timing

Animal protocols used repeated dosing over weeks. Human timing not established — evening administration common in Khavinson tradition.

Post-training preferred (within 30–60 min) to align with endogenous MGF expression window. Alternatively, daily morning dose on non-training days.

4. Storage

Lyophilised: refrigerate or freeze per supplier. Reconstituted: refrigerate 2–8 °C, use within guideline window.

Lyophilized: room temperature, light-protected, desiccated. Reconstituted: refrigerate 2–8 °C, use within 14–21 days.

5. Needle

—

29–31G insulin syringe, 8–12 mm length. Pinch skin fold, insert at 45° angle for subcutaneous delivery.

06Stack Synergy

Cortagen

— no documented stacks

PEG-MGF

+ BPC-157

Moderate

View BPC-157 →

BPC-157 promotes angiogenesis and tendon/ligament repair via VEGF and growth factor modulation, while PEG-MGF targets satellite cell activation and myocyte proliferation. Complementary pathways for comprehensive tissue repair post-injury or intensive training. BPC-157's systemic stability and oral bioavailability contrast with PEG-MGF's localized IGF-1R signaling.

PEG-MGF: 100–200 mcg SQ post-training
BPC-157: 250–500 mcg SQ or oral, twice daily
Duration: 4–6 weeks (injury-dependent)
Primary benefit: Accelerated muscle and connective tissue repair, enhanced recovery

+ TB-500

Strong

View TB-500 →

TB-500 (Thymosin Beta-4 fragment) upregulates actin polymerization, cell migration, and anti-inflammatory pathways, while PEG-MGF drives satellite cell proliferation via IGF-1R/mTOR. Synergistic for muscle regeneration: TB-500 mobilizes progenitor cells, PEG-MGF stimulates their differentiation into myocytes. Both have overlapping but distinct repair cascades.

PEG-MGF: 100–200 mcg SQ post-training
TB-500: 2–5 mg SQ, 2× per week (loading), then weekly
Timing: Stagger injections by 6–12 hours
Primary benefit: Maximal satellite cell recruitment and myogenic differentiation, injury repair