BAC water not dissolving Eloralintide?

That sounds like a bad sign and probably means what you received is not the real compound. Fillers that are commonly added should still go into solution without trouble, so complete failure to dissolve suggests something else is in the vial. Without knowing the contents it is probably unwise to use it. A pH mismatch with the BAC could be a factor but the filler should still dissolve anyway. Any pictures available?

I recently tried a 5 mg kit of the same compound. It did dissolve in BAC water but I noticed no effects after injecting it. Stacking it with another peptide did not change the outcome. Not sure what to do with the rest of the vials.

It is hard to diagnose anything without covering the basics first. Using BAC water with the correct pH and having lab results that confirm the actual contents are the minimum requirements. Skipping those steps leaves everything to chance.

What does the COA actually list?

Just to be clear, are we talking about freeze-dried material in a vial or loose raw powder? Also how much BAC water was added?

This points to the material being fake. Can you share a photo of the vial contents? Good product normally goes into solution fine with ordinary BAC water. Gentle rolling or swirling of the vial is enough; anything more aggressive is not recommended.

My second vial of the compound went into solution crystal clear within about twenty seconds using one milliliter of BAC water and simple gentle inversion, exactly like the first vial. That makes me question what you received.

What is the pH of the BAC water you used?