Mechano growth factor is a peptide made from a variant of the IGF-1 gene, which research proposes muscle produces locally after mechanical damage. The product sold as "MGF" is a synthetic version without the PEGylation used in PEG-MGF, so it is described as clearing from the body much faster.

It is not an FDA-approved drug. It is sold as a research chemical, and no regulator checks that a vial matches its label. WADA names it explicitly, with PEG-MGF, under section S2.3, and it is banned at all times in sport.

Research peptides

MGF: What It Is, Dosage and Side Effects

MGF (mechano growth factor): the non-PEGylated form, why it differs from PEG-MGF, common research dosing, and legal status.

Written bySebastian Hunter, Founder and EditorI'm a 42-year-old senior advisor and distance runner who came to peptides as a sceptic. I'm not a doctor: I read the research, run my own experiment and keep honest notes. Read full bio

Published September 28, 2026Updated October 1, 2026

The short version

MGF is the unmodified (non-PEGylated) form of mechano growth factor, a peptide related to IGF-1 that research proposes muscle makes locally after training damage. Sources describe it as cleared within minutes, which is why a longer-acting product, PEG-MGF, exists. No completed human trial has tested either form. It is not FDA-approved and is banned at all times in sport.

MGF is the short-acting, non-PEGylated form; PEG-MGF is a separate product built to last longer.
Sources describe unmodified MGF as cleared within minutes, against roughly 48-72 hours for PEG-MGF.
No completed human trial has tested injected MGF for any outcome; the research is animal and cell work.
Banned at all times in sport under WADA section S2.3, which names "Mechano growth factors" explicitly.

MGF at a glance

What it is: Synthetic peptide corresponding to a splice variant of the IGF-1 gene, without the PEGylation used in the related product PEG-MGF
Main use: Marketed to consumers as a peptide injected directly into a trained muscle immediately after exercise, for local muscle repair and growth. No completed human trial has tested it for this or any outcome.
Also called: Mechano Growth Factor, IGF-1Ec, Non-pegylated MGF
Size: 24 amino acids Details
Evidence: Animal / lab only
US status: Research use only
Half-life: Described by vendor and community sources as on the order of minutes, unlike the PEGylated version; no published human pharmacokinetic study establishing a figure was located.
How it is taken: Intramuscular injection
Common protocol: 100-400 mcg, Immediately post-workout, 2-3 times a week (training days only), for 4-8 weeks (common practice, not trial-established) Dosage chart

MGF and PEG-MGF are different products, even though vendors sell them side by side. Dosing: what research-channel sources describe as common practice.

What is MGF?

Mechano growth factor (MGF) is the name researchers gave to a peptide made from a variant (splice variant) of the IGF-1 gene. Animal and cell research proposes that muscle makes this variant locally after mechanical damage, separately from the IGF-1 the liver releases into the blood. “MGF” as sold to consumers is a synthetic version of that peptide without the PEGylation used in PEG-MGF.

That missing PEGylation is why two products exist. Vendor and community sources describe unmodified MGF as cleared from the body within minutes, so any effect is tied to where and when it is injected. PEG-MGF’s modification slows clearance to roughly 48-72 hours, by the same sources, trading a fast local signal for a slower, wider one. Neither figure comes from a published human study.

MGF structure

Length: 24 amino acids
Sequence: YQPPSTNKNTKSQRRKGSTFEERK
Modifications: The 24 C-terminal residues of the E domain of human IGF-1Ec (UniProt P05019 isoform 4).

This is the natural human sequence. Products sold as MGF are not verified to match it, and some published MGF peptides use rodent or modified sequences.

Sequence checked against Journal of Tissue Engineering and Regenerative Medicine (2018), via PubMed.

MGF benefits: what the research shows

No human trial has given MGF to people and measured an outcome. The research is the same animal and cell work on the natural gene variant that underpins PEG-MGF’s page. It was designed to describe local gene activity after muscle injury, not to test a synthetic peptide in a person. No adequately sized, controlled human trial has tested MGF for muscle growth, recovery or any other marketed outcome.

Animal / lab only

Studied in cells or animals. No controlled trials in humans. The evidence for MGF's proposed biology is animal and cell-culture research into a natural IGF-1 splice variant. No completed human trial has tested the synthetic, non-PEGylated peptide sold as MGF for any outcome.

MGF dosage

The common MGF dose is 100-400 mcg, Immediately post-workout, 2-3 times a week (training days only). From a 2 mg vial mixed with 2 mL of bacteriostatic water, 250 mcg is 25 units (0.25 mL) on a U-100 insulin syringe.

See the full MGF dosage chart →

Research-community sources describe roughly 100-400 mcg injected into or near the trained muscle straight after a workout, 2-3 times a week, for 4-8 week cycles. The schedule is built around MGF’s minutes-long clearance. That is common practice, not a tested dose. Full sourcing, and how it differs from PEG-MGF’s twice-weekly schedule: MGF dosage.

MGF side effects

There is no established human side-effect profile, because no completed human trial has tested MGF.

MGF and PEG-MGF act on the same pathway as IGF-1, which raises a general concern about insulin sensitivity and growth signalling. That is inferred from the shared mechanism, not found in a study of this peptide; treat it as a reason for caution, not a measured risk. Injecting straight into a freshly trained muscle also carries local injection risks that a shot under the skin does not.

Is MGF legal?

US legal status - Research use only

Sold for laboratory research use only. Not approved by the FDA for human use, and cannot be lawfully marketed as a supplement or a medicine. Products sold this way are not made to pharmaceutical quality standards, and their contents are not verified by anyone.

Not FDA-approved for anything. PEG-MGF was nominated to FDA’s list of bulk substances that may present significant safety risks in compounding, over a possible immune-reaction risk by some routes. That nomination was withdrawn rather than finalised, so it is not on the active restricted list.
Sold to consumers as a research chemical, usually labelled not for human use.
WADA’s Prohibited List, section S2.3, names “Mechano growth factors (MGFs)” explicitly, banned at all times, alongside PEG-MGF and IGF-1 analogues.

PEG-MGF - the PEGylated, longer-acting version of this same peptide idea
CJC-1295 - a GHRH analogue often marketed alongside growth-factor peptides
HGH 191AA - upstream growth hormone, which MGF is downstream of in the GH-IGF-1 idea
Research peptides and the law

Regulatory changes for this compound and others, as they happen: US peptide regulation tracker.

How MGF compares

Growth hormone and growth factors. Doses for unapproved compounds are common practice, not trial-established. All growth hormone and muscle peptides →

Compound	Main use	Evidence	Usual dose	US status
HGH 191AA	Marketed to consumers for body recomposition, recovery and anti-aging in adults who do not have a diagnosed growth hormone deficiency. The identical molecule, somatropin, is FDA-approved by prescription for defined deficiency and wasting conditions - see the "Where approved somatropin fits" section on the main guide for that distinction.	Limited human data	333-1333 mcg, Once daily (split into a morning and evening dose above roughly 3 IU/day), subcutaneous	Research use only
IGF-1 LR3	Originally engineered as a laboratory reagent - an IGF-1 variant with reduced binding to IGF-binding proteins, used to study IGF-1 signalling in cell culture. Sold to consumers as a research chemical for muscle growth, a use with no controlled human trial behind it.	Animal / lab only	20-50 mcg, once daily	Research use only
IGF-1 DES	Originally isolated and studied as a naturally occurring IGF-1 fragment in laboratory pharmacology, used to probe IGF-1 receptor signalling with reduced interference from binding proteins. Sold to consumers as a research chemical for localised, site-specific muscle growth, a use with no controlled human trial behind it.	Animal / lab only	20-120 mcg, on training days only, about 4-5 times a week, not on rest days	Research use only
MGF	Marketed to consumers as a peptide injected directly into a trained muscle immediately after exercise, for local muscle repair and growth. No completed human trial has tested it for this or any outcome.	Animal / lab only	100-400 mcg, Immediately post-workout, 2-3 times a week (training days only)	Research use only
PEG-MGF	Marketed to consumers for muscle repair and growth after resistance training. Never approved for human use; FDA states it has identified no human exposure data on it by any route.	Animal / lab only	200-400 mcg, 2-3 times a week, post-workout	Research use only
Follistatin	The body's own brake on activin and myostatin signalling, studied academically as a gene-therapy payload for muscle-wasting disease. Sold separately, as an injected research-chemical protein, for grey-market muscle-building use that its own human trials have never tested.	Animal / lab only	100-500 mcg, 2 to 4 times a week	Research use only

Where to buy MGF for research

Each vendor is checked against my vendor checklist.

1.Next Level PharmFeatured
2 mg vial
- No FDA warning letter found
- Names its testing lab
- Batch COAs published
- Takes card payment
$29.99as of 3 October 2026
View product →My Next Level Pharm review

See all vendors and how they compare →

Common questions

What is the difference between MGF and PEG-MGF?

They are the same peptide idea in two forms. MGF isn't PEGylated, and sources describe it as cleared within minutes, so its effect stays where and when it is injected. PEG-MGF has polyethylene glycol chains attached to slow clearance to roughly 48-72 hours, by vendor and community description. No published human study pins down either figure; the PEG-MGF page has the full comparison.

What is the usual MGF dose?

Research-community sources describe roughly 100-400 mcg injected into or near the trained muscle straight after a workout, 2-3 times a week, for 4-8 week cycles. That is common practice, not a tested dose. The dosing page has the full sourcing.

What are the side effects of MGF?

There is no established human side-effect profile, because no completed trial has tested MGF in people. Because it acts on the same pathway as IGF-1, there is a general concern about insulin sensitivity and growth signalling. That is inferred from the mechanism, not a documented reaction.

Who should not use MGF peptide?

Competitive athletes, at minimum: WADA bans it at all times. Beyond that, I found no study defining who should avoid it, and no published human safety data. Because it acts on the IGF-1 growth pathway, caution about insulin sensitivity and growth signalling applies too, as an inference from the mechanism rather than a documented risk group.

Where do you inject MGF peptide?

Common practice, not a tested method, is to inject into or near the trained muscle within minutes of finishing a workout, because sources describe MGF as cleared within minutes. One source also describes injecting under the skin of the abdomen or thigh. The MGF dosage page has the full sourcing.

Can MGF stimulate muscle growth?

It hasn't been tested for muscle growth in people. In cell studies the evidence conflicts: early work reported that the MGF peptide boosted muscle precursor cells, but researchers at two pharmaceutical companies couldn't reproduce that in mouse or human muscle cells. Neither result shows it builds muscle in a person.

References (1 sources)

Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.

1.WADA Prohibited List, section S2.3 - Growth Factors and Growth Factor Modulators, naming "Mechano growth factors (MGFs)" explicitly (national anti-doping agency mirror, PDF).- Jamaica Anti-Doping Commission (mirroring the World Anti-Doping Agency Prohibited List)regulatory