PEGylated IGF-1 splice-variant E-domain peptide construct

PEG-MGF

aka PEGylated mechano growth factor · Mechano growth factor pegylated

Evidence grade
Grade D: Preclinical only
for muscle recovery and growth
User score too few reports (7) needs ≥ 10 reports
US FDA Not approved checked 2026-11-13
WADA 2026 Prohibited (S2.3) at all times · checked 2026-11-13
EU No data · checked 2026-11-13

User reports

approximate — combined from two independent Reddit reads

Men 45–60

1 man aged 45–60

small sample · n = 1

Outcome unclear 1 of 1

Side effects none reported

Stopped 0 of 1 Used with other compounds 1 of 1

All men

1 man

small sample · n = 1

Outcome unclear 1 of 1

Side effects none reported

Stopped 0 of 1 Used with other compounds 1 of 1

Everyone

7 people

small sample · n = 7

Outcome mixed 2 of 7 · positive 2 of 7 · unclear 2 of 7 · no effect 1 of 7

Benefits muscle 2 of 7 · injury healing 1 of 7 · joints / tendons 1 of 7 · strength 1 of 7

Side effects fatigue 1 of 7 · injection site 1 of 7 · other 1 of 7

Stopped 0 of 7 Used with other compounds 3 of 7

User reports are anecdata, not evidence: self-selected, unverified, often combined with other compounds.

In their words

  • “I had just finished a cycle of IGF1-LR3 (40mcg every other day) and PEG-MGF (400mcg on opposite days) for 4 weeks.”

  • “I just used it for injured knee tendons and it healed them very effectively”

  • “I've been using it for a strain and haven't seen much difference.”

  • “I take this 30 mins post workout. How long after administering is it suggested to eat food?”

Read summaries and method notes

Read 1. One verified 56-year-old male reported a four-week PEG-MGF cycle, but it was combined with IGF-1 LR3 and testosterone therapy, leaving the PEG-MGF-specific outcome unclear. Among seven coded users overall, isolated claims included improved tendon recovery or muscle growth, alongside reports of no noticeable benefit or short-lived training effects. Some people described discomfort associated with intramuscular administration, and one described a rebound in training performance afterward. Reports often blur PEG-MGF with unmodified MGF or combine it with other growth-related compounds. The evidence is particularly unreliable because the number of usable accounts is very small and compound identity or purity was not independently verified.

Read 2. No man aged 45–60 and no stated man; one self-reporter in total, who takes it 30 minutes post-workout and asked about meal timing without reporting any outcome. Three of four threads were prospective dosing questions. No conclusions possible.

Note 1. The 56M user's outcome was unclear, not a confirmed no-effect result; the quote stance denotes absence of demonstrated efficacy rather than his stated verdict. Plain-MGF-only discussion was excluded. Some accounts mention both PEG-MGF and other growth factors without separately measuring outcomes. No evidence of an independently confirmed product identity or standardized exposure was found. Counts represent a selected set of verifiable reports.

Note 2. Extremely sparse: 3 of 4 threads were questions, and three r/steroids seed threads were not retrievable.

Each read counted people independently. Overlap between the two reads is estimated from shared threads and removed; counts are approximate. How we count.

Summary

PEG-MGF is a PEGylated synthetic IGF-1 splice-variant E-domain peptide construct, distinct from naturally expressed IGF-1 splice transcripts, their precursor proteins and non-PEG synthetic MGF. Cell experiments on the MGF E-domain reported myoblast proliferation and reduced terminal differentiation, but this does not establish satellite-cell-mediated clinical repair from injected PEG-MGF. A longer human half-life from PEGylation was not verified. It is discussed for muscle recovery, but human treatment efficacy remains unestablished.

Safety

  • FDA warns of potential immunogenicity with certain routes
  • Peptide-related impurities and active-ingredient characterization are concerns
  • FDA identified no human exposure data for drug products containing PEG-MGF
  • Human pharmacokinetics, contraindications and long-term safety not found

From labels, regulators and trials. No signal in small studies ≠ safe.

Evidence D muscle recovery and growth

D stands. No human exposure data at all (FDA says the same); related lab findings conflict.

Human trials · 0

No human trials found for the marketed use.

Dose ranges

Reported ranges from labels and studies, with context. Not a recommendation.

No data.

Editorial ratings EDITORIAL

Editors’ judgement, 0–5. Opinion, not data; separate from grade and user score.

  • Safety 3.5 out of 5
  • Sleep 2.5 out of 5
  • Recovery not rated —
  • Cognitive not rated —

Sources

  1. fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-pres
  2. wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
  3. fda.gov/advisory-committees/advisory-committee-calendar/july-23-24-2026-meeting-pharmacy-c
  4. pubmed.ncbi.nlm.nih.gov/12095637/
  5. pubmed.ncbi.nlm.nih.gov/24253050/
  6. pmc.ncbi.nlm.nih.gov/articles/PMC2342624/
  7. fda.gov/media/94155/download

Reddit threads read · 8

3 further sources on commercial or non-primary hosts not listed.

Research checked 2026-11-13.