PEG-MGF
PEG-MGF is a synthetic pegylated analog of Mechano Growth Factor, a splice variant of IGF-1 your skeletal muscle produces in response to mechanical stress or injury. Native MGF degrades in plasma within minutes. PEGylation extends its half-life to 24 to 72 hours, enabling systemic administration and preclinical investigation across muscle regeneration, tissue repair, bone healing, and cardiac recovery. No human clinical trials have been completed for PEG-MGF in any indication.
Important status notice. PEG-MGF is not FDA approved for any therapeutic use. PEG-MGF was previously classified as a Category 2 bulk drug substance under the FDA's interim 503A list. That Category 2 designation was removed on April 22, 2026, after the nominator withdrew the nomination. Removal from Category 2 does not authorize compounding — PEG-MGF is not on the 503A bulks list. The FDA will consult the Pharmacy Compounding Advisory Committee (PCAC) before the end of February 2027 on potential inclusion of PEG-MGF on the 503A bulks list.
WADA Status. PEG-MGF is prohibited under WADA S2: Peptide Hormones, Growth Factors, Related Substances, and Mimetics. IGF-1 and all its variants and analogs are explicitly covered. Prohibited at all times, in and out of competition, in every WADA-regulated sport.
.webp)
.webp)
Overview
MGF is produced by alternative splicing of the IGF-1 gene in response to mechanical load or tissue damage. Its primary function is to activate quiescent satellite cells, the muscle stem cells your body uses to repair damaged fibers, and expand the pool of myogenic precursors before mature IGF-1 drives their differentiation. The MGF E-peptide carries autonomous biological activity independent of the IGF-1 receptor, making PEG-MGF a coordinator of the full repair cascade rather than simply an anabolic stimulus.
Native MGF has a plasma half-life of approximately five to seven minutes. PEGylation, the attachment of polyethylene glycol chains, extends this to approximately 24 to 72 hours, improves solubility, and enables subcutaneous administration with meaningful tissue exposure. Detection in plasma and urine is possible using specialized assay methods. WADA tests for MGF and its analogs in anti-doping programs. The preclinical research base is consistent across multiple tissue systems. No human clinical data exists.
Chemical structure & Properties
- Core Sequence (24 aa): Tyr-Gln-Pro-Pro-Ser-Thr-Asn-Lys-Asn-Thr-Lys-Ser-Gln-Arg-Arg-Lys-Gly-Ser-Thr-Phe-Glu-Glu-Arg-Lys
- Molecular Formula (Core): C₁₂₁H₂₀₀N₄₂O₃₉
- Molecular Weight: ~2,867 Da core; ~4,000 to 6,000 Da with PEG conjugation
- Origin: Synthetic analog of MGF (IGF-1Ec), C-terminal fragment of IGF-1
- Half-Life (Native MGF): ~5 to 7 minutes in plasma
- Half-Life (PEG-MGF): ~24 to 72 hours
- Route: Subcutaneous injection
- Storage: Lyophilised powder; 2°C to 8°C before reconstitution
- WADA Status: Prohibited, S2 (Peptide Hormones, Growth Factors, Related Substances, and Mimetics)
Mechanism of Action
PEG-MGF exerts its biological effects through multiple interconnected molecular mechanisms rooted in IGF-1 splice variant biology:
Areas Investigated in
the Research Literature
Current Clinical Evidence
Safety Considerations
Regulatory Status and Legal Considerations
Regulatory information current as of 28 August 2026. This is a summary, not legal or medical advice, and status can change.
FDA Status
- Not FDA approved for any therapeutic indication
- Previously Category 2 on the 503A interim list; that designation was removed on April 22, 2026
- Removal from Category 2 does not authorize compounding
- PCAC consultation expected before February 2027 on potential 503A bulks list inclusion
- Sourcing of unapproved research compounds is unregulated, and identity and purity are not assured.
WADA Status
- Category: S2, Peptide Hormones, Growth Factors, Related Substances, and Mimetics
- IGF-1 and all variants, splice variants, and analogs explicitly covered
- Prohibited at all times, in and out of competition, every WADA-regulated sport
- Urine and blood testing available for anti-doping purposes
Legal Availability
- Research use legal in the United States for non-competing adults
- Not approved as a therapeutic, which is a distinct question from legality
- Products sold outside licensed channels carry sterility and purity risks that no authority audits
What the evidence supports
PEG-MGF is a pegylated form of mechano growth factor, an IGF-1 splice variant expressed by muscle in response to mechanical loading. Pegylation extends its half-life substantially, and animal work has reported effects on satellite cell activation and muscle repair.
No human clinical data exists. There are no controlled trials, no established dosing, and no safety record in people. PEG-MGF is not FDA approved and is prohibited under WADA. This page summarizes the preclinical research and nothing further.
PEG-MGF SCIENTIFIC
DATA SUMMARY
About this library
This library is published for education. It summarizes published research on compounds studied in this field. Many have no approved medical use, and several cannot lawfully be compounded in the United States. The presence of a page here does not mean Paragon offers that compound. Nothing on these pages is an offer to treat.
This page is general education about a compound studied in this field. Nothing here is medical advice, a recommendation, or an offer to prescribe or supply. A page appearing in this library does not mean Paragon Sports Medicine offers that compound.
Disclaimer: This information is provided for educational purposes only and does not constitute medical advice. PEG-MGF is not approved by the FDA or any major regulatory authority for any therapeutic indication. It is prohibited under WADA S2 and must not be used by anyone competing in a WADA-regulated sport. Its 503A compounding status changed on April 22, 2026, when the FDA removed PEG-MGF from Category 2. A PCAC advisory consultation is expected before the end of February 2027 regarding potential inclusion of PEG-MGF on the 503A bulks list. Patients should consult with a qualified clinician and ensure regulatory compliance before considering any use of PEG-MGF.
Statements on this page have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Many peptides described here are not FDA approved for the uses discussed, and some cannot lawfully be compounded in the United States. Nothing on this page is medical advice or a recommendation for any individual. Whether any therapy is appropriate depends on your history, your laboratory results, and a clinical evaluation. Individual results vary. This page is published for education. Use of this site does not create a physician-patient relationship.