Hexarelin vs MGF (Mechano Growth Factor)
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: Examorelin, HEX
Hexarelin is a synthetic six-amino-acid peptide (a growth hormone-releasing peptide, or GHRP) that pushes the pituitary to release growth hormone. What makes it more interesting than its cousins is a second job: it binds a receptor in heart tissue and appears to protect the heart, an effect that does not depend on growth hormone at all. It is a research compound, not an approved drug, and almost all of the heart data is from animals.
Also: Mechano Growth Factor, IGF-1Ec
MGF is the name given to a splice variant of the IGF-1 gene (IGF-1Ec in humans, IGF-1Eb in rodents) that muscle switches on after loading or damage. The "MGF" sold as a peptide is usually a synthetic 24-amino-acid copy of that variant's unique tail end (the E-domain, sequence YQPPSTNKNTKSQRRKGSTFEEHK), often with a modified C-terminus. It got famous through early lab work from Geoffrey Goldspink's group suggesting it kicks muscle stem cells into action. The honest picture is messier: a careful 2014 pharma replication found no effect on muscle cells at all, nobody has shown the free peptide actually exists in the body, and there are zero human trials.
Key Comparison Insights
- Both peptides belong to the Growth Hormone category, suggesting similar primary applications.
- Hexarelin has stronger research evidence (Human Trials) compared to MGF (Mechano Growth Factor) (Preclinical).
Detailed Comparison
| Attribute | Hexarelin | MGF (Mechano Growth Factor) |
|---|---|---|
| Category | Growth Hormone | Growth Hormone |
| FDA Status | Not FDA Approved | Not FDA Approved |
| Clinical Status | Pre I II III IV FDA | Pre I II III IV FDA |
| Mechanism of Action | Hexarelin acts through two different receptors, which is the key to understanding it. The first is the growth hormone secretagogue receptor (GHS-R1a), the ghrelin receptor in the pituitary, which is how it triggers growth hormone release. The second is CD36, a scavenger receptor found on heart muscle cells and small blood vessels, and this is where its cardioprotective story lives. Activating CD36 in the heart has been shown to improve coronary flow and protect heart tissue from ischemia (low oxygen) and reperfusion injury, and crucially these effects still happen in growth-hormone-deficient animals, proving the heart benefit is separate from the GH benefit. | The idea goes like this. When muscle is stretched or injured, the IGF-1 gene is spliced differently, producing a version with a different C-terminal E-domain. Researchers proposed that this E-domain gets cut off and acts on its own, pushing satellite cells (muscle stem cells) to multiply before mature IGF-1 tells them to fuse and build new fibers. Several studies reported that the E-peptide works without the classic IGF-1 receptor, and in heart cells it was reported to enter the cell, travel to the nucleus, and block the mitochondrial apoptosis pathway. The problem is that nobody has identified MGF's receptor, a 2010 Endocrinology review pointed out that no matching peptide has ever been isolated from cells, tissue or blood, and a 2014 study from Novartis and another drug company could not reproduce the core muscle-cell effects. So the mechanism is a hypothesis built on synthetic-peptide experiments, not established biology. |
| Common Dosing | 100-200 mcg 2-3x daily 2-3x daily | No established human dose Not established |
| Administration | Subcutaneous injection | Local injection or infusion into tissue in animal studies; research-market products are injected |
| Typical Duration | 4-8 weeks (desensitization occurs) | Single treatments or days to weeks in animal models; no human protocols exist |
| Best Time to Take | Morning and before bed (fasted) | Not established |
Possible Side Effects May vary by individual |
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| Research Summary | The growth hormone-releasing effect of hexarelin is well established in humans from older endocrine research, but the exciting cardiovascular claims are still mostly preclinical. The landmark mechanistic work (Circulation Research, 2002) identified CD36 as the receptor through which growth hormone-releasing peptides act on the heart, and follow-up rodent studies showed hexarelin improves left ventricular function and protects cardiomyocytes from ischemia-reperfusion injury, in one case through interleukin-1 signaling (2017). A 2014 review in the Annals of the New York Academy of Sciences and a 2017 PMC review both lay out a plausible cardioprotective case. But here is the honest part: there are no large modern human trials showing hexarelin treats or prevents heart disease in people, and a known limitation is rapid tolerance, the GH response fades with continued use. So the cardiac angle is genuinely interesting biology, not an established therapy. | The supportive work is real but almost all in cells and animals. Yang and Goldspink (FEBS Letters, 2002) reported that the E-domain increased myoblast proliferation and delayed differentiation. Kandalla and colleagues (2011) reported it extended the proliferative lifespan of human muscle precursor cells from young donors, but not from old donors. In sheep with induced heart attacks, local MGF E-domain preserved cardiac function and cut compromised heart muscle by about 35% (Carpenter, 2008), and similar heart-protection results came from mouse studies. A gerbil stroke model showed strong neuroprotection (Dluzniewska, 2005). Then the counterpoint: Fornaro and colleagues (Am J Physiol Endocrinol Metab, 2014) tested MGF up to 500 ng/ml on mouse and human muscle cells and primary muscle stem cells and saw no effect on proliferation or differentiation, while real IGF-1 worked fine. An accompanying editorial was titled "The Fall of Mechanogrowth Factor?". In humans, the only solid data is about gene expression: heavy leg extensions raised MGF mRNA in young men but not in older men (Hameed, 2003). There are no human dosing studies and no clinical trials. One more flag: MGF E-peptide drove growth of prostate cancer cells in a lab study, and MGF was found overexpressed in prostate cancer tissue (Armakolas, 2010). |
Frequently Asked Questions: Hexarelin vs MGF (Mechano Growth Factor)
What is the difference between Hexarelin and MGF (Mechano Growth Factor)?
Hexarelin is a growth hormone peptide that hexarelin is a synthetic six-amino-acid peptide (a growth hormone-releasing peptide, or ghrp) that pushes the pituitary to release growth hormone. what makes it more interesting than its cousins is a second job: it binds a receptor in heart tissue and appears to protect the heart, an effect that does not depend on growth hormone at all. it is a research compound, not an approved drug, and almost all of the heart data is from animals. MGF (Mechano Growth Factor) is a growth hormone peptide that mgf is the name given to a splice variant of the igf-1 gene (igf-1ec in humans, igf-1eb in rodents) that muscle switches on after loading or damage. the "mgf" sold as a peptide is usually a synthetic 24-amino-acid copy of that variant's unique tail end (the e-domain, sequence yqppstnkntksqrrkgstfeehk), often with a modified c-terminus. it got famous through early lab work from geoffrey goldspink's group suggesting it kicks muscle stem cells into action. the honest picture is messier: a careful 2014 pharma replication found no effect on muscle cells at all, nobody has shown the free peptide actually exists in the body, and there are zero human trials. The main differences lie in their mechanisms of action and clinical applications.
Which is better, Hexarelin or MGF (Mechano Growth Factor)?
Neither is universally "better" - the choice depends on your specific goals. Hexarelin is typically used for growth hormone purposes, while MGF (Mechano Growth Factor) is used for growth hormone. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can Hexarelin and MGF (Mechano Growth Factor) be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using Hexarelin and MGF (Mechano Growth Factor) together should only be considered under medical supervision, as both compounds have their own side effect profiles and potential interactions. Research on their combined use may be limited.