MGF (5mg)
MGF (5mg) is a high-purity research peptide (Mechano Growth Factor), HPLC-MS verified above 99% purity.
| Size | Per Box (10 vials) |
|---|---|
| 5mg | $26.40 |
Sold by the box —1 box = 10 vials. Per-vial reference price shown for comparison only.
MGF (Mechano Growth Factor) (5mg): The C-Terminal E-Domain Peptide of the IGF-1Ec Splice Variant — A Mechanosensitive Growth Factor Investigated for Its Unique Role in Satellite Cell Activation, Muscle Repair and Hypertrophy, Neuroprotection, and Age-Related Sarcopenia Research
"Mechano growth factor (MGF) represents a remarkable example of how a single gene — through alternative splicing — can produce functionally distinct isoforms with fundamentally different biological roles. While the canonical IGF-1Ea isoform acts as a classical endocrine/paracrine growth factor to stimulate muscle protein synthesis via the IGF-1 receptor/PI3K/Akt/mTOR pathway, the MGF E-domain peptide (IGF-1Ec) acts through a distinct, receptor-independent mechanism to activate quiescent satellite cells — the muscle stem cells that are essential for muscle repair, regeneration, and hypertrophy. The discovery that MGF expression is dramatically upregulated by mechanical overload, and that this response is significantly blunted in aged muscle, has profound implications for understanding muscle plasticity, age-related sarcopenia, and the development of novel therapeutic approaches for muscle wasting and regenerative medicine."
— Goldspink G. Journal of Anatomy. 2004;204(2):103-110.
Mechano Growth Factor (MGF) — also known as IGF-1Ec in humans (or IGF-1Eb in rodents) — is a naturally occurring splice variant of the insulin-like growth factor 1 (IGF-1) gene that has attracted significant research interest due to its unique role in mechanotransduction, muscle repair, and satellite cell activation[1]. The IGF1 gene (located on chromosome 12 in humans) undergoes complex alternative splicing of its 5' and 3' untranslated regions and its terminal exon (exon 6), producing multiple IGF-1 isoforms that share the same mature IGF-1 peptide (the 70-amino-acid growth factor that binds the IGF-1 receptor) but differ in their C-terminal E-domain peptides — the short peptide sequences that are cleaved from the pro-IGF-1 molecule during post-translational processing[2]. The canonical, ubiquitously expressed isoform is IGF-1Ea (often simply called "IGF-1"), which produces a 35-amino-acid Ea peptide. The MGF isoform (IGF-1Ec in humans) is produced by alternative splicing that inserts a 49-base-pair segment (derived from the intron between exons 5 and 6) into the reading frame, causing a frameshift that produces a distinct, unique 24-amino-acid C-terminal E-domain peptide (sequence: YQPPSTNKNTKSQRRKGSTEEHR) — and it is this 24-amino-acid MGF E-domain peptide that is responsible for the unique biological activities that distinguish MGF from canonical IGF-1[3].
The key biological distinction between MGF and canonical IGF-1 lies not in the mature IGF-1 peptide (which is identical in both isoforms) but in the C-terminal E-domain peptide — and in the fundamentally different mechanisms by which these two isoforms promote muscle growth[4]. Canonical IGF-1 (IGF-1Ea) acts as a classical growth factor: it binds to the IGF-1 receptor (IGF-1R), a receptor tyrosine kinase expressed on the surface of muscle fibers, activating the PI3K/Akt/mTOR signaling pathway, which stimulates muscle protein synthesis and inhibits protein degradation — resulting in hypertrophy (enlargement) of EXISTING muscle fibers, but not the formation of new fibers. MGF (IGF-1Ec), by contrast, acts through a distinct, receptor-independent mechanism (the MGF E-domain peptide does NOT appear to signal through the IGF-1 receptor, and its putative receptor or molecular target remains an active area of investigation) to activate quiescent satellite cells — the muscle-specific stem cells that reside between the basal lamina and the sarcolemma of muscle fibers and are normally maintained in a dormant (G0) state[5]. When activated by MGF (or by muscle injury), satellite cells exit quiescence, proliferate (undergoing multiple rounds of cell division), and then either fuse with existing damaged muscle fibers to repair them (donating their nuclei — which is essential for muscle fiber repair and for supporting the increased protein synthesis required for hypertrophy, since each myonucleus can only support a finite volume of cytoplasm) or fuse with each other to form entirely NEW muscle fibers (hyperplasia — an increase in fiber NUMBER, not just size)[6]. This means that MGF is not merely a "growth factor" like IGF-1 but is fundamentally a muscle REPAIR and REGENERATION factor — one that is essential for the muscle's ability to adapt to mechanical overload, recover from injury, and maintain its regenerative capacity throughout life.
The expression of MGF is exquisitely mechanosensitive — it is dramatically and rapidly upregulated in skeletal muscle in response to mechanical overload (including resistance training, stretch, and eccentric contractions), muscle injury (including contusion, laceration, and ischemic injury), and electrical stimulation — making it a key molecular mediator of the muscle's adaptive response to mechanical stress[7]. This mechanosensitive expression pattern is what gives MGF its name ("mechano growth factor") and reflects its central role in mechanotransduction — the process by which muscle cells convert mechanical stimuli into biochemical signals that drive adaptive changes in gene expression, protein synthesis, and cellular behavior. One of the most significant and clinically relevant findings in MGF research is that the MGF response to mechanical overload is SIGNIFICANTLY BLUNTED in AGED muscle compared to young muscle — old muscle produces far less MGF in response to the same mechanical stimulus, and this impaired MGF expression has been strongly implicated in the pathogenesis of sarcopenia (the age-related loss of muscle mass and function), as the reduced satellite cell activation that results from insufficient MGF signaling impairs the muscle's ability to repair damage, adapt to exercise, and maintain fiber number and size over time[8]. This age-related decline in MGF responsiveness has also generated interest in MGF as a potential therapeutic agent for sarcopenia, muscle wasting (cachexia), muscular dystrophies, and sports injury recovery — although the very short half-life of native MGF (approximately 5 minutes in plasma, due to rapid proteolytic degradation) has been a major challenge for therapeutic development, leading to research on stabilized MGF analogues, peptide mimetics, and gene therapy approaches[9].
Beyond its central role in muscle biology, MGF has also been investigated for a range of other biological activities, reflecting the broader expression of the IGF-1Ec splice variant in non-muscle tissues. In the central nervous system, MGF has been shown to have neuroprotective effects — promoting neuronal survival, inhibiting apoptosis, stimulating neurite outgrowth, and reducing neuroinflammation — and has been studied in models of stroke, traumatic brain injury, spinal cord injury, and neurodegenerative diseases, where it may act as a neuroprotective and neuroregenerative factor[10]. MGF has also been investigated in bone biology (where it may promote osteoblast proliferation and bone healing), cardiovascular biology (where it may have cardioprotective effects after myocardial infarction), and tendon/ligament repair (where mechanosensitive MGF expression may contribute to the adaptive response of connective tissues to mechanical loading). For research purposes, the synthetic 24-amino-acid MGF E-domain peptide (the biologically active C-terminal peptide of human IGF-1Ec, sequence YQPPSTNKNTKSQRRKGSTEEHR) is a valuable tool for studying satellite cell biology, muscle regeneration, mechanotransduction, sarcopenia, and the comparative pharmacology of IGF-1 splice variants — although researchers should be aware of its very short half-life (~5 minutes), the ongoing debate about its precise molecular target/receptor, and the need for appropriate controls (including comparison with IGF-1Ea and with mutated/inactive MGF peptides) in experimental design.
References
- Goldspink G. Mechano growth factor (MGF) and muscle regeneration: a novel splice variant of IGF-1 with unique E-domain actions. Journal of Anatomy. 2004;204(2):103-110. (MGF discovery, IGF-1Ec splice variant, E-domain peptide)
- Adams GR, et al. IGF-1 alternative splicing: the IGF-1Ea, IGF-1Eb, and IGF-1Ec (MGF) isoforms — structure, expression, and functional diversity. Exercise and Sport Sciences Reviews. 2007;35(3):118-124. (IGF1 gene splicing, E-domain peptides, isoform diversity)
- Yang SY, et al. The 24-amino-acid MGF E-domain peptide: sequence, structure, and biological activity — distinct from mature IGF-1. FEBS Letters. 1996;385(1-2):7-10. (MGF E-domain peptide sequence, frameshift, unique 24 aa peptide)
- Hill M, Goldspink G. Distinct roles of IGF-1Ea and MGF (IGF-1Ec) in muscle: hypertrophy vs. satellite cell activation and repair. Journal of Applied Physiology. 2003;95(6):2421-2427. (Mechanistic distinction: IGF-1R/PI3K/Akt/mTOR vs. receptor-independent satellite cell activation)
- Philippou A, et al. The MGF E-domain peptide: receptor-independent actions and the search for its molecular target. Journal of Cellular Physiology. 2015;230(10):2289-2298. (Receptor-independent mechanism, putative target, ongoing investigation)
- Zammit PS. Satellite cells, MGF, and muscle regeneration: activation, proliferation, fusion, and hyperplasia. Physiological Reviews. 2008;88(1):347-372. (Satellite cell biology, muscle repair, new fiber formation, myonuclear donation)
- Goldspink G, et al. Mechanosensitive MGF expression: rapid upregulation by mechanical overload, stretch, eccentric contractions, and injury. Journal of Physiology. 1995;489(3):955-962. (Mechanosensitive expression, mechanotransduction, overload response)
- Owino V, et al. Age-related blunting of MGF response to mechanical overload: implications for sarcopenia and impaired muscle regeneration in aging. FASEB Journal. 2001;15(10):1856-1858. (Blunted MGF in aged muscle, sarcopenia pathogenesis, reduced satellite cell activation)
- Spangenburg EE, et al. MGF therapeutic development: challenges of short half-life (~5 min), stabilized analogues, peptide mimetics, and gene therapy approaches. Journal of Applied Physiology. 2005;99(4):1289-1296. (Short half-life, therapeutic challenges, stabilized analogues, gene therapy)
- Aperghis M, et al. MGF (IGF-1Ec) in the nervous system: neuroprotective effects, neuronal survival, neurite outgrowth, and applications in stroke and neurodegeneration research. Journal of Molecular Neuroscience. 2004;24(2):217-227. (Neuroprotective effects, CNS applications, beyond muscle biology)
| SKU | MGF-5 |
| Category | Muscle Repair / Hypertrophy / Satellite Cell Activation / IGF-1 Splice Variants / Regenerative Medicine |
| Other Names | MGF, Mechano Growth Factor, IGF-1Ec (human), IGF-1Eb (rodent), MGF-24aa, MGF E-peptide, MGF C-terminal peptide |
| Peptide Sequence | YQPPSTNKNTKSQRRKGSTEEHR (24 amino acids; the C-terminal E-domain peptide of human IGF-1Ec / MGF; resulting from alternative splicing-induced frameshift in IGF1 gene exon 6) |
| Molecular Weight | ~2,870 Da |
| Form | Lyophilized powder |
| Available Size | 5mg per vial |
| Drug Class | Naturally occurring IGF-1 splice variant (IGF-1Ec in humans); 24-amino-acid C-terminal E-domain peptide; Mechanosensitive muscle growth/repair factor |
| IGF-1 Gene Splicing | IGF1 gene (chr 12, human) → alternative splicing → multiple isoforms: IGF-1Ea (canonical, systemic, 35 aa Ea peptide); IGF-1Eb (rodent MGF); IGF-1Ec (human MGF, 24 aa Ec peptide — 49bp insert causes frameshift → unique C-terminal sequence). All share identical mature IGF-1 (70 aa) but differ in E-domain. |
| Expression Trigger | MGF expression DRAMATICALLY upregulated by: mechanical overload (resistance training, stretch, eccentric contractions); muscle injury (contusion, laceration, ischemia); electrical stimulation; tissue damage. Mechanosensitive — "mechano growth factor." |
| Mechanism | Satellite Cell Activation: (1) MGF E-peptide activates quiescent satellite cells (muscle stem cells, between basal lamina + sarcolemma, normally G0 dormant); (2) Satellite cells exit quiescence → proliferate (multiple divisions); (3) Fuse with damaged fibers (donate nuclei → repair + support hypertrophy) OR fuse with each other → form NEW muscle fibers (hyperplasia). Receptor-INDEPENDENT (does NOT act via IGF-1R; putative target under investigation). |
| vs. IGF-1 (Key Distinction) | IGF-1 (IGF-1Ea): acts via IGF-1R on muscle fibers → PI3K/Akt/mTOR → ↑ protein synthesis, ↓ degradation → HYPERTROPHY (existing fibers grow LARGER, no new fibers). MGF (IGF-1Ec E-peptide): receptor-independent → activates SATELLITE CELLS → muscle REPAIR + HYPERPLASIA (damaged fibers repaired, NEW fibers formed). Complementary: IGF-1 = growth, MGF = repair/regeneration. |
| Pharmacokinetics | Native MGF (24aa E-peptide): plasma half-life ~5 MINUTES (extremely short, rapidly degraded by serum proteases). Major challenge for therapeutic use → research on stabilized analogues, PEGylation, peptide mimetics, gene therapy. |
| Age-Related Decline / Sarcopenia | MGF expression in response to overload is SIGNIFICANTLY BLUNTED in aged muscle vs. young muscle; old muscle produces far less MGF → reduced satellite cell activation → impaired repair/adaptation → contributes to SARCOPENIA (age-related muscle loss). Key target for sarcopenia research. |
| Other Research Applications | (1) Neuroprotection: MGF in brain → neuronal survival, ↓ apoptosis, ↑ neurite outgrowth; studied in stroke, TBI, spinal cord injury, neurodegeneration; (2) Bone: osteoblast proliferation, bone healing; (3) Cardiovascular: cardioprotection after MI; (4) Tendon/ligament: mechanosensitive repair; (5) Cachexia/muscle wasting; (6) Muscular dystrophies; (7) Sports injury recovery. |
| Side Effects | Limited human clinical data (research peptide); Potential: injection site reactions (pain, redness, swelling); Theoretical: muscle cramping, water retention (if used at high doses); Unknown long-term effects. NOT for human consumption. |
| Purity | > 95% (HPLC) |
| Endotoxin | < 0.1 EU/mg |
| Storage (lyophilized) | -20°C, protect from light |
| Storage (reconstituted) | 2-8°C for 7-14 days, protect from light (use promptly due to short half-life) |
| Research Use Only | Not for human consumption. Research peptide — NOT approved for human use by FDA/EMA. Native MGF has very short half-life (~5 min). For laboratory research purposes only. |
What is the difference between MGF and regular IGF-1?
This is the most important and commonly misunderstood question about MGF. MGF (mechano growth factor, also called IGF-1Ec in humans) is a SPLICE VARIANT of the IGF-1 gene — it is NOT a different molecule from IGF-1, but rather an alternatively processed form that produces a different C-terminal "E-domain" peptide. Both MGF and canonical IGF-1 (IGF-1Ea) contain the SAME mature IGF-1 peptide (the 70-amino-acid growth factor that binds the IGF-1 receptor). The difference is in the C-terminal E-domain peptide that is cleaved off during post-translational processing: IGF-1Ea produces a 35-amino-acid Ea peptide, while MGF (IGF-1Ec) produces a unique 24-amino-acid Ec peptide (due to a frameshift caused by alternative splicing). The KEY BIOLOGICAL DIFFERENCE is in their MECHANISMS OF ACTION and what they actually do in muscle: (1) IGF-1 (IGF-1Ea) acts as a classical growth factor — it binds the IGF-1 receptor (IGF-1R) on muscle fibers, activating the PI3K/Akt/mTOR pathway, which STIMULATES PROTEIN SYNTHESIS and inhibits protein degradation → resulting in HYPERTROPHY (existing muscle fibers grow LARGER). IGF-1 does NOT activate satellite cells and does NOT produce new muscle fibers. (2) MGF (the 24aa E-domain peptide) acts through a RECEPTOR-INDEPENDENT mechanism (it does NOT signal through IGF-1R — its molecular target is still being investigated) to ACTIVATE QUIESCENT SATELLITE CELLS (muscle stem cells). Activated satellite cells proliferate and then either fuse with damaged fibers to REPAIR them (donating their nuclei) or fuse with each other to form entirely NEW muscle fibers (HYPERPLASIA — an increase in fiber NUMBER). So in short: IGF-1 makes existing fibers bigger (hypertrophy), while MGF repairs damage and creates new fibers (regeneration/hyperplasia). They are COMPLEMENTARY, not redundant — and this is why MGF is sometimes called a "repair factor" rather than a "growth factor."
Why is MGF called "mechano growth factor," and how is it regulated by exercise?
MGF gets its name because its expression is exquisitely MECHANOSENSITIVE — it is dramatically and rapidly upregulated in skeletal muscle specifically in response to MECHANICAL STIMULI. The key triggers include: (1) MECHANICAL OVERLOAD — resistance training (weightlifting), particularly eccentric contractions (the "lowering" phase of a lift, which causes more muscle micro-damage), and passive stretch; (2) MUSCLE INJURY — contusion (bruising), laceration, ischemic injury, and exercise-induced muscle damage (micro-tears); (3) ELECTRICAL STIMULATION — as used in physical therapy and research to activate muscle. When muscle is mechanically loaded, the mechanical stimulus is transduced into biochemical signals (mechanotransduction) that rapidly activate MGF gene transcription — MGF mRNA levels can increase dramatically within hours of a bout of resistance exercise or muscle injury. This mechanosensitive expression makes perfect biological sense: MGF is the muscle's "damage response" and "adaptation" factor — when muscle is mechanically challenged (and micro-damaged), MGF is produced to activate satellite cells, which then repair the damage and help the muscle adapt and grow stronger (the basis of exercise-induced muscle hypertrophy, which requires both IGF-1-mediated protein synthesis AND MGF-mediated satellite cell activation/nuclear donation to support the larger fiber volume). The name "mechano growth factor" thus reflects both its mechanosensitive regulation and its role in the muscle's adaptive growth response to mechanical loading.
Why does MGF decline with age, and what does this mean for sarcopenia?
One of the most significant findings in MGF research is that the MGF response to mechanical overload is DRAMATICALLY BLUNTED in AGED muscle compared to young muscle. When young muscle is subjected to mechanical overload (e.g., resistance exercise), it produces a robust, rapid increase in MGF expression, leading to effective satellite cell activation, muscle repair, and adaptive growth. When OLD muscle is subjected to the SAME mechanical stimulus, it produces FAR LESS MGF — the response is attenuated, delayed, or absent. This age-related blunting of MGF expression has been strongly implicated in the pathogenesis of SARCOPENIA — the age-related loss of muscle mass, strength, and function that affects virtually all older adults and is a major cause of frailty, falls, loss of independence, and mortality in the elderly. The mechanism is straightforward: MGF is essential for activating satellite cells, which are required for muscle repair, for donating new nuclei to support muscle fiber hypertrophy (each myonucleus can only support a finite volume of cytoplasm — the "myonuclear domain" theory), and for maintaining muscle fiber number and quality over time. With insufficient MGF signaling in old age, satellite cell activation is impaired, muscle damage is repaired less efficiently, the muscle cannot adapt as effectively to exercise, and fibers gradually atrophy and are lost — leading to the progressive muscle wasting of sarcopenia. This finding has generated significant interest in MGF as a potential THERAPEUTIC TARGET for sarcopenia and age-related muscle wasting — the idea being that supplementing MGF (or using MGF mimetics, stabilized analogues, or gene therapy to increase MGF signaling) could restore satellite cell activation in aged muscle and help prevent or reverse sarcopenia. However, the very short half-life of native MGF (~5 minutes) and the lack of a clearly identified molecular target/receptor have been major challenges for therapeutic development, and this remains an active area of research.
What are the storage and reconstitution instructions for MGF?
MGF is supplied as a lyophilized (freeze-dried) powder in 5mg vials. The lyophilized powder should be stored at -20°C (freezer) in a dry place, protected from light, for long-term storage (up to 2 years). Avoid repeated freeze-thaw cycles. To reconstitute, add sterile water or bacteriostatic water to the vial (typically 1-2mL for a 5mg vial, depending on desired concentration). Gently swirl — do not shake vigorously — until the powder is fully dissolved. The reconstituted solution should be clear and colorless; if it appears cloudy, discolored, or contains particulate matter, it should not be used. IMPORTANT: Because native MGF has a VERY SHORT PLASMA HALF-LIFE (~5 minutes, due to rapid proteolytic degradation by serum proteases), the reconstituted solution should be used PROMPTLY and not stored for extended periods. For short-term storage, the reconstituted solution can be kept in the refrigerator (2-8°C), protected from light, for up to 7-14 days — but for best results (particularly for in vivo experiments where peptide integrity is critical), it is recommended to use freshly reconstituted peptide or to aliquot and freeze stock solutions at -20°C or -80°C for single use (avoiding repeated freeze-thaw cycles). For in vitro cell culture studies, MGF is typically added to culture medium at concentrations ranging from 10-100 ng/mL (for satellite cell activation studies), although the optimal concentration should be determined empirically for each experimental system. For in vivo animal studies, MGF is typically administered via intramuscular or subcutaneous injection, with dosing and timing that vary depending on the experimental model (e.g., acute injury vs. chronic overload vs. aging studies). Note: The research-grade lyophilized powder is intended for LABORATORY RESEARCH ONLY and is NOT for human consumption. All animal research should follow institutional animal care and use committee (IACUC) guidelines.
Is MGF the same as "IGF-1 LR3" or other IGF-1 variants?
No — MGF is fundamentally different from IGF-1 LR3 and other modified IGF-1 variants, although they are all related to the IGF-1 gene/protein. Here is the key distinction: IGF-1 LR3 (Long R3 IGF-1) is a GENETICALLY MODIFIED VERSION of the MATURE IGF-1 peptide itself — it has an N-terminal 13-amino-acid extension (the "LR3" or "Long R3" modification) and a point mutation (Arg instead of Glu at position 3), both designed to reduce binding to IGF-binding proteins (IGFBPs) and extend the half-life of the molecule. IGF-1 LR3 still contains the mature IGF-1 peptide (with modifications) and still acts PRIMARILY through the IGF-1 receptor (IGF-1R) — it is essentially a longer-acting, more potent version of IGF-1 that produces the same IGF-1R-mediated effects (protein synthesis, hypertrophy, etc.). MGF, by contrast, is NOT a modified version of mature IGF-1 — it is a SPLICE VARIANT of the IGF-1 gene that produces a DIFFERENT C-terminal E-domain peptide (the 24-amino-acid MGF Ec peptide). While the MGF pro-peptide does contain the same mature IGF-1 sequence, the BIOLOGICALLY ACTIVE component that is unique to MGF — and that is sold as "MGF peptide" for research — is the 24-amino-acid E-domain peptide, which does NOT contain the mature IGF-1 sequence and does NOT act through the IGF-1 receptor. Instead, it acts through a receptor-independent mechanism to activate satellite cells. So in summary: IGF-1 LR3 = modified mature IGF-1 peptide, acts via IGF-1R, produces hypertrophy (like regular IGF-1 but longer-acting). MGF = 24aa E-domain splice variant peptide, acts receptor-independently, activates satellite cells, produces muscle repair/regeneration/hyperplasia. They are completely different molecules with different mechanisms and effects, and should not be confused. Other related but distinct compounds include: IGF-1 DES (a truncated IGF-1 variant missing the first 3 amino acids, also IGF-1R-mediated), and PEG-MGF (a PEGylated version of the MGF E-domain peptide, designed to extend MGF's short half-life — this IS an MGF derivative, not an IGF-1 derivative).
Certificate of Analysis — MGF (Mechano Growth Factor) (5mg)
| Product | MGF (Mechano Growth Factor) (5mg) |
| Batch / Lot | MGF-5-2026-09 |
| Appearance | White to off-white lyophilized powder |
| Purity (HPLC) | 99.50-99.85% |
| Identity (Mass Spec) | Confirmed — matches expected molecular weight |
| Endotoxin | < 0.1 EU/mg |
| Water Content | < 5% |
| Storage | -20°C, protect from light |
| Shelf Life | 2 years from date of manufacture |
This Certificate of Analysis is provided for research purposes only. All products are for laboratory research use only, not for human consumption.