If a lot of them are good

Are these correct:

1) I don't know if a lot of these pills are really good for me. I have doubts about pill A, pill B, pill C, pill D and pill E. I know the other two are good for me.

2) I am not sure that a lot of these pills are really good for me. I have doubts about pill A, pill B, pill C, pill D and pill E. I know the other two are good for me.

'A lot of these pills' refers to a specific subset of the pills. I have specific pills in mind.
As regards a lot of these pills, I am not sure that they are good for me....

Gratefully,
Navi.