Thought I would chime in, as I found this thread in a Google search.
GLP-1 has an extremely short half-life, therefore an agonist is required for effective therapy. Also Saxenda is of this class and is approved for weightloss. Thyroid cancer was observed at higher rates in rats relating to C cells. Humans have significantly fewer C cells so it is not anticipated to be likely in humans.
Ok I started this 2 weeks ago for diabetes. Which I was diagnosed in my 20's and managed via diet and exercise only, and have had modest control. Prior to my 20's I was an avid athlete and worked out close to 14 hours per week. Did some lifting and could curl 120 for 10 sets of 10. Even with all of that I only ever had modest size and no-one would believe how heavy I lifted for my size until I did it in front of them (think myostatin). Obviously I am out of shape but would be called skinny fat being about 195 at 6'4. Needless to say I have had muscle atrophy. I also think I probably have a genetic defect pertaining to glp-1 as my son is diabetic and diagnosed at 15, and how extreme I am reacting to treatment.
Anyway my experience. Took my starter Ozempic which is the injectable version of the drug the other guy is taking. My blood sugar the next day was already averaging 20 less than the day before. I had mild side-effects so took my second once weekly dose at 4 days. Now it has been 11 days averaging 50 less on bloodsugar and I am going to bump to full dose tonight because I have tolerated it so well. I also have noticed fat loss on my abdomen and chest.
As for muscle gain changes, that is how I found this site. My muscles are noticeable larger, fuller, and more pumped, enough that I went searching the past 2 days. As stated I know I have had significant atrophy from my youth and am out of shape, and would imagine that is where the gain is coming from. I have been having to drink 2-3 gallons of fluids a day, and I am urinating less. It feels as though my muscles are increasing vascularly and interstitionally. The one side effect which makes sense is that I have lost most of my strength/endurance. I can only activate my muscles briefly before they fail. I literally could not do 1 full push up or squat, but initially had full strength. However my energy is up and I honestly feel great. Overall, it feels like my muscles have the strength but not the ability to maintain exersion. Overall, I am shocked at the changes in 11 days, and excited due to the decrease in pain, and increase in energy.