Underarm hair

Underarm or axillary hair goes through four stages of development, as staged by the Wolfsdorf Axillary Hair Scale, The Wolfsdorf Axillary Hair Staging system provides a standardized method for assessing pubertal progression and androgenic activity in pediatric populations. Similar to Tanner Staging for pubic hair, it classifies axillary hair growth into four stages: • Wolfsdorf Stage 1 – No axillary hair • Wolfsdorf Stage 2 – Sparse, soft hair • Wolfsdorf Stage 3 – Coarser hair with increased volume • Wolfsdorf Stage 4 – Full adult-like axillary hair The importance of human underarm hair is unclear. It may naturally wick sweat or other moisture away from the skin, aiding ventilation. Colonization by odor-producing bacteria is thereby transferred away from the skin (see skin flora). File:Armpit by David Shankbone.jpg | Male axilla File:Womans armpit.JPG | Female axilla File:Armpit of a Teenager,in developement,Mar 2013.jpg | Axillia of a pubescent male, note the short, stray hairs characteristic of this stage (Wolfsdorf 2) ==Function==

Reducing friction Armpit hair prevents skin-to-skin contact during activities that involve arm motion, such as running and walking. The same applies to pubic hair. Spreading pheromones The armpits release odor-containing pheromones, naturally produced chemicals that play an important role in sexual attraction. Armpit hair traps odor, making the pheromones even stronger. A study in 2018 including 96 heterosexual couples found that there were stress-relieving benefits to smelling a romantic partner's natural scent. ==Impact of hair removal==

Effect on odor А 2012 study on the impact of hair removal on odor found that shaved armpits were rated the same as unshaved armpits. Chemical absorption A 2017 study on chemical absorption from deodorants as a result of hair removal showed an increase in chemical absorption from .01% to .06% where skin has been damaged by recent shaving. A 2003 study on aluminum antiperspirant usage and the age of breast cancer onset tentatively concluded that "underarm shaving with antiperspirant/deodorant use may play a role in breast cancer." However, later studies have disputed this and found no significant increase in breast cancer among users. == See also ==