Recently I’ve heard a radio ad for some local hair clinic claiming that they can use some laser (nearly painless) to replace hair. I’m guessing this is some new version of transplantation surgery. I also hear and see a lot of spots for laser hair removal.
So, do lasers remove hair or add hair? How do they do both? 
I don’t know about hair transplantation, but I would guess the hair removal is done by killing the follicle. It absorbs enough energy from the laser that it dies.
Laser definitely will remove hair, with greatly varying levels of effectiveness depending on a wide array of factors. Both Fierra and I have had lots of laser done (armpits, legs…other things), and have had great success.
I have never heard of lasering to increase hair growth. Statistically speaking, in some hair removal studies there are sometimes a very tiny number (< 2%) who see increased hair growth, but I think this is either a fluke or observer error, IMHO.
Okay, burning out follicles makes some sense, I suppose. But still no ideas on how lasers are used to make hair grow (or transplant new hairs)?
There are these laser combs that claim to be able to stimulate hair follicles into regenerating. Removing hair = higher doses
Search on laser hair comb, or read/look here: