In the Ming and Qing Dynasties, gentry women used their own hair to embroider images of the Bodhisattva Guanyin (also known as Kannon or Avalokitesvara). Embroidery of Buddhist images was seen as a highly meritorious activity, as it was very labor intensive- while a painting could be produced with a few brushstrokes, to embroider an equivalent image would take thousands of stitches. The repetition required in embroidery also heightened its religious value. A devotee embroidering an image could transcend the self through intense focus on the needle, not unlike someone reciting a Sutra (and, fittingly, the Sanskrit word Sutra means "thread").
The use of hair to create embroidered Guanyin images deepened both their karmic and ritual value. In order to create the thread, hairs were plucked from the scalp individually, and then split into several thinner strands or woven together into thicker ones. This process was incredibly painful and laborious, but allowed the women to alter their state of consciousness and prove the sincerity of their devotion, as an almost ascetic practice, adding value to the already meritorious process of embroidering images. The use of hair to embroider further allowed women to achieve self-transcendence through an exchange: in return for their pain and dedication, they could literally embody the diety.
Sources
Li, Yuhang. Becoming Guanyin: Artistic Devotion of Buddhist Women in Late Imperial China. Columbia University Press, 2022.
HairQuest 2024, even if I missed the deadline a bit :)