Yes. Once you've used any GLP-1, reaching noticeable effects from a different one or restarting the same one usually requires higher doses.
I'm wondering if it's typical to see reduced response to reta after a full year on tirz. I got solid results from low tirz doses and moved over to reta, but even with gradual increases the fat loss isn't matching what I expected. I'm at 4 mg after seven months, keep up with exercise and protein, and still see others reporting stronger results at lower amounts. I recently added mots-c and tesa hoping to target visceral fat. Any thoughts or suggestions?