PEG-MGF is a modified version of the IGF-1 metabolite, MGF, also known as mechano growth factor, found naturally in the body. However, natural MGF has a very short half-life, in the vicinity of five minutes, making it so that you are unlikely to experience significant benefits from exogenous administration.

However, PEG-MGF has polyethylene glycol (PEG) added to its structure, giving it the ability to last several days in the body before being cleared. This simple modification exponentially improves the practicality of using MGF, and makes it the best IGF-I based synthetic metabolite.

Effects of PEG-MGF

The effects of PEG-MGF are significant and noticeable. It significantly improves recuperation, can help minimize the effect of DOMS, and also elicit increased protein synthesis for muscle hyper trophy.

PEG-MGF Pharmacology

PEG-MGF, when occurring naturally as MGF, is sometimes known as IGF-IEc, made from IGF-I itself, in response to muscle tissue damage. It is in these muscle cells that MGF accelerates the uptake of amino acids and decreases the rate of protein loss, favoring a positive nitrogen balance.

However, this is just a small part of its mechanism. A significant aspect of its magnitude of effects are related to its ability to stimulate satellite cells adjacent to the site of muscle damage. Satellite cells can be considered immature stem cells which are capable of creating new muscle cells if directed to do so. By activating these cells in an area adjacent to the actual muscle damage, PEG-MGF is able to reduce significant muscle hyper trophy in a location exceeding the site of damage.

This is an important mechanism for stimulating new muscle growth, especially in older individuals who experience diminished satellite cell recruitment and may be subject to sarcopenic muscle loss.

PEG-MGF Dosage

The modification made to MGF gives it an advantageous dosing profile, with the ability to be dosed infrequently. Even though the exact frequency of administration is not set in stone, it may be administered post workout, on rest days or a combination of both.

Most athletes that use it for hyper trophy and recovery properties tend to do so almost once daily, via the subcutaneous route. A dose of between 200 to 500 µg on off days and 100 to 200 µg at the post workout interval are the most common dosages used. Cycle lengths are also typically limited to a maximum of four weeks owing to the fact that desensitization occurs rapidly.

Possible Adverse Effects Of PEG-MGF

Official statistics of reported side effects from PEG-MGF are limited, owing to the fact that it has not been studied extensively in clinical settings. However, based on anecdotal reports of users, the most common manifestations of adverse effects include localized pain and inflammation at the site of injection. This is almost often the result of incorrect injection technique or poor reconstitution of the powder.


While PEG-MGF is an exciting peptide for supporting recovery and hyper trophy, it is not as potent as exogenous IGF-I. However, what many experienced athletes do is bridge a PEG-MGF cycle with IGF-I, allowing for longer cycle lengths and cumulative effect. They should, however, not be administered simultaneously as they both compete for the same receptor.