Mechano Growth Factor (MGF)


Mechano Growth Factor (MGF) also known as IGF-1Ec is a growth factor/repair factor that is derived from exercised or damaged muscle tissue.  It's called MGF as IGF-IEa is a bit of a mouthful and harder to identify amongst the other IGF variants.

What makes MGF special is its' unique role in muscle growth.  MGF has the ability to cause wasted tissue to grow and improve by activating muscle stem cells and increasing the upregulation of protein synthesis, this unique ability can rapidly improve recovery and speed up muscle growth.  MGF can initiate muscle satellite (stem) cell activation in addition to its IGF-1 receptor domain which, in turn, increases protein synthesis turnover; therefore, if used correctly it can improve muscle mass over time.

The liver produces 2 kinds of MGF splice variants of IGF

1) IGF-1Ec: This is the first phase release igf splice variant and it appears to stimulate satellite cells into activation, This is the closest variant to synthetic MGF.

2) Liver type IGF-IEa: this is the secondary release of igf from the liver, and its far less anabolic.

mgf vs IGF-IEa

Fig 1. MGF vs. IGF-IEa

MGF differs from the second variant IGF-IEa as it has a different peptide sequence which is responsible for replenishing the satellite cells in skeletal muscle; in other words, it is more anabolic and longer acting than the systematic release of the second MGF liver variant.

So just think of MGF as a highly anabolic variant of igf.  After you have trained, the IGF-I gene is spliced towards MGF then that causes hypertrophy and repair of local muscle damage by activating the muscle stem cells as well as other important anabolic processes, including the above mentioned protein synthesis, and increased nitrogen retention.

In rats, some studies have shown muscle mass increases of 20 percent from a single MGF injection, but  somehow I think many of these studies are not accurate, however the potential is undeniable.


When you train, what happens to your muscles is they break down, the cells are damaged, muscle tissue needs to be repaired and your body produces 2 forms of MGF splice variant.  The first initial release of the above mentioned number 1 variant from the liver helps muscle cell recovery, if there is no MGF then muscle cells die.

As muscle is a post-mitotic tissue and as such cell replacement is not a means of tissue repair, if the cells are not repaired they die and your muscles get smaller and weaker.  In muscle tissue, the pool of these stem cells is apparently replenished by the action of MGF, which is produced as a pulse following damage.

Now, with synthetic injections of MGF you can increase the pulse and so speed up recovery, and increase the muscle tissue cells by stimulating satellite cells into full maturity. In terms of dosages, 200mcg bi-laterally is the very best choice of dosing in muscles trained.

The only problem with MGF, and this is the reason I don't like it, is that it has such a short half life, just a few minutes, between 5-7, and it needs to be used immediately post workout as it wont work if muscle tissue hasn’t been damaged.  That's why, for me personally, I think the best option is PEG MGF.

Nevertheless, MGF has a huge role to play, and is administered to those with muscle wasting diseases and for those who are elderly and have lost muscle mass for good reason, it is EXTREMELY anabolic.

mgf igf-1

Fig 2. MGF and IGF-1

What is PEG MGF (pegylated mechano growth factor)?

MGF that's pegylated, which means it has the addition of Polyethylene glycol - a non toxic additive that increased the half life of MGF from minutes to hours.  This means its uses and versatility make it a tremendous addition to a bodybuilders arsenal.  I have found it most effective, as its effects are systematic, that means they have a whole body effect wherever muscle has been damaged or is diseased.

How to use PEG-MGF

The next aspect we need to look at is how to make the most use of a long acting version of MGF.

When your muscle is damaged, your body releases a pulse of an MGF splice variant as I outlined above, followed by a less anabolic longer acting version from the liver.  Therefore, it seems a waste to inject MGF at this time as you will just blunt your body’s own release, your not enhancing it.  So using PEG MGF on non workout days is actually the best route.  Since the muscle has been damaged, there are plenty of receptors for MGF, and the effects are systematic.  All muscles will be aided in recovery through increased nitrogen retention, protein turnover, and satellite cell activation.  Recovery is just going to sky rocket.  Doing this means you're increasing the length of your body’s own mechanism for muscle repair and growth, and you're opening up the anabolic window.


Running PEG MGF in synergy with IGF is perfect but there are things you need to know.  Since IGF has such strong receptor affinity, if you dose them at the same time, the effectiveness of MGF will just be wasted, at least on paper (the science supports this claim).  However, further trials that I, and others, have conducted leads this to being inconclusive.

My suggestions for use are as follows

IGF DES on workout days Pre-workout, or IGF1-LR3, this wont blunt your body’s own MGF release from the liver. Whereas IGF1-LR3 has a more systematic effect and only a very small localized anabolic effect, DES on the other hand is very anabolic in a localized way.  Therefore, bring up lagging muscle parts with DES, and then the following day Dose MGF at 200-400mcg subq to increase recovery and the mechanism for growth. Perfect synergy.

My experiences

Over a 4 week run, I noticed about 4lb increase with the PEG MGF and LR3 partnership, and roughly the same weight in fat loss, very impressive.  Though, some of my clients have noted far greater increases in muscle mass.  If you're on a steroid cycle, there is no need for the addition of DES as IGF levels will already be elevated; you're better off with MGF, PEG MGF can take your recovery and gains to a new level.

MGF and IGF-1 LR3 can be used as a bridge between steroid cycles and during PCT to prevent muscle loss and speed up recovery.


Dosing 3 times a week as suggested above, and 1ml of BA water for every 2mg is optimal.  Storage in the fridge for up to 6 months.  Avoid exposure to heat or sunlight.


3 Responses to “Mechano Growth Factor (MGF)”

  1. Marc10s says:

    Hi Russian Star,

    Great article and very thorough. I read a few

  2. Marc10s says:

    Hi Russian Star,

    Great article and very thorough. I read a few of your articles regarding peptide hormones and you seem very knowledgable. I have a few questions that I hope you would be able to answer if you don’t mind. I am subject to Olympic style random in and out drug testing and was curious to know the length of time peptides stay detectable.

    Through most of my research full size MGF cannot be tested for and not to mention the half life is only 5-7 minutes so it would be out of your system within hours. However, being that MGF works best preworkout and direct into the muscle would it still be beneficial as overall recovery if injected subq? (into the abdominal region). Also, I was researching IGF1 des and also saw the half-life to be very short. However, even though the half-life is relatively short, do you know how they actually are able to tell if levels are too high or are there metabolites that stay in the system. I have seen quite a few athletes test positive for hgh recently, but have never heard of an athlete testing positive for IGF1

  3. Marc10s says:

    Lastly, are there any websites that you have used that you trust there products and would recommend? I greatly appreciate your knowledge and expertise.
    Thank you!

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