I'm getting hard lumps at my injection sites that last for DAYS. Small, about the size of a marble, slightly red, and tender to the touch. This is happening at almost every injection site (I rotate between abdomen and thighs).

I'm on tirz 7.5mg, using the Mounjaro KwikPen. The lumps appear within a few hours of injection and take 5-7 days to fully resolve. By the time one goes away, I'm injecting again and getting a new one.

Is this normal? Should I be concerned? Any tips to prevent or minimize them?

Injection site reactions (ISRs) are reported in 3-7% of tirzepatide patients in clinical trials. What you're describing sounds like a local inflammatory reaction, which is the most common type. A few things to consider:

Technique tips that can help:

• Let the pen warm up. Take it out of the fridge 30 minutes before injection. Cold medication is more likely to cause local reactions.
• Inject slowly. With the KwikPen, hold the button for a full 10 seconds after you hear/feel the click, even though the instructions say 5. Slower delivery = less tissue trauma.
• Rotate sites thoroughly. Don't just switch between "abdomen" and "thigh" — use different spots within each area. At least 2 inches from any previous site. Use all four quadrants of the abdomen.
• Don't inject into scarred or lumpy tissue. If you keep hitting the same spots, lipodystrophy can develop, making future reactions worse.
• Ice the area for 2-3 minutes BEFORE injection (numbs the area) and for 5 minutes AFTER (reduces inflammation).

If the lumps are growing in size, extremely painful, warm to touch, or showing streaking redness, see your doctor — that could indicate infection or a more significant reaction.

I am definitely not letting the pen warm up first 🤦‍♀️ I pull it straight from the fridge and inject immediately. That might be a big part of the problem. Going to try the warming tip and the icing trick this week.

RN here. In addition to the tip aboves:

• Pinch technique matters. If you're very lean, pinch a fold of skin and inject into the fold. If you have more subcutaneous tissue, you might not need to pinch. Injecting too deep (into muscle) or too shallow (intradermal) both cause more reactions.
• Don't rub the injection site after. Gentle pressure with a cotton ball is fine, but rubbing can increase local inflammation.
• Consider the back of the upper arm as an injection site if you have someone who can help. It's often better tolerated than abdomen or thigh for people prone to ISRs.

The marble-sized lumps that resolve in 5-7 days are annoying but not dangerous. It's your immune system reacting to the peptide depot in the subcutaneous tissue. Some people are just more reactive than others.

I had the same issue and solved it by switching to compounded tirz in vials with insulin syringes. The thinner needle (31g vs 29g in the KwikPen) and ability to control injection speed made a HUGE difference. No more lumps.

Not saying everyone should switch to compound, but if the pen is causing persistent ISRs, it might be worth discussing with your provider.