we've been getting alot of queries regarding this topic so
www.getIGF.com contacted GROPEP and recieved some information which you will find worthy of reading.
straight 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.
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 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.
there was a thread on
www.getIGF.com by a respected Vet on several boards who stated “Only buy Lyophilized powder form of IGF-1!" This is the only way it comes and any other form is faked, or junk, or ruined”. 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-1 at
www.getIGF.com. it comes properly reconstituted and in the proper medium with the right pH (done with HCL acid (10 mM HCl), not vinegar or many of the other “methods” at home methods.
we've also seen many posts from equally respected Vets touting the advantages of Receptor grade over Media grade and why the only IGF-1 with which to go is Receptor grade. They are equally mistaken and equally unqualified to render this opinion as the person referred to above. 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) Just as a point of clarification: we see posts about how IGF-1 not working for someone so they think they were scammed. Chances are, a large percentage of these posts are a result of damaged IGF and not necessarily a scam. Although a small amount of these people may have been scammed, IGF-1 is extremely delicate. Improper reconstitution, storage, shipping methods, excessive vibration, buying it 2nd, 3rd, 4th -hand, etc... can all cause the IGF peptide to erode. This is why it is critical that you know the source of the IGF and how it was reconstituted. At
www.getIGF.com you dont have those concerns! Our IGF-1 is properly handled and more carefully reconstituted.
(3) we contacted Gropep and the explaination they gave goes like this: The purity of the MG is actually supposed to read >85% [so editted above]; however, 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 receptor grade , and thus, sell it as media grade. 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."
=======================================================
in addition, ive spoken with a sales rep at GROPEP and this phone converstaion was summarized as such:
receptor grade IGF-1 is extremely sensitive to temperature conditions and mishandling. it can literally be destroyed in a matter of minutes in heat and/or when violently shaken or mishandled.
Receptor grade is just much more pure than media grade so lower doses work.. .20mcg-40mcg a day. but you pay for that! HEAVILY! Most texts we've examined state that for bodybuilding media grade is more than you would ever need.
The bottom line..
i doubt youll find any receptor grade IGF-1 in the u.s until GROPEP has it in their interest to spend millions of dollars on proper transportation of IGF-1 from australia to the u.s... not happening soon i can assure you of that.
at
www.getIGF.com you are guaranteed the highest quality IGF-1 period! I cannot stress enough how much effort is put to insure the IGF-1 is properly handled, transported, reconstituted, and shipped to you.. the customer!
we appreciate the time you took to read this post and hope you found it informative.
sincerely,
admin.
Please Scroll Down to See Forums Below 
