I think you guys are going down the wrong path on this.
The idea that there are "impurities" of some sort contaminating HGH, which trigger the same set of side effects that have been constant since pharma extracted GH from corpses, became LESS common with the advent of synthetic GH (and increasingly rare as excipient formulations were improved), then increased again with UGL production points to some other, common factor between natural. pharma, and UGL HGH.
I believe the side effects are an immune response. The primary suspect are aggregates, which have been proven to induce growth hormone antibodies. These aggregates are a characteristic of the GH of elderly patients (and probably post death degradation), pharma, and UGL HGH.
The difference is that pharma is conscious of aggregation and the immunogenicity it can induce. Among other things, excipient formulation and packaging is designed to minimize this from happening. They test for aggregation.
Does UGL? Doubtful.
Below is a study of several pharma HGH formulations published by the Journal of Pharmaceutical Science, subjected to stress to speed the formulation of aggregates (agitation, freeze/thaw, etc). The aggregates are characterized, and immune response in animals is measured.
(it's interesting to note how
wildly the different pharma formulations differ in their effectiveness at suppressing aggregation)
TLDR: The more aggregates present, the stronger the immune response, and the higher likelihood of side effects like edema.
(it's more complicated than that, as some aggregates don't induce a response, but in general, the fewer aggregates the fewer antibodies are produced.)
Like IGF blood testing is a proxy for HGH quality, it might be more productive to have users get a Growth Hormone Antibody blood test at a certain amount of time post administration. This is commonly available at the usual labs. Quest, etc. Researchers cannot intentionally inject healthy human subjects with bad HGH loaded with aggregates, but the PED community does, inadvertently.
I will add, in my own informal tests, Tesamorelin. notorious for aggregate formation and antidrug antibody formation, exhibits significantly reduced site reactions (PIP, redness) and other side effects with some of the filtration techniques used to reduce aggregates prior to injection. The difference is dramatic and the effect absolutely not psychosomatic.