Yes.
HGH is the only peptide / protein drug routinely monitored for immunogenicity at the clinic level. There's a blood test available for it.
One of the ways it's dealt with is switching brands, to see if antibody levels go down and the HGH starts working again. Since all HGH is somatropin, the only difference between brands are the excipient ingredients in the formulation, which mainly serve to minimize aggregation to prevent immunogenicity.
Here are children who lost response to HGH from immunogenicity and the methods used to try and fix it. "Inhibition" is how much HGH effectiveness was reduced.
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Here's a measure of the antibodies produced by different pharma formulations, most of which can be attributed to aggregates.
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UGL is certainly worse. No anti-aggregate measures are taken (slightly wrong PH alone can cause aggregation to get 10x worse). No immunogenicity tests are conducted. "I've never noticed immunogenicity". Would you notice a 15-20% drop in effectiveness over a year?
Filtering reduces immunogenicity, ensures sterility, prevents particulates like common glass delamination and stopper rubber from getting into your body and eventually your organs where they accumulate, causing micro embolisms. It's all upside.