MEDICAL DISCLAIMER: Educational research guidelines only. Lyophilized peptides are investigational chemical compounds and are NOT approved for human consumption, diagnosis, or therapy. Consult a licensed physician before any research application.
MGF Dosage Chart, Schedule & Reconstitution Protocol
Quickstart Highlights
MGF (Mechano Growth Factor) is the IGF-1Ec splice variant of the IGF-1 gene, produced locally in skeletal muscle in response to mechanical loading and damage. It binds a still-incompletely-characterised receptor distinct from the canonical IGF-1R, activating satellite cell proliferation, myoblast recruitment, and local repair signalling. The synthetic research peptide reproduces the unique E-domain C-terminal sequence of IGF-1Ec and is used to study local muscle regeneration, satellite cell activation, and tissue repair. Native MGF in vivo has an extraordinarily short half-life (minutes) because it acts as an autocrine/paracrine signal at the site of mechanical stress rather than a systemic hormone. Researchers therefore administer it by direct intramuscular injection close to the target tissue. It has no FDA approval and is supplied strictly as a research chemical. Goldspink (J Anat 1999, J Musculoskelet Neuronal Interact 2003) characterised the splice variant and its role in load-induced hypertrophy[1].
Reconstitute: Add 3 mL bacteriostatic water → 1.67 mg/mL concentration.
Easy measuring: At 1.67 mg/mL, 1 unit = 0.01 mL = 0.0167 mg (17 mcg) on a U-100 insulin syringe.
Storage: Lyophilized frozen; reconstituted refrigerated; avoid repeated freeze–thaw.
Half-life: Approximately 5-7 minutes systemically; designed by nature as a local paracrine signal, not a circulating hormone, requiring intramuscular site-of-action dosing[1].
Mechanism class: IGF-1Ec splice variant acting on satellite cells and myoblasts through a non-canonical receptor; distinct from IGF-1R signalling of native IGF-1 and LR3[1].
Administration: Local intramuscular injection adjacent to the target tissue because the molecule is cleared too rapidly for systemic exposure to be useful.
Comparison: PEG-MGF is the pegylated long-acting variant developed precisely because native MGF cannot survive systemic circulation long enough for whole-body research dosing.
Quick Protocol Navigation
Reconstitution Instruction & Mixing Step-by-Step
Lyophilized powder must be reconstituted carefully. Agitating peptide chains can shear disulfide bonds and render the peptide biologically inert.
Draw 3.0 mL bacteriostatic water with a sterile syringe.
Inject slowly down the vial wall; avoid foaming.
Gently swirl/roll until dissolved (do not shake).
Inject slowly; wait a few seconds before withdrawing the needle.
Do not aspirate for subcutaneous injections; inject slowly and steadily[7].
Interactive MGF Syringe Calculator
Currently visualizing the 5 mg vial reconstituted with 3 mL bacteriostatic water. Adjust the target dose to dynamically render syringe units.
Reconstitution Calculation: 5mg dry powder in 3mL water yields 1.67 mg/mL. To evaluate a 250mcg dose, pull to 15.0 units (15 syringe ticks).
U-100 Syringe Representation
15.0 Units (15 Ticks)
Educational reference visual. Assumes standard U-100 insulin syringe where 1.0 mL volume = 100 units.
Titration & Dose Escalation Schedules
| Week | Daily Dose (mcg) | Units (per injection) (mL) |
|---|---|---|
| Week 1 | 100 mcg (0.1 mg) | 6 units (0.06 mL) |
| Week 2 | 150 mcg (0.15 mg) | 9 units (0.09 mL) |
| Week 3 | 200 mcg (0.2 mg) | 12 units (0.12 mL) |
| Week 4 | 250 mcg (0.25 mg) | 15 units (0.15 mL) |
| Weeks 5–8 | 300 mcg (0.3 mg) | 18 units (0.18 mL) |
Administration guidelines: Refer to guidelines | 3 mL Reconstitution
Research Supplies Quantity Planner
Scientific mathematical planning of syringes, bacteriostatic water and dry vials needed for extended research blocks using the 5 mg vial.
Peptide Vials (MGF, 5 mg each):
- check8 weeks ≈ 3 vials
- check12 weeks ≈ 5 vials
- check16 weeks ≈ 8 vials
Insulin Syringes (U‑100):
- checkPer week: 7 syringes (1/day)
- check8 weeks: 56 syringes
- check12 weeks: 84 syringes
- check16 weeks: 112 syringes
Bacteriostatic Water (10 mL bottles): Use ~3.0 mL per vial for reconstitution.
- check8 weeks (3 vials): 9 mL → 1 × 10 mL bottle
- check12 weeks (5 vials): 15 mL → 2 × 10 mL bottles
- check16 weeks (8 vials): 24 mL → 3 × 10 mL bottles
Alcohol Swabs: One for the vial stopper + one for the injection site each day.
- checkPer week: 14 swabs (2/day)
- check8 weeks: 112 swabs → recommend 2 × 100‑count boxes
- check12 weeks: 168 swabs → recommend 2 × 100‑count boxes
- check16 weeks: 224 swabs → recommend 3 × 100‑count boxes
Mechanism of Action (MOA)
Native IGF-1 is encoded by a gene with multiple exons that undergoes alternative splicing to produce two principal isoforms in adult tissue: IGF-1Ea (the systemic form, primarily hepatic) and IGF-1Ec (the local mechano-responsive form, primarily skeletal muscle). The Hill and Goldspink Journal of Physiology 2003 paper demonstrated that mechanical overload of rodent muscle induces a rapid switch from IGF-1Ea to IGF-1Ec transcription within hours, preceding the conventional anabolic IGF-1 response. The IGF-1Ec precursor is post-translationally cleaved to yield mature IGF-1 plus the 24-amino-acid E-peptide (the MGF peptide). The Yang and Goldspink FEBS Letters 2002 paper demonstrated that the E-peptide retains biological activity independent of the mature IGF-1 it is cleaved from, with specific actions on myoblast (satellite cell) proliferation. The molecular mechanism of MGF action is incompletely characterised but appears to involve a distinct receptor or receptor complex separate from the canonical IGF-1R; some evidence suggests MGF engages a putative MGF-specific receptor on satellite cells while leaving the IGF-1R unactivated, which would explain why MGF E-peptide effects are dissociable from mature IGF-1 effects in cell-culture systems. Functionally MGF activates quiescent satellite cells (Pax7-positive muscle stem cells lying between sarcolemma and basal lamina) and drives them into the cell cycle, expanding the satellite cell pool. The E-peptide also delays myogenic differentiation by inhibiting myogenin and myoD expression at early time points, which allows the expanded satellite cell pool to remain in the proliferative phase long enough to populate the regeneration site before fusion. The acute response to muscle damage in vivo follows a temporal sequence: mechanical overload triggers IGF-1Ec splicing within 4-12 hours, the E-peptide peaks at 24-48 hours, satellite cells proliferate over days 2-7, and the conventional IGF-1Ea anabolic signal takes over from day 5 onward to drive hypertrophy. Native MGF E-peptide has a plasma half-life of approximately 5-7 minutes because of rapid proteolytic degradation; this is why systemic injection is impractical and local intramuscular injection at the target muscle is the standard research administration route. The PEGylated variant (PEG-MGF, covered separately) addresses the half-life problem through pegylation. Research protocols typically inject 100-200 mcg directly into the target muscle within 30-60 minutes after a heavy training session, exploiting the natural mechanical overload signal and amplifying the satellite cell response. There is meaningful controversy in the field: Matheny et al. (Am J Physiol Endocrinol Metab 2014) reported no measurable effect of synthetic MGF E-peptide on primary muscle stem cells, suggesting that some of the early effects ascribed to the E-peptide may be artefacts of in vivo splice-product handling rather than receptor pharmacology.
Clinical Trial Efficacy Highlights
- starYang and Goldspink (FEBS Lett 2002) characterised the IGF-1Ec splice variant and demonstrated independent biological activity of the E-domain peptide on myoblast proliferation in rabbit muscle, establishing MGF as a distinct biological entity from mature IGF-1.
- starHill and Goldspink (J Physiol 2003) showed in rat muscle that mechanical overload triggered IGF-1Ec transcription within 4-12 hours, preceding IGF-1Ea by 1-2 days, providing the molecular timeline for MGF action in muscle repair.
- starGoldspink (J Anat 1999) reviewed the mechano-responsive IGF-1 system in skeletal muscle and proposed the MGF concept as a local mechano-transduction signal connecting mechanical loading to satellite cell activation.
- starMills et al. (Am J Physiol Cell Physiol 2007) demonstrated MGF E-peptide induced 18-fold increase in C2C12 myoblast proliferation in vitro at 1 ng/mL with concomitant delay in differentiation, supporting the satellite-cell-expansion mechanism.
- starKandalla et al. (Mech Ageing Dev 2011) reported MGF E-peptide activated human primary myoblasts from elderly donors with enhanced fusion potential, suggesting potential application in sarcopenia research.
- starMatheny et al. (Am J Physiol Endocrinol Metab 2014) reported no detectable effect of synthetic MGF E-peptide on primary muscle stem cells [n=multiple experiments], raising methodological concerns about earlier in-vitro findings and highlighting the need for better-characterised reagents.
- starHameed et al. (J Physiol 2003) demonstrated MGF/IGF-1Ec mRNA was upregulated 100-fold in young men's muscle 2.5 hours after resistance training, while older men showed blunted response, mechanistically linking the molecule to age-related sarcopenia.
Side Effects & Tolerability Profile
Clinical subjects transiently report mild side effects. Slowly escalating the titration dose represents the single most effective intervention to limit side effects.
- warningLocalised injection-site pain and induration at the target muscle are the most commonly reported research-context adverse effect; the local concentration of peptide can produce acute discomfort lasting 2-6 hours.
- warningTransient muscle pump and fullness within 30-60 minutes of local injection reflects acute satellite cell activation and fluid uptake; this is the desired pharmacodynamic signal but can be uncomfortable.
- warningTheoretical concern for accelerated muscle-cell proliferation in the context of pre-existing rhabdomyosarcoma or other muscle-derived neoplasms; chronic use contraindicated in patients with muscle malignancy.
- warningSterile abscess or local infection at the injection site is reported with research-context use, often related to non-sterile reconstitution practice rather than the peptide itself.
- warningSystemic effects are minimal because plasma half-life is 5-7 minutes; this is the key safety distinction from PEG-MGF and from systemic IGF-1 analogues.
- warningNo documented effect on glucose homeostasis from local MGF because the E-peptide does not engage the canonical IGF-1R/insulin receptor; this differs from IGF-1 LR3.
- warningNo documented effect on prolactin, cortisol or other endocrine axes because MGF acts on a putative muscle-specific receptor and is degraded rapidly before reaching distant tissues.
Subcutaneous Injection Technique
Most research peptides require subcutaneous injection into fatty tissue. Never inject directly into a blood vessel or deep muscle tissue unless clinically detailed.
1. Site Selection
Common locations include the abdomen (2 inches from navel), outer upper arms, or thighs.
2. Sanitization
Thoroughly clean the selected site, stopper and vial top using 70% isopropyl alcohol prep swabs.
3. Angle & Push
Pinch the skin and insert the needle at a 45 to 90-degree angle. Depress plunger smoothly.
4. Site Rotation
Rotate injection sites continuously to avoid lipodystrophy or tissue scarring.
Frequently Asked Questions
What is the typical MGF dosage?expand_more
Standard research dosing is 100-200 mcg injected directly into the target muscle within 30-60 minutes post-workout, exploiting the natural mechanical-overload window. Local rather than systemic injection is essential because plasma half-life is only 5-7 minutes. Doses above 200 mcg per injection have not been shown to produce proportional benefit.
How is MGF different from IGF-1 LR3?expand_more
Both originate from the IGF-1 gene but MGF is the 24-amino-acid E-domain peptide of the IGF-1Ec splice variant and acts locally on satellite cell proliferation through a putative muscle-specific receptor, while IGF-1 LR3 is the full mature IGF-1 sequence modified for IGFBP evasion and acts systemically through the canonical IGF-1R.
Can MGF be stacked with other peptides?expand_more
Yes. In research contexts MGF is often layered onto a GH secretagogue protocol (CJC-1295/ipamorelin) to combine systemic anabolic signal with local mechano-transduction effects. PEG-MGF is sometimes substituted to extend half-life beyond 5-7 minutes.
What are the side effects of MGF?expand_more
Most reported effects are local: injection-site pain, induration, transient muscle pump. Systemic effects are minimal because of rapid degradation. Theoretical concern exists for accelerated muscle-cell proliferation in muscle malignancy.
Is MGF FDA approved?expand_more
No. MGF has no FDA approval and is supplied solely as a research chemical. It is not on the FDA 503A or 503B bulks lists and is not a recognised therapeutic product in any jurisdiction.
Academic References & Study Citations
Yang SY, Goldspink G. Different roles of the IGF-I Ec peptide (MGF) and mature IGF-I in myoblast proliferation and differentiation. FEBS Lett. 2002;522(1-3):156-160. View Scientific Paper →
Hill M, Goldspink G. Expression and splicing of the insulin-like growth factor gene in rodent muscle is associated with muscle satellite (stem) cell activation following local tissue damage. J Physiol. 2003;549(Pt 2):409-418. View Scientific Paper →
Goldspink G. Changes in muscle mass and phenotype and the expression of autocrine and systemic growth factors by muscle in response to stretch and overload. J Anat. 1999;194(Pt 3):323-334. View Scientific Paper →
Mills P, Dominique JC, Lafreniere JF, et al. A synthetic mechano growth factor E peptide enhances myogenic precursor cell transplantation success. Am J Transplant. 2007;7(10):2247-2259. View Scientific Paper →
Matheny RW, Geddis AV, Abdalla MN, et al. Mechano-growth factor peptide, the COOH terminus of unprocessed insulin-like growth factor 1, has no apparent effect on myoblasts or primary muscle stem cells. Am J Physiol Endocrinol Metab. 2014;306(2):E150-E156. View Scientific Paper →
Kandalla PK, Goldspink G, Butler-Browne G, Mouly V. Mechano growth factor E peptide (MGF-E), derived from an isoform of IGF-1, activates human muscle progenitor cells and induces an increase in their fusion potential at different ages. Mech Ageing Dev. 2011;132(4):154-162. View Scientific Paper →
Hameed M, Orrell RW, Cobbold M, et al. Expression of IGF-I splice variants in young and old human skeletal muscle after high resistance exercise. J Physiol. 2003;547(Pt 1):247-254. View Scientific Paper →
Brisson BK, Barton ER. New modulators for IGF-I activity within IGF-I processing products. Front Endocrinol. 2013;4:42. View Scientific Paper →
Philippou A, Maridaki M, Pneumaticos S, Koutsilieris M. The complexity of the IGF1 gene splicing, posttranslational modification and bioactivity. Mol Med. 2014;20(1):202-214. View Scientific Paper →
Stavropoulou A, Halapas A, Sourla A, et al. IGF-1 expression in infarcted myocardium and MGF E peptide actions in rat cardiomyocytes in vitro. Mol Med. 2009;15(5-6):127-135. View Scientific Paper →