How long after a hair transplant can you wear a wooly hat?

The grafts are pretty secure and a wool hat should not hurt the grafts after 2 weeks.  The only issue would be sensitivity to the fabric as the skin is delicate in the transplanted area and healing.  Id refrain from wearing the hat for extended periods but covering your head for short amount of time after two weeks should be fine.

Please consult your post operative instructions.  I recommend that you wait to wear any kind of fabric hat that may pull out the grafts when it is removed until 14 days.