Red patch, suspecting the bac water

The original poster experienced identical hot red patches and burning from two different peptides mixed with the same bac water, something that had never happened before. Several users point to non-pharma-grade bac water as the likely culprit and recommend switching sources or testing pH, while others note that reta itself can trigger delayed histamine reactions. Suggestions include injecting bac water alone to test, filtering peptides, or trying antihistamines, though results vary. The user later reported the reaction stopped after moving injection sites to the glutes.

• Same red patch reaction occurred with both GHK-cu and reta when using one bac water batch
• pH of the suspect bac water measured at 5.5, which falls inside the typical 4.5-7.0 range
• Reta can produce its own delayed histamine response independent of the solvent
• Filtering peptides or switching to a different bac water source are common troubleshooting steps
• Site rotation to glutes resolved the visible reaction for the original poster

Whether an antihistamine like Benadryl reliably stops the reaction; one user says it works every time while another reports zero effect.

Whether the peptides themselves, the specific bac water batch, pH, or fillers are the true trigger, and whether 5-micron blunt-fill needles are adequate for sterile filtration.

Nothing here is advice.