Here is an article I really liked:
by Gavin Kane
Mechano Growth Factor is the hottest buzz word in the bodybuilding community right now, as much as or more so than IGF of the late 90’s and then again with the LR3 variant in the early 2000’s. So what is Mechano Growth Factor or MGF as it is commonly called? If you do a quick search on some of the many bodybuilding web boards you will see a host of information, some of it correct, most of it wrong.
Unfortunately, with the ease of search functions, it is all too easy for anyone to claim to be a guru (I hate that word) now a days, and write what appears to be a definitive article on MGF or anything else they fancy. The fact is that this product is still in clinical trials and real world information is severely limited. This article will attempt to shed some light on the current hype, use, and science behind this new wonder drug.
Let’s start with an explanation of MGF and what it does. MGF is part of the muscle insulin-like growth factor-I (IGF-I) mRNA splice variant IGF-IEc and was first isolated and identified in rodents. IGF-IEc, is more commonly called Mechano Growth Factor and has been found to be up-regulated by exercise or muscle damage. Growth hormone (GH) is the principal regulator of IGF-I expression in several tissues including the skeletal muscle.
MGF is derived from IGF-I but its sequence differs from the systemic IGF-I produced by the liver. MGF is expressed by mechanically overloaded muscle and is involved in tissue repair and adaptation. It is expressed as a pulse following muscle damage and is apparently involved in the activation of muscle satellite (stem) cells. These donate nuclei to the muscle fibers that are required for repair and for the hypertrophy processes which may have similar regulatory mechanisms (Goldspink, G., 2005, p. 22).
IGF-I exists in multiple isoforms (tissue-specific proteins of functional and structural similarity). One isoform, which differs from the systemic or liver type, happens to be particularly sensitive to mechanical signals such as the gamut of exercise overload. MGF is the local splice variant of IGF-I produced by damaged or loaded skeletal muscle (Dluzniewska J, et al.., 2005 p. 258).
The physiological function of MGF was studied using an in vitro cell model. Unlike mature IGF-I, the distinct E domain of MGF inhibits terminal differentiation while increasing myoblast proliferation. Blocking the IGF-I receptor with a specific antibody indicated that the function of MGF E domain was mediated via a different receptor. What this means to you is that MGF will most certainly grow new cells. known as hyperplasia, the holy grail of muscle building. This has been speculated over for years in growth hormone research and now there is finally evidence through lab tests, of the mechanical function of hyperplasia. (Yang SY, Goldspink G., 2002, p. 156-60).
Alright, by now you are probably brain fried so I will switch gears and get to the good stuff. In really simple terms, MGF is a variant of IGF-1, an isoform that is particularly sensitive to muscle trauma (weight training) and is essential for repair and growth of new cells, similar in manner to IGF-1. What you need to know is MGF triggers new cell growth or hyperplasia in rat testing, and since we as bodybuilders fancy ourselves as lab rats, it is currently the in vogue peptide by top amateurs and pro’s.
Well all of this sounds great but what is the catch? This is where we reach a cross-road, a potential problem with MGF. As great as MGF has been in clinical trials and rat studies, the fact is that injected MGF has a half life of minutes….yes minutes. So how are you going to make this work, besides injecting every hour or so of your waking day? The answer lies in a little known molecule protection agent known as PEGylation.
So what is or PEGylation? In simple terms it is the process of attaching one or more chains of a substance called polyethylene glycol (PEG) to a protein molecule such as IGF or in this case MGF. Since the body does not react to PEG, it helps provide a protective barrier around an attached protein so it can survive in the body longer. This is highly beneficial for systemic products that must survive repeated attacks by enzymatic exposure. PEG is an inert non-toxic substance that can provide protection to amine groups since they are flexible and allow attachment by bioengineered processes to the receptor bearing cell. Finally a quick explanation of polyethylene glycol; Any of a family of high molecular weight compounds that can be liquid or wax-like in consistency and are soluble in water and in many organic solvents.
Polyethylene glycol itself does not react in the body and is very safe. PEG has been approved by the US Food and Drug Administration (FDA) as a base or vehicle for use in foods and cosmetics and in injectable, topical, rectal and nasal pharmaceutical formulations. The risk associated with current PEGylated drugs are due to the way the drug itself acts not the PEG. There is current research testing PEGylation of growth hormone, which will allow the amino structure to have a longer half life in the body, leading to more sustained blood levels. The science of PEGylation is very valid and I predict will become far more prominent in peptide chains in the near future.
PEGylation can improve dosing convenience of many small molecules by increasing bioavailability and reducing dosing frequency. PEGylation also increases the amount of time the cell sits at the target site. This can be both good and bad. It is good because it increases the drug concentration, and with a longer time at the site, there is more chance of uptake by the cell. The bad news is that while it is sitting at the cell, there is increased risk of damage by enzymes that attack the cell. This is a double-edge sword that is a necessary evil; you must protect the molecule but at the same time increase the risk factor of damage due to longer exposure times at the target cell. As a result of the increased time at the cell, the optimal drug concentration can be achieved with less frequent dosing; a significant benefit to bodybuilders who are usually using poly-pharmacy at its finest.
PEGylated MGF is systemic in nature, meaning that the method of administration is not important. Most people are using MGF in a fashion similar to IGF, injecting the peptide intramuscularly in recently trained muscle groups, hoping for an increase in cell repair and proliferation of new cells. While this thinking is optimistic at best, there is no research that would support site specific injections being beneficial for localized growth. This is a myth that has purveyed aas and peptide use for years. At this time, the literature and lab studies support subcutaneous injection, using small gauge insulin syringes.
The peptide is still in research phases and use by athletes at this time is all by trial and error. One company that currently carries MGF has conducted their own research trials, using test participants from underground steroid boards who provided feedback in weekly intervals. While this is hardly a controlled environment and may have too many variables to accurately assess the product, at least it is a start.
For dosing information, as with most peptides, more is not better. Smaller doses with less frequent injection schedules have proven to be optimal. Dosage reports so far have been using 200mcg injected sub-q, two or three times per week. Because PEGylated MGF has a half life of up to 42 hours, it is advised to space injections to every other day use, or three times per week with at least one day in between. Time of day is also important for injections, especially if you are using IGF-1, rhGH, and other peptides in addition to MGF. You must space the injection time of MGF as far as possible from IGF-1 and rhGH since the peptide structures are somewhat competing.
Elite athletes are experiencing incredible body fat loss, increased pumps, fullness, and vascularity. Users are claiming up to 5-6 pounds of lean mass and body fat loss of 2-3% in 4 weeks of use. Some report continued use for weeks 5 and 6 but with no further gains or body fat loss. It seems that MGF stalls out at the 4 week mark, my theory being that much like with media grade IGF-1 LR3, the cells reach super saturation and cannot process any further uptake of the peptide sequence. It is possible to bypass this saturation, but it will take some time to work out the differential nature of the timing, much like I had to do with IGF-1 LR3, where I have now found ways to take it for up to 20 weeks with little to no cell down-regulation.
At this time all use and injection schedules are by word of mouth, sometimes by erroneous information on underground boards. Proper use of MGF is merely by speculation; it will take some time to sort out the best method of administration, although with the ever changing world of science, where nothing ever stands still, it may take years to sort out optimal dosing schedules. Even with such stable peptide structures as growth hormone that have had years of research, new information is always being studied, and I speculate that it will with all peptides.
