I have read an anrticle about an issue related to efficacy of IGF-1 and related analogs (DES, LR3, etc.) There are many reviews here about IGF-1 giving good gains, especially when used with GH. However, most of us are purchasing IGF-1-LR3 from peptide synthesis companies. However, chemical synthesis of IGF-1 completely lacks the correct disulfide bonds that impart the proper folding of the protein for its activity. IGF-1 and its analogs all require 3 disulfide bonds to generate the correct folded form of the protein, and this can only be accomplished in the body as naturally produced, or in E.coli as a recombinant source, just like how GH is made (recombinantly). Insulin is very similar in structure to IGF-1 and it also is completely inactive if synthesized chemically, it also has to be made recombinantly or extracted from a biologic source (people used to use bovine Insulin before recombinant sources). Recombinant means it is made in bacteria, which have enzymes to create these intramolecular disulfide bonds so the protein folds into the right configuration. All human clinical trials or current treatment of patients in the clinic is performed with recombinant IGF-1 or the LR3 isoform. The synthesized peptide version will have 0 biologic activity. There are countless references in the scientific literature to this effect. IGF-1 does work, but you have to use the recombinant form, which is 10X more expensive compared with chemically synthesized forms. What I find amusing are all the past threads claiming how great IGF-1 LR3 worked for bros, especially in combination with GH, but best I can surmise most were using the version of IGF-1 LR3 from chemical synthesis, which has 0 biologic activity, regardless of dosage.

Anyone have experience with recombinant or both versions?..