OP here — wow, did not expect this much response! Thank you all for the thoughtful replies on Magnesium supplementation.

To answer sophie_paris: I started tracking everything in a spreadsheet from day 1.

Quick update: I will post a proper update thread soon. Thanks again for the evidence-based discussion — this is exactly why I posted in a science-based community. 🙏

Adding my data to this Magnesium supplementation discussion:

Protocol: Semaglutide 2.4mg/wk, resistance training 3x/wk, protein 1.6g/kg/day.

Agreed. My doctor said the same thing about Magnesium supplement.

Slightly tangential to Magnesium supplementation but Dr.RheumBOS reminded me — has anyone else noticed changes in their alcohol tolerance?

I know it is not exactly on-topic but it seems related enough to ask here rather than starting a new thread. Apologies if this has been covered — I did search first.

+1 to Dr.DermMIA. Especially the point about "Thank you all for the thoughtful replies..." — I have seen the same in my own experience with Magnesium supplementation.