Is K18 or Olaplex better for bleached or over-processed hair?

Both have large, generally positive verified-purchase followings for chemically damaged hair, but they work differently. K18's leave-in mask is left in rather than rinsed and is marketed for fast molecular repair, while Olaplex's No.3 and No.0 treatments are pre-shampoo steps. Notably, K18's Amazon average (4.3) sits slightly below several Olaplex products in our pool, with some reviewers reporting subtler results, so it's worth treating it as one option rather than a guaranteed winner.