Research confirms that the blood vessels supplying beard growth are more abundant than those at hair roots, facilitating easier nutrient delivery. Combined with androgen stimulation, beards grow faster than hair—averaging about 0.40 mm daily (compared to 0.27–0.40 mm for hair). Moreover, stronger male reproductive function correlates with faster beard growth.
Of course, beard growth is also influenced by follicular receptors: the more receptors present, the denser the beard. Due to these receptors, men with equally high androgen levels exhibit vastly different beard patterns—those with more receptors grow thicker beards, while those with fewer develop sparser ones.
Due to genetic factors, everyone's facial hair is unique. Some grow full beards like Li Kui, others have sparse patches like Yan Qing, some sport a long beard like Guan Yu, and others have a thin line like Sun Quan.However, no matter how peculiar your beard may be, when it ceases to grow as vigorously as before and suddenly becomes sparse or even falls out, your sexual function will also decline in tandem with the reduction in beard density.
Beard growth follows natural patterns. It typically begins during adolescence as soft, downy hair. After puberty, men's facial hair generally grows faster than scalp hair due to the influence of androgens. By adulthood, beard color usually matches hair color, and the texture hardens—a phase coinciding with sexual function stabilizing.
After adulthood, excessive beard growth generally occurs in two scenarios. One involves excessive androgen secretion, such as from adrenal tumors, where overstimulation by androgens causes uncontrolled growth. The other arises from excessive intake of androgens or androgenic products, leading to hyperandrogenism and similarly excessive beard growth.