What about armpit hair? Such as the development of it with pictures.
Armpit hair is more variable than you might suspect. Some lineages have very little to no armpit hair, even as full-grown adults (8% of Asians, 4% of African, 13% of Indians or Pakistanis). Other lineages have very dense and thick armpit hair.
Like all other body hair, the skin is covered with fine, nearly colorless vellus hairs.
As you mature, the hair follicles respond to the testosterone in your system and begin changing to terminal hairs. First, the hairs get longer, then they start taking on more color and getting thicker in diameter. Not all the follicles change at the same time, so at first, the hairs are sparse and later fill in.
The color of your hair is also going to impact your perception of how much hair you think you have. Dark-colored hair on a light-skinned person is going to be more noticeable than dark-colored hair on a dark-skinned person or light-colored hair on a light-skinned person.
- “Armpit Hair,” Men’s Health Handbook.