two separate questions running in this vial and they need different answers. sterility: two punctures with sterile technique + BAC water with benzyl alcohol doing its job = contamination risk is pretty low. fwiw “still looks clear” is a sterility observation and it’s a fine one. potency: completely separate mechanism, and clarity tells you nothing here. sermorelin (GRF 1-29) degrades via peptide bond hydrolysis. refrigeration slows that curve, it doesn’t stop it. the BUD your compounder assigned wasn’t arbitrary - it’s when they can no longer vouch for the peptide being above threshold (usually 90%+ of label claim). compounded 8/12/25, BUD 11/10/25 = they gave it a ~90 day window. you’re looking at this in may 2026, so you’re about 6 months past BUD on something that was already flagged with a relatively tight window because sermorelin has known stability limits. if you have a COA from the original batch, check if potency testing was included. that’s actual data. if not: the honest answer is it’s probably degraded, hard to quantify without assay data. it may still do something, but “still looks clear” isn’t the evidence you need for that conclusion.
the sterility/potency split is the right frame, and BUD-as-vouching-threshold is the part most people miss. one thing i’d add to the “may still do something” line: sermorelin’s degradation pathway isn’t kind to its activity. the first couple residues at the N-terminus are what binds GHRH-R, and they’re also what gets clipped first under hydrolysis, so once degradation is meaningful you’re not losing potency gradually so much as cleaving off the part of the molecule that does the work. fragments downstream of that cleavage don’t substitute well. that’s different from peptides where the active region sits in a more buried loop and partial degradation still leaves a working fraction. agree the COA is the only way to actually quantify it. without one, the honest answer is closer to “probably not doing what you think” than “reduced potency.”
“the first couple residues at the N-terminus are what binds GHRH-R” is exactly what the 90-day BUD window on sermorelin compounds is accounting for - GRF peptides as a class have that exposed terminal vulnerability, which is a big part of why the stability profile is tighter than something like a more folded peptide where the active region has some structural protection baked in. from the compounding side, HPLC purity testing would actually catch this specific degradation pattern bc N-terminal cleavage shifts the retention time - you’d see the parent peak eroding and fragment peaks appearing as separate resolved signals, not just a gradual broadening of the same peak. that makes a COA with purity data unusually informative here, more than it would be for some other compounds where degradation products are harder to resolve chromatographically. still doesn’t tell you what the potency curve looks like six months out, but original lot release data at least gives you a baseline to reason from rather than guessing off appearance.
“separate resolved signals” is the part i’d push on. that’s true for some N-terminal clips on a stability-indicating method that’s actually been validated for the degradants you care about, but it’s not automatic. small residue losses (loss of Tyr1, say, or a single deamidation at Asn8) can shift retention by a tiny amount on a standard RP gradient and show up as a shoulder on the parent peak rather than a cleanly resolved signal, especially if the column has some miles on it or the method was tuned for release purity rather than for stability indication. compounders’ release HPLC methods are usually the latter. they’re built to confirm the vial left the pharmacy at 95%+, not to deconvolute six months of degradation products. the other thing is deamidation and oxidation products tend to elute very close to parent on most RP methods. you generally need orthogonal stuff (LC-MS, an IEX run, or at minimum a stability-indicating method that’s been challenged with forced degradation samples) to actually quantify them. on a vanilla COA you might not see them at all. agree that lot release data is more informative than vibes, but worth flagging what it actually tells you: t=0 purity. it gives you a starting point, not a curve. without a stability study on that specific formulation (which compounders almost never do in-house, they lean on USP <797> generic BUD assignments or referenced literature for the API), six months out is still extrapolation off a single timepoint. the slope is the thing you don’t have. so “unusually informative” slightly overstates it imo. it’s better than nothing, and yeah GRF peptides chromatograph reasonably well compared to some other classes, but the COA mostly tells you the vial was clean when it shipped and that the parent peak resolved fine then, not that the method would necessarily catch the specific degradation pattern OP is now six months into. ymmv a lot depending on how thorough the compounder’s QC actually was.