A reconstituted vial is one or two milligrams of peptide in a couple of millilitres of water. Buyers will pay to have the milligrams tested and never think about the millilitres. The founder of Janoshik has started testing the water because customers asked him to, and what his lab found in the cheap bottles is the most practical thing in the whole interview.
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The interviewer's concern was the generic bottles sold alongside peptides, which he had seen come back with no alcohol in them. The lab's experience matched.
We're testing a lot of those recently. People are actually concerned with it more and more. It is a pretty good point, and we've seen everything. We've seen a lot of zero benzyl alcohol in the water. We've seen unsterile. We've seen concerning endotoxin results.
His framing of why it matters is proportional rather than alarmist. A vial of peptide passing endotoxin with a few units in it is undone by water that carries more.
It's really nice if you have five thousands of endotoxin units in a vial of peptide, but then your bacteriostatic water has ten units per millilitre. It doesn't really matter how much the peptide was, right?
(The auto-caption garbles the first figure; the sense is that the peptide's own endotoxin level stops mattering once the water contributes more. The comparison is what he is making, not the exact numbers.)
The part that surprises American readers: the preservative that every US reconstitution guide treats as mandatory is simply absent from European practice.
In Europe we don't use bacteriostatic water at all. We just use either saline for injection or sterile water for injection, which is just pure water really.
The benzyl alcohol, it's not used over here I believe because the likelihood of it helping is roughly the same as the likelihood of it causing a local issue. The benzyl alcohol itself can cause some irritation.
The interviewer then asked the question most readers want answered, whether sterile water plus a fridge for 28 days is acceptable:
So according to Peter from Janoshik, you can reconstitute your peptides with sterile water and keep those for 28 days in the refrigerator, no problem.
Yeah, sure. There's very little difference from using bacteriostatic water, from what I can tell.
He is explicit that this is a personal opinion, not a lab finding, and it is a short one.
What I would do, but that's just personal opinion of mine: I would get brand name, like pharmacy sterile water or saline for injection. Check if it works. For example, some peptides might not really like saline.
I'll check which works with the peptide I'm using, it dissolves clearly, nicely, and then generally if the saline worked, then the saline is the best, because the saline has the least risk of it causing some sort of local reaction.
His lab's own practice is ultra-pure water (44:03, 45:08), the thing sterile water for injection most closely resembles. None of this makes bacteriostatic water wrong. A brand-name bottle from a pharmacy does what it says. The warning is about the unbranded bottles bundled with vials, where the label may be the only thing that is bacteriostatic about it.
Water is the half of a reconstituted vial nobody checks; the other half is the subject of this site. The 5% of samples that arrive at his lab short or wrong (46:21) are caught by a certificate for your lot that the laboratory itself will confirm, the first check in how to read a peptide COA. Once water is in, the limit on an opened vial is growth rather than degradation, which is the storage guide. And the one handling rule everyone argues about turns out not to matter: you can shake it.
The water is part of the product. A vendor that ships a lab-verified vial and a no-name bottle of "bacteriostatic water" has verified half the kit. Brand-name sterile water or saline from a pharmacy costs a few dollars and removes the half nobody tests. For the vial itself, the same rule as always: a certificate for your lot that the lab will confirm, from a vendor whose score you can audit.
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Both are sterile water for injection. Bacteriostatic water additionally contains 0.9% benzyl alcohol, a preservative meant to slow bacterial growth in a vial that is punctured more than once. Sterile water has no preservative and is intended for single use. Saline for injection is sterile water with 0.9% sodium chloride and also has no preservative.
Yes. Janoshik's founder says that in Europe bacteriostatic water is not used at all; labs and clinics reconstitute with sterile water or saline for injection, and his own lab dissolves peptides in ultra-pure water, which sterile water most resembles. Asked directly whether a vial reconstituted with sterile water and kept in the fridge for 28 days is fine, he answered yes, with very little difference from bacteriostatic water that he can tell.
His lab has been testing it more and more because buyers asked, and it has found bottles labelled bacteriostatic with zero benzyl alcohol, bottles that were not sterile, and endotoxin levels he called concerning. His own preference is brand-name pharmacy sterile water or saline for injection. The point he makes is proportional: a vial of peptide with low endotoxin means little if the water added to it carries more.
He does not claim it damages the peptide. His reservation is about the person, not the molecule: he says the likelihood of the preservative helping is roughly the same as the likelihood of it causing a local issue, since benzyl alcohol itself can irritate. That is why Europe gets by without it, in his telling.
His personal answer, given as an opinion rather than a lab finding: brand-name sterile water or saline for injection from a pharmacy, then check that the particular peptide dissolves clearly in it, since some do not like saline. If the saline works, he prefers it, because it has the least chance of causing a local reaction. Whatever the choice, an opened vial still belongs in the fridge and should not be kept for months, which is covered in the storage guide.