What is the Origin of Hair Follicle Cycles?

The term is a direct combination of "hair follicle," the sheath and root of the hair, and "cycles," denoting the recurring sequence of events. The morphological changes corresponding to these distinct phases were systematically described by dermatologists and physiologists, establishing the foundation for understanding hair disorders like androgenetic alopecia.

What is the Mechanism of Hair Follicle Cycles?

The transition between these phases is tightly controlled by a complex interplay of hormones, growth factors, and cytokines acting on the dermal papilla and surrounding cells. Androgens, such as dihydrotestosterone, are known to shorten the anagen phase in genetically predisposed scalp follicles, leading to miniaturization. Conversely, certain growth factors prolong anagen, supporting robust hair growth; the entire mechanism ensures continuous, though asynchronous, hair renewal across the body.

Hair Follicle Cycles ∞ Area

Hair Follicle Cycles

Meaning

Hair follicle cycles refer to the precisely regulated, repetitive phases of growth, regression, and rest that each individual hair follicle undergoes independently throughout a person’s lifetime. These cycles are critical biological processes that determine hair length, density, and overall scalp health, profoundly influenced by systemic endocrine signals. The three primary phases are anagen (growth), catagen (regression), and telogen (rest).