Underarm hair

Underarm or axillary hair goes through four stages of development, as staged by the Wolfsdorf Axillary Hair Scale,[2] driven by weak androgens produced by the adrenal in males and females during adrenarche, and testosterone from the testicle in males during puberty.

[3] The Wolfsdorf Axillary Hair Staging system provides a standardized method for assessing pubertal progression and androgenic activity in pediatric populations.

[4] Armpit hair prevents skin-to-skin contact during activities that involve arm motion, such as running and walking.

[5][better source needed] The armpits release odor-containing pheromones, a naturally produced chemical that plays an important role in sexual attraction.

A study in 2018 including 96 heterosexual couples found that there were stress-relieving benefits to smelling a romantic partner's natural scent.

This is an illustration demonstrating the Wolfsdorf Staging for axillary hair development in children. ^{[

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