well since your qouting the 4 week on 4 week off info, then i can say for certain your reading a lot of the old information and articles on igf-1 lr3 that came out 14 years ago when that was what everyone said, and they said your receptors would shut down after 4 weeks, so u had to stop, which turned out to be BS short for bullshit. Next yes it use to be very expensive, i use to sell 1mg for $325 , yep, the cost dropped that much over the years!
next you have media grade and receptor grade, everyone takes media grade, and most of the Manufacturer prices that are still super high on igf are for receptor grade, and anyone who says they sell receptor grade is a liar plain and simple, but their is no real difference for our bodybuilding purposes, as you get the same exact effects and due to it being cheaper, you actually get more out of media grade than receptor grade when it comes down to how much your able to use due to cost.
To put it simply, the use and expense of Receptor Grade IGF is wasted on most research, especially the kind that is likely to be done by members here. RG is for very specific methodologies of research requiring EXACTING tolerances to reduce variables in the experimentation process - specifically, mostly in the area of immunohistochemistry. (We're talking on the microscopic level within serum-free or reduced-serum culture media).
Media Grade IGF is a lesser expensive form of the exact same product with the same purity standard. MG is also for precise experimentation but designed as a more affordable alternative for use in experiments not demanding the exacting tolerances necessitating RG. (1)
Here is the info directly from the manufacturer's (and patent holder's) website:
Human LONG™R³IGF-I (Media Grade)
Purity: > 85 % (by N-terminal sequence analysis)
Molecular Weight: 9110 +/- 2 daltons – confirmed by Mass Spectrometry
N-terminal sequence analysis: 18 residues > 95 % single sequence
Biological Activity: Type 1 IGF receptor binding assay: ED50 > 15 ng/ml
IGF binding protein assay: ED50 > 200 ng/ml
Stimulation of protein synthesis in rat L6 myoblasts: ED50 < 10 ng/ml
Endotoxin: < 0.1 EU/µg
Human LONG™R³IGF-I (Receptor Grade)
Purity: >95 % (by HPLC and N-terminal sequence analysis)
Molecular Weight: 9111 daltons – confirmed by Mass Spectrometry
N-terminal sequence analysis: 18 residues > 95 % single sequence
Biological Activity: Type 1 IGF receptor binding assay: ED50 > 15 ng/ml
IGF binding protein assay: ED50 >200 ng/ml
Stimulation of protein synthesis in rat L6 myoblasts: ED50 < 10 ng/ml
Endotoxin: < 0.1 EU/µg
So above you can see the purity is slightly different (3), and the only other marked difference (if you can even consider it “marked”) is the molecular weight. The media grade may be off a dalton or two from the receptor grade.
Allow me to put this into a little plainer form of English. You can drive a Ferrari or a High Performance BMW M series. Both are hand-built. Both go real fast. You will get plenty of ass driving either one. But you can’t open up either one on the freeway because you’re hampered by traffic, speed limits, etc…
What’s the diff. then? You’ll pay about a hundred grand for the BMW, and about five times that for the Ferrari. Why!?!
I’ve seen many posts on IGF and many of them say many different things. Many of them say the same thing. Doesn’t mean any of them are right.
I saw a post by someone who is a rather respected Vet on the boards who stated “Only buy Lyophilized powder form of IGF! This is the only way it comes and any other form is faked, or junk, or ruined”. (2) Not true. Yes, Lyophilized powder is more stable than an improperly reconstituted form, but there are other factors that will play into that purchase. Perhaps the most import reason you don’t want to buy Lyo IGF is the fact that the IGF peptide is EXTREMELY delicate. It’s best to operate in a nitrogen environment, and when possible (and necessary) at slight vacuum (-25 kPa to be more specific).
Filtering requires some special skill and equipment also. (Taken from manufacturer’s site: Filter Sterilization of GroPep Peptides If sterilization is required, the peptide solution should be filter sterilized using a membrane with low protein binding; an example of this is the Millipore Millex-GV Cat. No. SLGV025LS.
Note that extreme care must be exercised in filtering dilute protein solutions because of the likelihood of adsorption to the filter. Growth factors require the same care in handling. Filtration for sterility is best done on either the 1 mg/ml stock solution or the 0.1 mg/ml working solution diluted in 10 mM HCl. It may be possible to filter more dilute solutions if a carrier protein is present but caution should be exercised.
Important Recommendations:
*Do not add the peptide to low protein or protein free media prior to filter sterilization.
*Use a filter membrane with low protein binding characteristics.
*Filter sterilize the IGF peptide separately at a concentration of 0.1 mg/ml (diluted in 10mM HCl) or greater.)
Chances that you’re going to fuck it up… ? Pretty damn good. This is why you want to buy your IGF properly reconstituted and in the proper medium with the right pH (done with Glacial Acid, Acetic Acid ,HCL acid (10 mM HCl), not vinegar or many of the other “methods” I’ve seen lately).
I’ve also seen many posts from equally respected Vets touting the advantages of RG over MG and why the only IGF with which to go is RG. They are equally mistaken and equally unqualified to render this opinion. It’s not true. Plain and simple.
(1) From the manufacturer's website: GroPep scientists have produced Media Grade human LONG™R³IGF-I to provide an inexpensive yet high quality potent IGF-I analog for use as a growth factor supplement for serum-free or reduced-serum culture media. GroPep scientists have engineered this analog with the express purpose of increasing the biological activity of the IGF-I molecule. LONG™R³IGF-I is significantly more potent than human IGF-I in vitro. The enhanced potency is due to decreased binding of LONG™R³IGF-I to IGF binding proteins which normally inhibit the biological actions of IGFs.
(2) I contacted Gropep and most of the media grade actually far surpasses that standard and is not much different that RG, only that they cannot guarantee the purity standard exceeds that of the RG, and thus, sell it as MG. The letter from Gropep also was sure to state at the very end "Be aware that NO GroPep product is approved for use in humans."
(3) Lastly i will say this, this is the 2nd time you said you think its fake, so if 14 years of customer reviews arent enough, then go someplace else!
(4) Now couple the fact that the only big difference is price between RG & MG, and youll see that you will get much more out of being able to use much higher dosages and buy much more media grade at its cost and will get a whole lot more from MG than you ever would RG.
(5) I have used both RG and MG IGF-1 lr3 and can tell you with 100% certainty, their is not a lick of difference! Also if you search back about 12 years or so in this forum, youll also find many others who compared usuing RG and MG igf-1 lr3 and all not some but ALL of them said their was no notable difference other than Price
(6) Yes some peptide companies say theyre selling Receptor Grade IGF-1 lr3, and You can also do a search in this forum and find many people who have used other companies igf first then used ours, always say they cant believe how much better ours is, and ours is NOT any better, lol, its simply real! You either can get your hands on real igf or you cant, we do NOT sell the chinese garbage with little 1mg lyophilized wafers they call igf-1 lr3 lol,
(7) Some of us have been around over 16 years and have had relationships with these manufacturing distributors long before most of these other peptide companies were even an idea in someones head, hell probably before some of the peptide company owners out there even hit puberty lol
