Beard regulations ???

[Skyway71]

...that's how I feel about beard as cushion at least, which is what I remember being cited as the main concern when I've seen the topic of facial hair in combat sports crop up before. But I can defnitely see other ways in which it could it be advantageous, or at least disadvantage to opponent. As a trap for sweat and debris that could really mess up an opponent in the clench by obscuring vision. Or by way of additional "splash" from the beard on punch impact. Maybe?

I've heard before that it's allowed just as long as it's trimmed a certain length and that the jawline can be seen. But like you said, if one were to have a beard in a fight and have a bloody mouth dripping and settling in the beard over the course of the fight that mess can't be good for the other opponent. And someone here mentioned potential of eye abrasions. I can see they made Broner & Tyson Fury shave beard completely off and if there is a rule on this, none of the profighters should enter the ring with it.

[Citizen Koba]

Just as a little addendum though I think the original rules on beards that were until quite recently still upheld in the ammys and may still be on the books for various governing bodies have a lot more to do with appearances and proprities that have carried over from previous eras than to any practical advantages or hazards a beard might confer.... although I did just run across a comment that stated one reason beards remained prohibited in the ammys so long was to make sure facial cuts and damage could be properly seen and assesed.

[Mammoth]

Something must be done about Jono Carroll........

[South Champion]

Conor McGregor didn't have to shave his beard for the Floyd Mayweather fight either.

Maybe you only have to shave it if your opponent protests the beard.

[_Rexy_]

Beard ban has nothing to do with cushion. It has to do with judges not being able to see if punches land flush on the chin, and the fact that a beard can be used as a weapon during clinches, rub it in the eyes, cut, etc.