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Growth Hormone — IGF-1 Splice Variant✓ FDA Approved

PEG-MGF

Also known as: PEGylated Mechano Growth Factor · PEG-MGF

MW

2948.15 Da

Amino Acids

24 AA

Half-Life

24-48 hours (PEGylated)

Route

SubQ, IM

Mechanism of Action

PEG-MGF (PEGylated Mechano Growth Factor) is the PEGylated form of MGF, a splice variant of IGF-1 produced specifically in response to mechanical stress (exercise, injury).

MGF vs IGF-1Ea: Standard IGF-1 (IGF-1Ea) promotes myoblast differentiation — turning satellite cells into mature muscle fibers. MGF (IGF-1Ec in humans) specifically promotes satellite cell PROLIFERATION — expanding the pool of muscle stem cells before they differentiate. These are sequential steps: MGF expands the satellite cell pool, then IGF-1Ea differentiates them.

PEGylation: Native MGF has a half-life of minutes. PEG (polyethylene glycol) attachment extends this to hours, making it practical for injection.

SITE-SPECIFIC: Most effective when injected directly into mechanically stressed (recently trained) muscle tissue, where it works in concert with the local MGF/IGF-1 splice variant response to exercise.

Dosing Protocol

Low Dose

███ – ███ mcg/day

Standard Dose

███ mcg/day

High Dose

███ – ███ mcg/day

Dosing protocols are for paid members

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Frequency

2–3x/week, post-workout into trained muscle.

Half-Life

24-48 hours (PEGylated)

Reconstitution Guide

Full reconstitution protocol with BAC water volumes, concentration math, and units-to-draw per dose is available on the Clinical plan.

Unlock reconstitution guide →

Clinical Warnings

Site-specific IM injection required — not SubQ.

Infection risk at injection site.

No human RCT data.

PEG immune reactions possible with repeated use.

Must be used post-exercise.

WADA prohibited.

Contraindications

Absolute

Active cancer

Pregnancy

Relative Cautions

Diabetes

History of cancer

Side Effect Profile

Mild

  • Injection site swelling
  • Mild hypoglycemia

Moderate

  • Localized pain
  • Fatigue
  • Headache

Severe (Rare)

  • Cancer proliferation risk
  • Severe hypoglycemia

Synergistic Peptides

IGF-1 LR3CJC-1295BPC-157

Common Stacks

IGF-1 LR3

CJC-1295

Research Status

PRECLINICAL. PMID 12578347 (Hill 2003): MGF splice variant satellite cell activation. PMID 21820400 (Matheny 2011): PEGylation effect on half-life and muscle repair. No human RCTs for PEG-MGF.

Frequently Asked Questions

How does PEG-MGF work?

PEG-MGF (PEGylated Mechano Growth Factor) is the PEGylated form of MGF, a splice variant of IGF-1 produced specifically in response to mechanical stress (exercise, injury). MGF vs IGF-1Ea: Standard IGF-1 (IGF-1Ea) promotes myoblast differentiation — turning satellite cells into mature muscle fibers. MGF (IGF-1Ec in humans) specifically promotes satellite cell PROLIFERATION — expanding the pool of muscle stem cells before they differentiate. These are sequential steps: MGF expands the satellite

What is the standard dose of PEG-MGF?

PEG-MGF dosing protocols are available with a ClinPep Clinical subscription. Dosing varies by indication and patient factors — consult a licensed healthcare provider. General frequency: 2–3x/week, post-workout into trained muscle.

What is the half-life of PEG-MGF?

The half-life of PEG-MGF is 24-48 hours (PEGylated). This determines optimal dosing frequency and timing.

Who should not use PEG-MGF?

PEG-MGF is absolutely contraindicated in: Active cancer; Pregnancy. Use with caution in: Diabetes; History of cancer.

What are the side effects of PEG-MGF?

Common mild side effects include: Injection site swelling, Mild hypoglycemia. Moderate effects: Localized pain, Fatigue, Headache.

What peptides stack well with PEG-MGF?

PEG-MGF is commonly stacked with: IGF-1 LR3, CJC-1295, BPC-157.

How do you reconstitute PEG-MGF?

PEG-MGF is reconstituted with bacteriostatic water. Exact volumes, concentrations, and units-to-draw calculations are available in the ClinPep Clinical plan. Always follow your compounding pharmacy's instructions.

How long should you cycle PEG-MGF?

PEG-MGF cycle protocols vary by indication. Detailed cycle length, on/off schedules, and monitoring guidelines are available with ClinPep Clinical access. Consult your healthcare provider for personalized cycling guidance.

References & Citations

10 PubMed studies · 3 clinical trials

A cross-sectional study of urinary sodium, cardiac remodeling, and the mediating role of insulin-like growth factor-1: Insights from the UK Biobank.

Yan Dingyi, Gao Dengfeng, Yuan Miao. Medicine. 2025

PubMed: 41398822DOI ↗C — Research Article

High sodium intake is a known risk factor for cardiovascular disease, but its precise relationship with cardiac remodeling and the potential mediating role of insulin-like growth factor-1 (IGF-1) rema

Long-term clinical control in acromegaly patients with postoperative discordant nadir growth hormone during oral glucose tolerance test and insulin-like growth factor 1 levels: a retrospective observational study and literature review.

Ishida Tomohisa, Kawaguchi Tomohiro, Ogawa Yoshikazu, Endo Hidenori. Langenbeck's archives of surgery. 2025

PubMed: 41369695DOI ↗C — Research Article

Postoperative evaluation in patients with acromegaly typically involves measuring insulin-like growth factor 1 (IGF-1) levels and assessing growth hormone (GH) suppression via an oral glucose toleranc

Drug-induced polycystic ovary syndrome: a real-world pharmacovigilance study based on the FAERS database.

Zhang Huiping, Di Man, Wang Yu, Ma Yingying et al.. Frontiers in endocrinology. 2025

PubMed: 41367917DOI ↗C — Research Article

Previous studies have shown an association between polycystic ovary syndrome (PCOS) and the use of various medications. However, there is still a lack of systematic research exploring this relationshi

Association of serum myokine levels with rapid degeneration in skeletal muscle quality following allogeneic hematopoietic stem cell transplantation.

Murao Masanobu, Hamada Ryota, Kanda Junya, Kondo Tadakazu et al.. Nutrition (Burbank, Los Angeles County, Calif.). 2026

PubMed: 41317606DOI ↗C — Research Article

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) causes rapid deterioration of physical function; therefore, understanding the changes in skeletal muscle quantity and quality and identif

IGF Pathway Components as Potential Biomarkers in Gastric Cancer.

Ceylaner Betul, Sahin Furkan, Yildiz Anil, Tastekin Didem et al.. International journal of molecular sciences. 2025

PubMed: 41303367DOI ↗C — Research Article

Gastric cancer is one of the leading causes of cancer-related deaths worldwide, and due to its late-stage diagnosis, the prognosis is poor. Therefore, researching biomarkers that can be used in early

rFIP-GMI Suppresses IGF-1-Induced Invasion and Migration in Breast Cancer Cells via PI3K/Akt/β-Catenin Inhibition.

Liao Wen-Ling, Wu Yu-Ying, Liu Yu-Fan, Lan Pei-Chi et al.. Drug development research. 2025

PubMed: 41294378DOI ↗C — Research Article

Insulin-like growth factor-1 (IGF-I) promotes breast cancer (BC) progression by activating the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which enhances invasion and migration through β-c

Mechanical growth factor inhibited syndesmophyte formation and the progression of osteoarthritis and ankylosing spondylitis-like symptoms in HLA-B27/Hu-β2m transgenic rats.

Moro Abu, Qin Hongyu, Yuan ShuangShuang, Li Hao et al.. Arthritis research & therapy. 2025

PubMed: 41272763DOI ↗C — Research Article

Studies have documented that exercise programs have symptomatic relief benefits for ankylosing spondylitis patients. It has also been reported that MGF (Mechanical/Mechano Growth Factor) and related g

Normative data for insulin-like growth factor-1 and insulin-like growth factor binding protein-3 and their determinants in healthy adult males from india: the INDIIGo study.

Shah Ravi, Bansal Dipika, Rastogi Pulkit, Sachdev Suchet et al.. Scientific reports. 2025

PubMed: 41271899DOI ↗C — Research Article

The INDIIGo study aimed to establish normative data for serum insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) in adult Indian males, addressing the pauc

Registered Clinical Trials

QUILT-2.017: Phase 1b/2 Study of AMG 479 in Combination With Paclitaxel and Carboplatin for 1st Line Treatment of Advanced Squamous Non-Small Cell Lung Cancer

NCT00807612TERMINATEDPHASE1, PHASE2

Understanding Cerebral Blood Flow Dynamics for Alzheimer's Disease Prevention Through Exercise

NCT06584656COMPLETEDNA

Lifestyle Physical Activity and Cognitive Training Interventions

NCT04556305COMPLETEDNA

Symptom Indications

Muscle injuryMuscle wastingPoor recoveryMuscle growth

Full Clinical Access

Complete PEG-MGF Protocol

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This information is for educational and research reference purposes only. ClinPep does not provide medical advice, diagnosis, or treatment recommendations. All protocols should be reviewed by a licensed healthcare provider.