Are Retin-A and Stieva-A the same?

Great question! In essence they are both the same chemical. TretinoinThe only real difference is that Retin-A is formulated in microspheres which allows for a more controlled and slower release meaning more chance of less irritation.
However many patients tolerate both quite well so if you’re tolerating Stevia I wouldn’t switch as it is less expensive.
On the flipside if you are irritated by both - which is also not uncommon - You may want to start with a good quality cosmeceutical retinol like Skinceuticals to build up your tolerance. Think of it like the gyn for your skin. You may need to start with a lower strength.
Retinols along with good quality vitamin c and sunscreen form a great base to anti-aging.
Next step from there would be radiofrequency an or non ablatove lasers like clearlift or clear and brilliant
Good luck