Dr.ObesityMed said:

DEXA scan update relevant to lean mass: Scanned at months 0, 6, and 12.

Regarding lean mass: I accidentally injected my dose intramuscularly instead of subcutaneously last week (went in at wrong angle, too deep). Called my pharmacist — they said it's not dangerous but may absorb faster, potentially causing more GI effects.

Sure enough, had worse nausea that day. Lesson learned: pinch the skin properly and use the right needle length for your body composition.

A narrower follow-up, since the general answer is now clear:

What did you change at the same time, and can you separate the two now?

PeptideSynthNJ said:

Regarding lean mass: I accidentally injected my dose intramuscularly instead of subcutaneously last week (went in at wrong angle, too deep).

My endo's protocol for lean mass plateau: if weight loss stalls for 6+ weeks at current dose, we go through this checklist before titrating up:

1. Food diary review — is intake creeping up?
2. Protein check — minimum 100g/day
3. Activity audit — steps + resistance training
4. Sleep quality — poor sleep kills GLP-1 efficacy
5. Stress/cortisol management

Only after addressing all of these do we increase the dose. Often fixing one lifestyle factor restarts progress without needing more medication.

PeptideSynthNJ said:

Regarding lean mass: I accidentally injected my dose intramuscularly instead of subcutaneously last week (went in at wrong angle, too deep).

Back pain as a lean mass side effect: not from the medication itself, but from rapid body composition changes. Losing 63 lbs shifts your center of gravity and your core muscles need time to adjust.

Physical therapy has been essential. Core strengthening exercises (planks, dead bugs, bird dogs) daily for 10 minutes have eliminated my lower back pain. Your body is literally relearning how to carry itself.

PeptideSynthNJ said:

Regarding lean mass: I accidentally injected my dose intramuscularly instead of subcutaneously last week (went in at wrong angle, too deep).

Saving this. It is the first explanation that did not require me to already understand it. Printing the relevant bit and taking it with me.