Injection Site Reactions Starting after 3 months

The original poster began seeing 48-hour delayed reactions to Reta after three months of use, similar to prior GHKcu welts, despite rotating sites and trying fresh vials, new BAC water, antihistamines, and a travel break. Replies suggest testing BAC water alone, note these are likely localized allergic responses that can develop after immune sensitization, and recommend longer needles for deeper fat placement since skin has more immune cells. Antihistamines are unlikely to help delayed cell-mediated reactions, and while common with GLP drugs they are usually harmless without systemic symptoms.

• Reactions can begin after sensitization lasting days to years
• GLP injection site issues occur in roughly 5% of cases per studies and are mostly local
• Deeper fat injection may reduce skin-based immune responses
• Delayed 48-hour reactions point to cell-mediated hypersensitivity where antihistamines are ineffective
• Antibodies to these drugs form often but rarely neutralize effects

Whether switching compounds or continuing will resolve the reactions long-term

Nothing here is advice.