PEG-MGF

Definition

Mechano growth factor is a splice variant of insulin-like growth factor 1, designated IGF-1Ec, whose expression rises in skeletal muscle after mechanical loading and damage. It is a product of the body's own response to exercise, and its proposed role is in the activation of satellite cells and local repair ^[1].

PEG-MGF is a pegylated synthetic version, sold on the premise that injecting the molecule reproduces what loading induces. This index tracks the injectable product; the underlying biology and the product are different objects, and the record below keeps them apart.

Evidence

The biology is real and the review literature treats it carefully, including the caution that the peptide is a putative rather than an established product of the gene's expression in the form usually claimed ^[1]. A 2026 review of approved and unapproved peptide therapies in musculoskeletal injury and athletic performance places this compound among the unapproved ^[2].

The trial-type count is the trap. Across five name variants PubMed returns 236 indexed records, 134 carrying the Humans subject heading, 12 under the clinical-trial publication type, and 11 under the randomized-controlled-trial type ^[3]. Twelve looks like a trial record. It is not one.

All twelve were opened and read, and not one administers the peptide to anyone. Every one measures a participant's own IGF-1Ec or mechano growth factor expression after an intervention that is not the peptide: resistance exercise at varying intensities, neuromuscular electrical stimulation after abdominal surgery, therapeutic ultrasound, recombinant growth hormone, high-intensity interval training in heart failure, testosterone therapy in older men, and pharmacological hypogonadism ^[3]. The count is a count of exercise physiology. The number of human records in which PEG-MGF was given to a person and an outcome measured is zero.

Lawful access

There is no lawful United States supply route. Mechano growth factor pegylated left Category 2 of FDA's interim section 503A bulks list in April 2026 when the nomination was withdrawn by its nominators, and it was not added to Category 1 ^[4].

The list published on May 14, 2026 draws a distinction worth keeping. PEG-MGF appears in no category. The unpegylated substance, mechano growth factor (MGF), appears in Category 3 — the category for substances nominated without adequate support, which is neither a permission nor a safety finding but a statement that the nomination did not carry enough information to evaluate ^[4]. Two closely related substances therefore sit in two different places on the same list, and neither may be compounded.

FDA's published finding for the pegylated form matches this index's census: the agency has not identified any human exposure data on drug products containing PEG-MGF administered via any route of administration ^[5]. In April 2020 it also warned a compounding pharmacy that products compounded using PEG-MGF and twenty-one other substances were not eligible for the exemptions in section 503A(a) ^[6]. Material sold under this name is research-use-only chemical supply; see research-only.

Related molecules

PEG-MGF is filed with the growth factor fragments alongside AOD-9604, which shares its shape exactly: a fragment of a growth-axis protein, marketed for a body-composition effect, with a regulatory record and almost no human one. The human trial record prints both counts, and the nomination tracker files both by what became of the nomination.

Elsewhere in this index