Injection site reactions — March 2026

SarahChen_PharmD said:

Peptide degradation indicators for injection-site reactions — how to know if your medication has gone bad: Visual: cloudiness, particles, color change…

For those on injection-site reactions — a practical guide to injection site rotation. I use a 4-site system:

• Week 1: Right abdomen (2 inches from navel)
• Week 2: Left abdomen
• Week 3: Right thigh (outer, middle third)
• Week 4: Left thigh

Then repeat. This gives each site 4 weeks to recover. I mark it in my phone calendar so I never inject the same area two weeks in a row.

GenomicsKate said:

I have been getting a raised welt at the site that takes two or three days to settle, and it started long after I had supposedly got the technique…

Has anyone on injection-site reactions tried splitting their dose across two injection sites? My provider mentioned some patients do this at higher doses (2.4mg sema or 15mg tirz) to reduce injection site reactions.

I'm about to move to 2.4mg and want to minimize the lump that forms at the injection site.

CarlaRPh_TPA said:

For those on injection-site reactions — a practical guide to injection site rotation.

Injection site reactions and injection-site reactions: I was getting red, itchy welts at every injection site that lasted 3-4 days. Turned out I was allergic to the alcohol swab, not the medication!

Switched to chlorhexidine prep pads and the reaction stopped completely. If you're having persistent injection site reactions, consider this possibility before blaming the drug.

Following on from pete_nash — and this may be the naive question:

How would you tell the difference between that and the alternative explanation?

anna.melb_AU said:

Injection site reactions and injection-site reactions: I was getting red, itchy welts at every injection site that lasted 3-4 days.

Nurse here. I see both sides of injection-site reactions in my clinical practice.

I manage about 113 patients on GLP-1 agonists at our weight management clinic. The most common issue I see related to injection-site reactions is patients not being adequately informed about what to expect. Setting realistic expectations up front is everything.

Practical tips from the clinic floor:
• Rotate injection sites religiously — use a log
• Let the alcohol dry COMPLETELY before injecting
• Don't massage the injection site
• Keep medication refrigerated until use, then room temp is fine for up to 28 days