I have naturally wavy, heavily highlighted, fine, thinning, damaged hair with tape-in extensions...
I've had good results so far with Iles Formula Scalp Booster, but it's a spray, not a dropper.
Iles Formula Mask, also love Philip Kingsley Elasticizer
Iles Formula
As weird as it sounds but I used to think that the tech that Valmonts boasts about +
Maybe Biosilk or CHI? Iles Formula also contains silk protein and is amazing, but expensive.
3rd, also Miriam Quevedo Glacial White Caviar Rescue Masque and Iles Formula Haute Performance Mask