155 days post op. Can I use Sebamed anti hair loss ph 5.5 shampoo?

It is best to ask your surgeon about post operative care as each doctor has their unique regimen.  You can use any product few weeks after surgery.

You can use anything you can anything at this point. Its only the time just after the transplant that you need to worry about the grafts and medicated shampoos.

At 155 days after any surgery on the scalp, you can do anything you did prior to the transplant as everything is now healed