In an article published in The Conversation, experts detailed how hormone- or treatment-induced changes may affect the hair. They explained that the normal development cycle of hair involves a growth phase of several years, followed by a transitional phase and a resting phase in which the hair stops growing and falls out of the hair follicle after a few months. They noted that events such as puberty, pregnancy, the receipt of chemotherapy, and aging may all influence the texture, thickness, follicle shape, and color of hair, as well as disrupt its natural development cycle. The experts revealed that heightened levels of estrogen, progesterone, and prolactin may lengthen the resting phase during pregnancy; however, when hormone levels decrease following birth, the hair trapped in the resting phase may fall out all at once. In individuals with genetic traits related to both straight and curly hair, hair may appear to be wavy; during puberty or pregnancy, hormonal changes may increase the function of certain genes and boost the curly appearance of the hair. Further, chemotherapy is capable of killing and/or altering the shape of hair follicles, resulting in hair loss or different hair texture after regrowth. The experts emphasized that as individuals age, the levels of thyroid hormones responsible for keratin production as well as estrogen and androgen may change—leading to dry, brittle, and gray hair, as well as balding.
January 31, 2024