Pubic hair, also known as terminal hair, is a thicker, coarser type of hair that develops in the genital region, typically beginning around puberty. The question of whether this hair stops growing is often raised because it appears to reach a certain length and then pause, unlike the hair on the scalp. Pubic hair does not grow indefinitely, but instead follows a specific, genetically programmed cycle that limits its maximum length. This phenomenon is a perfectly normal biological function dictated by the hair follicle’s predetermined timeline.
The Universal Hair Growth Cycle
All hair on the human body cycles through a pattern of growth, transition, rest, and shedding. This process is divided into four distinct phases that repeat over the life of the hair follicle.
The first and longest stage is the Anagen phase, the period of active growth where cells in the hair root divide rapidly to form new hair fiber.
Following the active growth period is the Catagen phase, a short transitional stage lasting about two to three weeks. During this time, the hair follicle shrinks, and the hair detaches from the blood supply, marking the end of growth.
The hair then enters the Telogen phase, a resting period that typically lasts for a few months, where the strand remains anchored but is no longer growing. The final stage is the Exogen phase, the shedding phase where the old hair is released from the follicle to make way for a new Anagen hair. Since each hair follicle operates independently, the body avoids shedding all its hair at once.
Why Pubic Hair Reaches a Maximum Length
The perceived “stopping” of pubic hair growth is directly explained by the short duration of its Anagen phase. While scalp hair can remain in the active growth phase for two to seven years, the Anagen phase for pubic hair is significantly shorter, lasting only about three to four months. This brief period of active growth limits the ultimate length the hair can achieve before the follicle signals the end of the growth stage.
Once the follicle shifts into the transitional Catagen phase, the hair shaft stops elongating, and the maximum length is established. The majority of pubic hair follicles are in a resting state at any given time, with estimates suggesting that around 70% of the hair in the pubic region is in the Telogen phase. This high proportion of resting hairs explains why the area maintains a relatively consistent density and length.
Because the hair is not actively growing for a large portion of its cycle, the overall appearance is one of stasis, where the hair seems to have reached a terminal length. The cycle repeats continuously, meaning that as one hair is shed, a new hair begins its short Anagen phase. The genetic programming of the follicle dictates this short growth period, preventing the hair from reaching the long lengths seen on the scalp.
Hormones That Dictate Pubic Hair Growth
The specific growth pattern of pubic hair is controlled primarily by androgens, such as testosterone. Pubic hair follicles are particularly sensitive to these hormones. Androgens are responsible for transforming the fine, nearly invisible vellus hair of childhood into the thicker, darker terminal hair of adulthood. This transformation, known as pubarche, occurs as androgen levels rise during puberty in both sexes.
Androgens bind to receptors within the hair follicle, which shortens the Anagen phase compared to the scalp. This hormonal influence determines the limited duration of the growth stage. The sensitivity of these follicles ensures the hair is coarser and has a fixed growth cycle, maintained throughout a person’s adult life.