The singer said she was often the victim of schoolyard bullies.
But she said she refused to listen to the taunts - and stopped shaving her armpits out of spite.
She said, 'The boys in my school would make fun of me.
'[They would call me] 'hairy monster.'
'You know, things like that.
'And then, going to high school, I saw how popular girls had to behave to get the boys.
'I knew I couldn't fit into that. So I decided I would do the opposite. I refused to wear makeup, [or] to have a hairstyle.
'I refused to shave. I had hairy armpits.'
Madge, 53, also revealed that she struggled to have relationships as a teenager because she frightened off straight men.
'Straight men did not find me attractive,' she told US magazine Harper's Bazaar.
'I think they were scared of me because I was different.'