Iranian police had warned barbers not to give men Western hairstyles or use make up on them.
The move is part of an unusually fierce crackdown on what is known locally as bad hijab, or un-Islamic clothing, that this year is also targeting men.
Hair stylists have been warned that they could lose their licences if they do not comply.
Police say that as well as avoiding Western hairstyles and make up, barbers should not pluck customers' eyebrows.
Some young boys in Iran sport very wild hair styles, using gel to make their long hair stand on end in a fashion not seen in other countries.