hair metal is the most fucking posturing music has ever had to deal with
it was a bunch of pop artists who couldn't admit they were writing/playing pop music because it wouldn't be 'metal'
fuck that, if you're going to play pop music then do it
fucking embrace the bop
Glam Metal is a tolerable term. Hair Metal is completely crucifying. Perhaps, some day, a writer will refer to Punk as Snot Rock and have that linger for decades. Nobody called this music "hair metal" in the early 80s...or the mid 80s...or the late 80s... or the early 90s in fact I never heard it until the mid 90s and I definitely don't recognize it as an actual musical term. It's a b.s. phrase cooked up as a derogatory comment. The holy trinity of glam metal influences are as follows:
1) Van Halen--Biggest contributions: guitar technique, frontman persona, background vocal style.
2) KISS--Biggest contributions--stage design and pyrotechnics, lyrics about decadent rock lifestyle, template for making heavy songs poppy.
3) Cheap Trick--Biggest contributions: outlandish guitar designs, strong pop melodies, adding mugging goofiness to heavy rock, prototypical "pretty" blonde male singer.
Other major influences in creating the style would include Aerosmith, AC/DC, New York Dolls, Sweet, and of course Led Zep and Deep Purple. I would go further and say that Van Halen may be to metal what the Velvet Underground was to alternative rock. They literally launched several sub-genres of metal on their own. There were very few viable metal acts prior to Van Halen's first album. Within 3-4 years, metal was all over the place, with most of the bands bearing much more of a resemblance to Van Halen than Black Sabbath, although many of these acts that followed also owed a heavy debt to Judas Priest. Van Halen inspired the US metal stuff. They also inspired a legion of guitarists. Their influence remained on all the hard rock/glam rock/glam metal/stuff to get your girlfriend wet stuff the major labels and MTV loved. Also Michael Schenker was a huge influence on glam metal. You don't get that 8th note riff style being so prominent in the music without him. In that sense, I think a lot of 80s heavy metal guitarists grew up on UFO.
But also big influence on metal was still British. Judas Priest, Iron Maiden, Venom, Motorhead and rest of NWOBHM which inspired the thrash movement.