Manufacturing of these peptides is just as gray for the Chinese as it is for us. I suspect there are a very small number of clandestine chemists out there making these -- but a much larger number of sales agents creating their own companies to buy the peptides in bulk with the hopes of selling them "over the wall" to the West.
Many peptides are widely tolerated because they are not toxic and largely do not trigger allergic reactions. Some don't do anything at all, to speak of.
If there truly is a batch of reta out there that is actually-not-reta-and-instead-some-sort-of-toxic-material, there will be more sick people due to the distribution webs, and there will be a wider variety of symptoms rather than the ones that look suspiciously like a reta overdose.
(If I'm wrong here, I'll gladly admit it and apologize.)
Glad this was brought up for discussion, but I remain skeptical.