Cloudy Reta - normal?

Hong Kong Yanpep International
Someone posted this on another thread - [URL='https://www.another forum Calculator | Free & Accurate Tool for Dosage & Reconstitution[/URL]
 
I had that issue with some bac water - mixed it up and it was cloudy right away, then cleared with buffer and went back cloudy. Tried pH strips, same number both ways. Finally switched to a brand I knew was solid and never had it again. Probably something in the water itself, maybe alcohol content or quality control. Easier to just stick with what you know works.
 
Reta going cloudy after a week at 37F is a known issue - several sources have had batch problems where the peptide aggregates at cold temps without actually degrading. The community consensus is to request a replacement rather than trying to warm and re-dissolve. If the vendor has been responsive on cloudy batch issues, it's worth reaching out with the lot number.
 
The compound-specific compatibility issue with saline BAC for Reta is one of the more important reconstitution details - the sodium chloride content reacts with Reta's charged residues in a way it doesn't with Tirz or Sema. Standard BAC water without sodium chloride is the right carrier for Reta; the same saline BAC bottle that works fine for Tirz should not be used interchangeably for Reta
 
What was the purity reading?

Bought some of the third compound that I believe came from this same production run. Actually mixed one vial right away and didn't look closely before injecting, so it could've already been cloudy, not sure. Was totally fine afterward.

But then last week when I mixed another and actually paid attention, it looked cloudy, so I tossed it. Ended up using a backup vial I'd saved from a different batch instead. Then this week grabbed still another vial from that same carton and got the exact same murky result. Using standard pharmaceutical-grade diluent the whole time.

Was considering sending a vial off for lab testing but not sure it's worth the cost. Still have two full boxes of this batch left.

Mine came topped with those pale blue see-through lids, matching what's pictured elsewhere in this thread. Just genuinely frustrated. Thought I'd found a supplier I could trust.
 
Follow-up: two MOTS-C vials mixed with NaCl BAC both turned cloudy. Vial one I misread as fogging on the pen cartridge, so I injected the whole 3mL without any problem (cloudiness showed only after I pulled the cart). Vial two clouded up again, and since it looked cloudy the next day, I'm leaving it. It would probably be harmless like last time, but then I was ignorant, and now I'm not, so I won't gamble just to avoid wasting it.
 
Interesting. I was told acetic acid can help a cloudy reta. My next vial came out clear so I never tested it. They also suggested bacteriostatic saline as one more solution.
 
Same thing hit me on my initial Reta vial. Straight from the fridge it looked cloudy, then turned crystal clear at room temp. I'm nearly sure the cause was not venting the vial properly during reconstitution, since it was my first time and I missed the venting step. Another vial out of that kit, prepared using that identical bac water, had no problem, and that one I vented properly. Anyway the cloudy vial worked perfectly, so I wouldn't worry.
 
Chiming in since several people have raised this. Here's the chemistry, in case it helps anyone now or later. Most likely the cloud comes from pH. Leftover TFA salts from production, which shouldn't be present, probably sit in the powder, and adding BAC water pushes the combined acidity exactly onto reta's isoelectric point. Molecules lose charge, clump and precipitate, and that precipitate is the cloudiness. Easiest first check: the BAC water. Even the maker's own spec allows a pH figure at any point between 4.5 and 7.0, which is broad. A bottle near the acidic end can crash a TFA-loaded peptide, while one near the top of the range may dissolve it crystal clear. Swapping in BAC water from another lot or bottle is an inexpensive experiment.
 
Cloudy straight out of a 37F fridge is often just the peptide coming out of solution, and it can clear as the vial warms. If it stays cloudy, or you see particles or discoloration, toss it. Bac water is good for 28 days after first puncture, and a reconstitution calculator covers the concentration math.
 
kcryland's isoelectric point explanation is the right frame, and there is one number in it that is worth writing down because it decides most of these cases before anyone touches a filter or a buffer.

Bacteriostatic water is not one pH. The USP spec for Water for Injection permits 5.0 to 7.0, and the benzyl alcohol only helps the low end of the useful range. A vial that tests at 5.2 and a vial that tests at 6.8 are both "in spec" and are not the same solvent. Retatrutide sitting on residual TFA is already acidic; add a 5.2 water and you land near the isoelectric point and it drops out. Add a 6.8 water to the same powder and it stays clear. Same peptide, same technique, opposite outcome. That is why "it worked with the other bottle" keeps showing up in this thread.

Two cheap checks before assuming the batch is bad:

Put a pH strip in the water before you use it. Not after. The number you want is roughly 6.2 to 7.0 for a peptide carrying TFA. If your bottle reads 5 and below, that is the variable, not the peptide.

Then split the evidence. If the same powder goes cloudy in acid water and clear in neutral water, the powder is fine and the water is the problem. If it clouds in every water you try, and it also looks off as a dry cake, then it is the lot, and that is when you ask for the certificate and the measured fill rather than a replacement.

That last point is the gap in this thread. Clearing up tells you it dissolved again. It does not tell you how much came back. When peptide precipitates and re-dissolves, a fraction stays on the glass and in the precipitate, and if you filtered it you lost more on purpose. Anyone who treats a cleared vial as "concentration unchanged" is quietly underdosing. Reconstituting to a known volume and reading the certificate's measured mg is the only way to know what is actually in the syringe.

Small note on where this kind of question gets answered properly: a few of us run a group where people post their lot numbers, certificates and measured fills against what they paid per milligram. It is mostly the boring accounting side of this hobby rather than vendor chat. Link is in my profile if it is useful.
 
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