That is a fast response. I had a "response" very quickly too, but it was in mood and energy levels. I think I cleaned 3 closets out in the first 2 weeks back then! LOL

My knee was inflamed and swollen and the MRI said had normal cartilage...

But I was at the same time shopping for my son after vacation, for college stuff. It was a big deal to get him settled. I had all his stuff done before vacation. He and his dad came home early and left me up there alone, at the end of August. Well, they left the bag of stuff (dorm HBAs, etc) outside the room in the hall and went to eat or something and someone stole it. So when I got home I had to replace it all in 2 days, because I was slated to several jobs immediately! I walked into WalMart, and the new SAMe was on an endcap sale island for about $18.00 for 15 of them 200mg each. It was a mega sale. I knew about it but at that time, the therapeutic doses published were 800mg a day for it and that would be over $4.00 a day. So I was waiting for a price decrease. But since WalMart had NatureMade there, I decided to try it anyway. By the 5th day on it, I KNEW it was for me!

Luckily for me, Costco just opened in our area and had them in 90 tablet boxes at quite a savings. But now, of course, we know
1) you don't really need those high doses
2) it is so much more affordable...no excuse to not try it.

It took much longer to affect my arthritis... but it did. It helped me thru the menopause too. Kept me sharp when I had to do 6 different computer systems a week, in my contingent assignments. (this was a huge problem for me at the time).

So stick with it, and if you don't have the hyper issues, that means you are tolerating it better than average.
I think early on you are feeling the improvements in pain perception, and that is what you sense as helping the arthritis.
When the swellings go down...that will be a bigger moment.