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Thread: Insulin Like Growth Factor~IGF 1
10-23-2010, 02:15 PM #16
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- Jul 2010
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10-25-2010, 10:40 PM #17
10-27-2010, 12:35 PM #18
My basic take on it is that igf1-lr3 is a decent, fast-acting insulin similar to humalog. The benefit I can see in using it is that some report good gains from it with less of a risk of going hypoglycemic. The idea being that it may be more effective at slightly lower doses and offer a slight (and I do mean slight if this is the case) benefit vs risk advantage over most fast-acting insulins. Other than that, it's basically not going to work like a typical igf-1 because the chemical structure isn't even close to what our bodies want for hyperplasia etc. It was modified in the lab to last longer in petri dishes. It's an 83 amino acid chain vs. the 70 amino chain bio-identical igf-1 is. So, not a good option for hyperplasia/site-enhancement, but decent as an insulin for pre-workout use. Humalog and humulin-r are much cheaper and do the same thing though.
MGF is potentially effective for site-enhancement. In its unmodified form (non pegylated) it is bioidentical. In other words, it's recognized by our system as a usable form. It is good at "activating" satellite cells when used immediately post workout. Special precautions should be taken in handling it and prepping it for use- i.e. freeze what you aren't going to use within 2 weeks in single dose slin pins and thaw them out as needed (i.e. right before your workout).
Regular igf-1 is hard to find and quite expensive by comparison. But, the good news is that some peptide suppliers are starting to carry des (1-3) igf-1. It, like original igf-1, is bio-identical. It is produced in the body after exercise when lactic acid removes the last 3 amino acids from the chain of regular igf-1. This makes it resistant to binding proteins meaning more will be used by the muscles/receptors. On paper, though it has a short half-life, it is 10 times as potent as original igf-1 (for reasons mentioned above). Like igf-1 (non lr3) it is good for "defining" or "differentiating" satellite cells and helping them become new muscle. This is an over-simplification but basically mgf is good at telling the embryonic cells to "wake up" and des igf-1 is good at telling them to "grow up"! It should be used 1/2 hr after your mgf shot and dosing is still a bit of a mystery. I plan on using 40 mcg divided bilaterally as soon as I get my hands on some. (yep, I'm spouting off about something I haven't tried :P Though I've tried all the commonly available forms out now.)
10-27-2010, 12:40 PM #19
I should have noted that peg-mgf is also "bio-identical" as the structure of the actual amino acid sequence has not been altered. But, pegylation can sometimes render the molecules too "heavy" to enter the receptors. Plus, prolonging the half-life means that most of the product is going systemic instead of being used quickly by the muscles it is injected into. This isn't what we're after with this product. I will be sticking with regular mgf myself.
12-28-2010, 02:24 PM #20
Any opinions on the effectiveness of IGF as a standalone to build muscle?
12-29-2010, 08:05 AM #21
06-11-2013, 02:50 PM #22
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- Feb 2009
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Exp Physiol. 2013 May;98(5):1038-52. doi: 10.1113/expphysiol.2012.070722. Epub 2013 Jan 4.
Overexpression of insulin-like growth factor-1 attenuates skeletal muscle damage and accelerates muscle regeneration and functional recovery after disuse.
Ye F, Mathur S, Liu M, Borst SE, Walter GA, Sweeney HL, Vandenborne K.
Department of Physical Therapy, PO Box 100154, Room 1142, PHHP Building, University of Florida, Gainesville, FL 32610, USA.
Skeletal muscle is a highly dynamic tissue that responds to endogenous and external stimuli, including alterations in mechanical loading and growth factors. In particular, the antigravity soleus muscle experiences significant muscle atrophy during disuse and extensive muscle damage upon reloading. Given that insulin-like growth factor-1 (IGF-1) has been implicated as a central regulator of muscle repair and modulation of muscle size, we examined the effect of virally mediated overexpression of IGF-1 on the soleus muscle following hindlimb cast immobilization and upon reloading. Recombinant IGF-1 cDNA virus was injected into one of the posterior hindlimbs of the mice, while the contralateral limb was injected with saline (control). At 20 weeks of age, both hindlimbs were immobilized for 2 weeks to induce muscle atrophy in the soleus and ankle plantarflexor muscle group. Subsequently, the mice were allowed to reambulate, and muscle damage and recovery were monitored over a period of 2-21 days. The primary finding of this study was that IGF-1 overexpression attenuated reloading-induced muscle damage in the soleus muscle, and accelerated muscle regeneration and force recovery. Muscle T2 assessed by magnetic resonance imaging, a non-specific marker of muscle damage, was significantly lower in IGF-1-injected compared with contralateral soleus muscles at 2 and 5 days reambulation (P<0.05). The reduced prevalence of muscle damage in IGF-1-injected soleus muscles was confirmed on histology, with a lower fractional area of abnormal muscle tissue in IGF-1-injected muscles at 2 days reambulation (33.2?3.3 versus 54.1?3.6%, P<0.05). Evidence of the effect of IGF-1 on muscle regeneration included timely increases in the number of central nuclei (21% at 5 days reambulation), paired-box transcription factor 7 (36% at 5 days), embryonic myosin (37% at 10 days) and elevated MyoD mRNA (7-fold at 2 days) in IGF-1-injected limbs (P<0.05). These findings demonstrate a potential role of IGF-1 in protecting unloaded skeletal muscles from damage and accelerating muscle repair and regeneration.
PMID: 23291913 [PubMed - in process]
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07-24-2013, 09:30 PM #23