Am I using fake tretinoin?

So I’ve used tretinoin (Retin-A) on and off for about 7–9 years. Back then I was using 0.025% , and even that made my skin peel and get that shiny, exfoliated look. I eventually tried 0.05% and even that felt strong. When I briefly tried 0.1% in the past, I had to mix it with moisturiser because it was too intense (may have also mixed 0.5% with moisturiser). My face would flake and get that classic tret “shine.” I originally used it for acne and hyperpigmentation. It worked pretty well, my acne reduced a lot and some pigmentation faded. Over the years I’ve been inconsistent. I’d stop for months (sometimes over a year), restart, stop again, etc. (also the website i used to buy it from shut down, i think i would buy retin-a) Recently I bought something called Tretigel 0.1% (branded "Winlife Pharma" on the tube. I’ve been using it for months now, probably close to a year (again using it on and off). I’m using the 0.1% straight, not mixing it with moisturiser, and I have zero irritation. No flaking, no peeling, no shiny exfoliated look. My slight acne has reduced a bit (i think) but I’m also 28 now, so I’m not sure how much of that is just age and also if i even had that much acne before or just in my imagination. (My pigmentation/scarring has gotten worse on 1 side of cheek but thats mainly from staph infection I had many months/1 year ago which caused a lot of breakout on face and body) I genuinely don’t know what to think. Part of me wonders if my skin has just completely adapted to tretinoin after all these years. The other part of me is thinking maybe this product isn’t legit, is under-dosed, or degraded/expired somehow. I store it normally (room temp).