Humans possess hair follicles covering their entire bodies. There are two primary types of hair follicles: vellus hair follicles and terminal hair follicles. Throughout their lifespan, individuals undergo transitions from vellus to terminal hair, as well as the transformation of terminal hair into vellus hair. Explore the details about these two types of hair, understanding their similarities and distinctions.
| Fun Fact: The average human has approximately 5 million hair follicles, with the density of hair follicles varying across different body regions. |
What is Vellus Hair?
Vellus hair is the fine, short and nearly invisible hair that blankets the body. The thickness, length and color of vellus hair may differ among individuals, but they are typically inconspicuous due to the absence of pigment. Commonly known by colloquial terms such as ‘baby hair’ or ‘peach fuzz’, vellus hair is present across various body areas, including the face, arms, neck, legs and torso. Notably, they do not grow on the hand’s palms, feet’s soles, upper lips and eyelids.
What is Terminal Hair?
Terminal hair is coarse and thick, like the hair found on the scalp. It is prominently visible on areas such as the eyelashes, eyebrows, beard, armpits and the pubic region. Distinctive terminal hair is also common on the arms, belly, legs, back and chest. Notably, approximately 90% of men’s bodies are covered with terminal hair.
Vellus Hair Vs Terminal Hair: Similarities
Here are some similarities between the two major types of hair:
- Both types of hair emerge after birth and can appear on the body simultaneously.
- They are present in various body areas except for the lips, the palm of the hand, the navel, the back of the ear, some external genital areas, the sole of the foot and scar tissue.
- The shaft of both types of hair is composed of keratin, with the living portion being the hair follicle that gives rise to the hair shaft.
- Melanocytes are present in the bulb of both types of hair.
- Both types of hair contribute to body protection by supporting thermoregulation, aiding the human body in regulating temperature in hot and cold environments.
Vellus Hair Vs Terminal Hair: Differences
Vellus hair and terminal hair can grow alongside each other, contributing to body protection through thermoregulation, but they have fundamental differences. Here are the key distinctions between the two types of hair.
- Vellus hair is characterized by its short, thin and faintly colored appearance, making it barely noticeable. In contrast, terminal hair is long, thick and dark.
- Terminal hair is situated deeper in the skin compared to vellus hair.
- Terminal hair exhibits faster growth than vellus hair, with a rate of approximately 1 cm (0.4 inches) per month.
- The shaft of vellus hair lacks a medulla, whereas the shaft of terminal hair contains a medulla.
- Vellus hair can reach a length of up to 2 mm, while terminal hair can grow up to 3 feet long.
- Androgens do not influence the development of vellus hair, whereas they play a crucial role in transforming vellus hair into terminal hair.
Transition Between Types of Hair
The changes in your hair during puberty are influenced by hormones affecting vellus hair. Androgens, a type of sex hormone, play a role in transforming vellus hair into terminal hair. This hormonal shift leads to the development of dark, coarse hair in regions such as the armpits, on the face and around the genitals. It’s common to observe an increase in darker, longer and thicker hair across the chest, upper back, arms, hands, legs and feet.
As you age, vellus hair often diminishes, either falling out or becoming shorter. However, some individuals may experience an upsurge in vellus hair, accompanied by a reduction in terminal hair on the scalp. This phenomenon, known as miniaturization, is often associated with androgenic alopecia, or pattern hair loss. Similar to the gradual transformation of vellus hair into terminal hair during puberty, the shift from terminal hair to vellus hair in androgenic alopecia occurs gradually. It becomes more noticeable when distinct symptoms of pattern hair loss, such as changes to the hairline and loss around the temples and crown of the head, become apparent.
| Pro Tip: To stimulate hair growth and maintain hair health, consider massaging your scalp regularly. Scalp massage helps improve blood circulation, which, in turn, promotes better nutrient delivery to hair follicles and encourages overall hair vitality. |
Conclusion
The two major types of hair covering the human body are vellus hair and terminal hair. Vellus hair is short, thin, and faintly colored, often making it barely noticeable. In contrast, terminal hair is characterized by its long, thick, and dark appearance. Over their lifetime, people often experience a transition between the two types, particularly during puberty and old age.
