What's That Title???? discussion

I read a lot of books from 2015-2018 and there’s one book ive been trying to find since.
I remeber the front of it was like a double barrel title so it was like this:
ABCDE
abcde
ABCDE
abcde
ABCDE
I also only remember some of it the things that i remeber is it was a book about a girl who was living somewhere with her family it was almost like a facility… they took vitamins everyday this is what i remeber until she found out the vitamins weren’t needed
She fell in love with someone else who lived at the facility and i remeber they escaped.
This may not be a lot for you to work on but please please help even if u just find book covers that are the way i have explained…
Thankyou

I think it may have been made into a movie.
I am remembering a movie trailer with that story line.
There was a movie called The Island with a similar plot but that not it. Another movie along that line is called Voyager. Teenagers on a space ship taking "vitamins" that keep them docile and they stop taking them and love and chaos breaks out.
Definitely(?) Young Adult book.
That all I got.

I am hear looking for the tile of a thriller suspense book of a couple on a sailboat being chased by a serial killer or just a killer on a fishing boat or a tugboat. I remember at one point the husband was locked in a cage in the back of the killers boat.
Any help would be appreciated. I have search all the areas online and even asked 2 librarians.