Will Wearing hats after FUE effect hair growth?

Wearing a hat 6 weeks after your FUE should not affect the transplanted grafts anymore than your regular hair.  After about 5 days, transplanted grafts are part of your skin and living tissue.  I allow my patients to wear loose fitting hats 5 days after the procedure.  After 2 weeks they can wear a hat as much as they want.

Wearing hats do not affect hair loss.  Wearing hats do not affect hair growth.  But if your doctor says don't wear hats, then follow your doctors advice.

After two weeks post procedure there is nothing you can do to either help or harm the follicles unless you bump your head.  Patients are free to go back to a normal routine at the two week mark post procedure. 

One of the biggest myths or misconceptions is that wearing hats deprive the scalp of oxygen. That's not how it worksWearing a hat is ok if the first two weeks is fine provided it is put on and taken off with extreme care. After 2 weeks, a hat can be worn any way you likeHairs get their oxygen from blood vessels inside the scalp - not from diffusion from outside to inside

As far as we know, most of the body depends on oxygen that is processed via the lungs so your scalp is not going to be deprived by a hat.  No science has shown hats to cause or be related to hair growth. After a procedure, they do not like hats because they mess with healing tissue but not because of the oxygen.