Pubic hair often seems to grow back remarkably fast after trimming or removal. This perceived speed is not because the hair grows significantly faster than hair elsewhere on the body. Instead, it is due to fundamental biological differences in the lifespan and cyclical pattern of the hair follicle in that region. The quick return to a noticeable length results from a short maximum growth period combined with the hair’s inherent thickness.
Understanding the Hair Growth Cycle
All hair on the human body follows a predictable, recurring pattern known as the hair growth cycle. This cycle is divided into three phases: Anagen, Catagen, and Telogen. The Anagen phase is the active period of growth where cells in the hair root divide rapidly, adding to the hair shaft.
The Catagen phase is a brief, transitional stage that signals the end of active growth. During this time, the hair follicle shrinks and detaches from its nourishing blood supply, typically lasting only a couple of weeks for most body hair. The final stage is the Telogen phase, a resting period where the hair remains in the follicle but does not grow. After this phase, the old hair is shed, and the follicle begins a new Anagen cycle. The duration of these phases varies dramatically across the body, which determines the maximum length a hair can achieve.
The Speed of Growth During Anagen
The daily rate at which pubic hair grows during its active phase is comparable to that of scalp hair. Hair in the Anagen phase grows approximately 0.3 to 0.4 millimeters per day, regardless of its location on the body. The illusion of rapid growth after a trim is due to its unique cycle timing, not an increased growth speed.
The key difference is the duration of the Anagen phase, which dictates the hair’s potential maximum length. Scalp hair follicles can remain in the Anagen phase for two to eight years, allowing the hair to grow very long. In contrast, pubic hair follicles have a significantly shorter Anagen phase, typically lasting only a few weeks to a few months, often ranging from 30 days to four months.
Because the growing phase is short, the hair quickly reaches its genetically determined limit before entering the resting and shedding phases. Trimming or shaving pubic hair simply resets this short Anagen phase, causing the hair to rapidly grow back to its maximum length before growth stops again. Furthermore, up to 70% of pubic hair is in the Telogen (resting) phase at any given time, meaning only a fraction is actively growing.
Hormones That Determine Hair Type and Location
The specific type of hair found in the pubic region is categorized as terminal hair. This hair is thicker, coarser, and darker than the fine, almost invisible vellus hair that covers most of the body before puberty. This transformation from vellus to terminal hair is controlled by the body’s sensitivity to androgen hormones.
Androgens, such as testosterone and dihydrotestosterone, increase significantly during puberty in both males and females. Hair follicles in the pubic and armpit regions are highly sensitive to these circulating hormones. The presence of androgens stimulates these specialized follicles to produce the coarse, dense hair characteristic of the area.
This hormonal programming explains why this specific type of hair grows in a defined location and feels different from the hair on your arms or legs. The androgen-stimulated follicle produces a hair shaft that is thicker and more heavily pigmented. This thickness contributes to the perception that the hair is growing back quickly immediately after being cut.