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№ 052

MGF (Mechano Growth Factor)

Splice variant of IGF-1 produced by muscle in response to mechanical loading and damage. Triggers satellite cell activation. Short half-life, superseded for most use cases by PEG-MGF.

GH-axis
Evidence: Limited

MGF (Mechano Growth Factor): Splice variant of IGF-1 produced by muscle in response to mechanical loading and damage. Triggers satellite cell activation. Short half-life, superseded for most use cases by PEG-MGF. MGF is a splice variant of IGF-1 your muscle makes after damage.

FDA ⓘ
Not approved
WADA
Banned
Typical dose
100-200 mcg sub-q post-workout
Half-life ⓘ
~5-7 minutes
Route ⓘ
Subcutaneous, often near worked muscle
Schedule
Post-workout, 1x daily
In plain English

MGF is a splice variant of IGF-1 your muscle makes after damage. Tells satellite cells to wake up and rebuild. The unmodified version clears in minutes, so it only works locally, most users prefer PEG-MGF for systemic effect.

Status & legalityWhat do these mean? →
Natty? ⓘ
Not natty

IGF-1 derivative. Universally banned in tested sport.

FDA ⓘ
Not approved

Not FDA approved as a drug.

Compounding ⓘ
Category 3

FDA lists mechano growth factor in Category 3 of the 503A nominations: nominated without enough supporting information for FDA to evaluate it. It is not on the 503A list.

WADA ⓘ
Banned (S2)

Falls under the S2 IGF / growth factor category.

Prescribed ⓘ

Not prescribed in conventional medicine.

Who it's for

  • →Lifters experimenting with site-specific muscle anabolism
  • →Post-injury muscle recovery contexts
  • →Researchers preferring short-acting MGF over PEGylated version

What to expect

  1. Week 1

    Acute pumps and fullness in worked muscle.

  2. Week 4

    Subjective recovery improvements. Site-specific tissue responses.

  3. Week 8

    Cycle endpoint reached. Receptor desensitization ramping.

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How it works (mechanism)

Splice variant of IGF-1 produced locally by muscle in response to mechanical loading. Activates satellite cells (muscle stem cells) to proliferate and fuse, the basis of damage-driven hypertrophy. Native form is metabolized in minutes.

Dosing protocol

Members only

Stacks well with

Members only

Side effects

01Hypoglycemia at higher doses
02Localized tissue growth at injection site
03Headache
04Skin sensitivity at site

When NOT to use

  • ⚠Active malignancy
  • ⚠Diabetic retinopathy
  • ⚠Pregnancy / nursing

Bloodwork to monitor

  • • IGF-1 baseline + at week 4
  • • Fasting glucose every 2 weeks

Common mistakes

  • • Treating it as long-acting (it isn't, it's metabolized in minutes)
  • • Confusing it with PEG-MGF (different kinetics)
  • • Long cycles without breaks

What it actually is

MGF, mechano growth factor, is a splice variant of the IGF-1 gene that muscle produces in response to mechanical loading and damage. It is not a separate hormone so much as a locally made, locally acting form of IGF-1 with an extra peptide sequence on the end. Sold for muscle repair, it has a half-life measured in single-digit minutes, which is the practical problem with injecting it.

When muscle is loaded or damaged, the IGF-1 gene is spliced differently to produce this variant. Its distinctive E-domain peptide appears to act on satellite cells — the reserve cells that fuse into muscle fibres to repair and enlarge them — recruiting them to the damaged area. The signal is designed to be short-range and short-lived, produced where it is needed and gone quickly. Injecting it subcutaneously and expecting it to reach and act on a specific muscle is asking a five-minute signal to do something it was never built to do.

Forms, and which is which

Lyophilised powder, subcutaneousHow all use happens

Buyer reconstitutes, usually injecting near a trained muscle immediately post-workout because of the very short half-life.

Verdict: The only form, and the kinetics work against it.

PEG-MGFExtending the half-life

Polyethylene glycol attached to slow clearance, taking the half-life from minutes to hours.

Verdict: Solves the duration problem, at the cost of the locality that was the point.

IGF-1 LR3 or DESSystemic IGF-1 signalling

Different molecules doing a different job. Not interchangeable with MGF despite the shared gene.

Verdict: Same family, different proposition.

Oral or topical MGFNothing

Not absorbed intact as an active dose by either route.

Verdict: Not plausible as described.

What it is claimed to do, graded

Activates satellite cells and aids muscle repairLimited

Supported in cell and animal work, and the underlying biology is real — this is a molecule your own muscle makes for exactly this purpose. Eight human trial records are indexed for the broader mechano growth factor literature, none testing injected MGF for muscle growth.

Builds muscle when injectedNone shown

No controlled human trial. The five-to-seven-minute half-life is the obvious obstacle.

Helps cartilage and connective tissueLimited

A real and growing animal and in-vitro literature, including chondrocyte and periodontal ligament work.

Protects nerve tissueLimited

Shown in models of chemotherapy-induced neuropathy. Model-system evidence.

Acts locally when injected near a muscleNone shown

The core assumption behind how people use it, and it has never been demonstrated in a person.

Grades describe how much human evidence exists for that specific claim, not whether it will work for you or whether it is safe.

Pros and cons

Pros
  • • Genuinely real biology — this is an endogenous signal, not an invented compound
  • • A substantial published literature across muscle, cartilage, heart and nerve
  • • Very short half-life means a mistake clears almost immediately
  • • No hormonal side effects of the kind the GH-axis compounds carry
Cons
  • • The half-life of a few minutes undermines the entire injectable premise
  • • No human trial of injected MGF for muscle
  • • Frequently sold using the general mechano growth factor literature as if it were evidence for the injectable product
  • • Research-chemical supply with unverified identity
  • • Banned in sport as an IGF-1 variant

When to stop

  • • Any hypoglycaemic symptoms
  • • Any new lump or unexplained weight loss
  • • Injection-site reaction that spreads or hardens
  • • Six weeks, on any protocol — nothing supports longer

Interactions

InsulinCaution

IGF-family molecules can lower blood glucose. The risk is smaller than with LR3 and is not zero.

Active or suspected cancerAvoid

IGF-1 signalling drives tumour growth. Untested and serious.

Growth hormoneMonitor

Growth hormone raises your own IGF-1 and its splice variants. No interaction data.

Resistance trainingCompatible

Not an interaction. Mechanical loading is what produces MGF endogenously and is the intervention with actual evidence.

PEG-MGFCaution

Same molecule with different kinetics. Running both is redundant.

Is this for you?

Probably worth reading further if
  • • People who understand they are testing an unproven delivery premise, not a proven compound
Skip it if
  • • You have active cancer or an undiagnosed lump
  • • You are prone to hypoglycaemia
  • • You are pregnant, nursing, or drug-tested in sport
  • • You expect a systemic effect — the molecule clears before it could produce one

The one number

0 human trials of injected MGF for muscle growth, against a half-life of about five minutes
Pepdex evidence index — counts are indexed PubMed records, not deduplicated trials; PubMed query for mechano growth factor

Sources for the claims above

Drug & supplement interactions

  • ⚠Insulin: hypoglycemia risk
  • ⚠Short half-life means fewer chronic interaction concerns
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AI Coach, live sample
Member answer
is 250mcg of bpc enough for a knee injury?
For a knee, is the standard working dose and a solid place to start. The trick with BPC is consistency, give it weeks, not days. , run it , and don't drop below , results tend to fall off under that line. If nothing's moved by week 3, that's when earns its place.
how much bac water for a 10mg reta vial?
is the standard play for a 10 mg reta vial. That gives you , clean unit math across the whole titration: on a 100-unit insulin syringe. Run instead if you want fewer, more concentrated shots. Most people titrate up over , and that mix keeps the numbers cleanest.
what should i track on bloodwork for tirzepatide?
Lipid panel, ALT/AST (liver enzymes), and an A1C, baseline before you start then every 3 months. If you've got metabolic-syndrome history, add fasting glucose and insulin so you can actually watch insulin sensitivity improve. You don't need a big hormone panel for a GLP-1.

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Frequently asked

What is MGF (Mechano Growth Factor)?+
MGF is a splice variant of IGF-1 your muscle makes after damage. Tells satellite cells to wake up and rebuild. The unmodified version clears in minutes, so it only works locally, most users prefer PEG-MGF for systemic effect.
Is MGF (Mechano Growth Factor) FDA approved?+
Not FDA approved as a drug.
Is MGF (Mechano Growth Factor) legal?+
MGF (Mechano Growth Factor) is not FDA-approved, so there is no approved prescription version. Most supply is sold as "research only" by peptide vendors. A compounding pharmacy may only use substances the FDA permits for compounding, and many research peptides are not permitted — do not assume a compounded prescription is available. Possession is generally not criminalized but distribution without authorization may be. Verify local laws.
Is MGF (Mechano Growth Factor) banned by WADA?+
MGF (Mechano Growth Factor) is on the WADA prohibited list under Banned (S2). Falls under the S2 IGF / growth factor category.
Are you still natty after taking MGF (Mechano Growth Factor)?+
No. IGF-1 derivative. Universally banned in tested sport.
Do doctors prescribe MGF (Mechano Growth Factor)?+
Not prescribed in conventional medicine.
What's the typical dose of MGF (Mechano Growth Factor)?+
Dosing depends on your goal, experience, and tolerance. The full MGF (Mechano Growth Factor) protocol (dose, frequency, and how to titrate) is in the members section on the entry page.
What are the side effects of MGF (Mechano Growth Factor)?+
Common side effects include: Hypoglycemia at higher doses; Localized tissue growth at injection site; Headache; Skin sensitivity at site. Less common effects and full safety details are on the entry page.
How long until MGF (Mechano Growth Factor) starts working?+
Acute pumps and fullness in worked muscle.
What can you stack with MGF (Mechano Growth Factor)?+
MGF (Mechano Growth Factor) is commonly combined with complementary compounds. The full stacking protocol (what to pair, dosing, and timing) is in the members section on the entry page.
Where do people get MGF (Mechano Growth Factor)?+
Pepdex does not sell, ship, or recommend suppliers. MGF (Mechano Growth Factor) is not FDA-approved; prescription versions require licensed clinical care, and "research only" markets carry real legal and quality risks. /coa explains how to verify a Certificate of Analysis and /guides/scam-vendor-spotting covers the red flags.

Common questions about MGF (Mechano Growth Factor)

Tracked alongside MGF (Mechano Growth Factor)

Same goal, different aisle — each graded on its own evidence in the Pepdex catalog.

MK-677 →
the oral secretagogue these peptides get compared to constantly
Creatine →
the strongest-evidence performance supplement in the catalog
Glycine →
sleep quality drives GH pulses; this is the benign first option
Melatonin →
same reason — the sleep window is the GH window

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