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Growth Hormone and IGF-1 Explained!


Since I just finished up my GH and IGF e-book, and the information is still fresh in my head, I'm going to give you guys a simple explanation of what Growth Hormone and Insulin Like Growth Factor are.

First, lets go over Human growth Hormone (GH), then we'll move onto IGF-1.

GH is produced in the body by the pituitary gland. This production is as a result of Growth Hormone Releasing Hormone (GHRH) being released by the hypothalamus.

You can influence this release by nutrition and exercise. You can also inject HGH, but that doesn't make your body release it, it simply adds it into your body.

Once it is released, GH stimulates the the body's cell to both increase in size and experience more rapid cell. It enhances the rapid movement of amino acids through cell membranes. It increases the rate which amino acids are used by cells and converted into proteins like those found in muscle tissue.

IGF1 is a polypeptide hormone about the same size as insulin, released primarily in the liver (but also in peripheral tissues, like muscle- forexample) with the stimulus of Growth Hormone (GH). Mechano Growth Factor is an isoform of IGF-1 (technically it is called IGF-1Ec) released by the muscle in response to mechanical work (like lifting weights). This isoform may be responsible largely for hypertrophy induced by IGF-1.

IGF-1, in general, is probably responsible for the anabolic activity of GH. This includes both nitrogen retention and protein synthesis, as well as muscle cell hyperplasia (increase in number of muscle cells), as well as mitogenesis (the growth of new muscle fibers).

Interestingly, IGF-1 can also cause skeletal muscle hypertrophy by activating the phosphatidylinositol 3-kinase (PI3K)-Akt pathway.

This givess us reason to think that IGF-1 probably acts on most tissues to enhance growth via several possibly disparate mechanisms.

Although GH and IGF-1 are inexorably connected, they actually produce a few divergent effects.

IGF is both a known neuroprotector and neuropromotor also. Clearly, this is because there are IGF receptors within the brain and in motor neurons. Interestingly, there is no IGF receptors in fat.

Igf, therefore- must be injected intramuscularly, while GH necessarily is injected subcutaneously.

Finally, IGF is vital to the proper production of connective tissue; and both endogenous and exogenous IGF improves collagen formation and aids in the repair of cartilage. IGF is also vital to proper bone density and bone density regulation, although only GH can actually be said to be responsible for the elongation of bone tissue.

The IGF-1 available on the Black Market right now is Lr3igf-1 (Long R3 Insulin-like Growth Factor-I or Long R3IGF-I). This is simply an 83 amino acid analog of human IGF-I comprising the complete human IGF-I sequence with the substitution of an Arg for the Glu at position 3 and a 13 amino acid extension peptide at the N-terminus.


Mate thanks for some more super info.

What side effects and contra indications are there associated with GH and IGF use?


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I'm more comfortable reccomending an IM shot. You can shoot it sub-Q, but in my mind, you're risking less absorbtion if you are fat, or shoot into the fat.

IGF anecdotally doesn't work as well on fat people (leading to the rumour that you need to be under xyz% bodyfat) for it to work. I prefer IM injection, as a failsafe, when giving out general information, to avoid losing it in the fat.

Also, of note, is that IGF-1 still "burns fat" but it's more likely from a systemic effect rather than a localized lipolysis. I also prefer IM shotr of Insulin, incidentally.

You can, however, even mainline IGF-1 (think heroin addict). Hypoglycemic risk is too severe that way. I prefer my reccomendation of IM shots for IGF-1 (and steroids, insulin, etc..), and sub-Q for GH.


I was wondering the same thing as I know several folks that inject subQ. But That was a very informative post. Thanks hooker.


The IGF that we generate locally that's suspected of causing most of the muscle growth we experience is not the kind that's produced in the liver- but rather locally produced in the muscle we have worked.

The systemic response is not that great. Think about it: if it were, and this were the limiting factor, then you could do some curls, generate a systemic IGF response, and your legs, back, etc....would grow just as much as your bi's from that workout.

I think the local infusion of IGF directly into the muscle is optimal, for this and other reasons. You'll get a systemic response of sorts, by local administration into the muscle, but probably a greater systemic response (much less anabolic response) if you shoot Sub-Q.


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Just out of interest, why don't you aspirate?


Anthony, should this be taken to mean that IGF-1 may be of use in the repair of tendon injuries? If so, how should it be administered? Does it have to be injected directly into the tendon?


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Thank you Mr. Roberts. Insightfull to say the least.



No Problem.


Ok, no one talked about dosing or length of cycle. I have read 40mcg per day is effective(20mcg in the morning, 20mcg post-workout) at about 50 days on.

Also (and this is my major area of confusion) am I to assume that we are using spot injections, since there is more local anabolic activity ... and we are not really looking for an overall systemic effect?


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Thanks for the input, bush. Appreciated.
Only recently have I started researching IGF. Seems like a good use would be during PCT as a bridge to another cycle.


Is that to say that those who supplement with Glucosamine/Condroiton (assuming it works) or otherwise for joint health are getting shafted in the IGF release department? Or does the G/C help by inducing release of IGF???

Similar hypothetical, brain-storm-type question for calcium supplementation...


Good information if you plan on injecting yourself with GH or IGF-1; however, what about OTC supplements? Are these junk or do they actually work?


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I would like to hear about more IGF-1 results/experiences from people out there.

Bueller, Bueller?


Bushy, as a bridge/PCT drug how much IGF? subq? how long? :slightly_smiling: