This article was reviewed by Knox Beasley, MD.
Key Takeaways:
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Each hair follicle is a tiny but complex structure. From the hair bulb and dermal papilla that fuel growth to the bulge region that holds stem cells, every part of the follicle plays a unique role in producing, nourishing, and protecting each strand of hair.
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Follicles do more than grow hair. They help protect the skin, support healing through stem cells, and maintain balance by cycling through growth, rest, and renewal phases.
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Caring for your follicles supports long-term hair health. Gentle scalp care, balanced nutrition, and the right treatments can keep follicles functioning properly and help prevent hair thinning or loss.
Like the roots of the tree, the small-but-mighty hair follicle is hidden below the surface, and its health is essential for your hair to thrive. Here we’ll dive into what a hair follicle is, what it looks like, what it does, and how to keep it healthy so your hair can look its best.
What Is a Hair Follicle?
A hair follicle is a tiny tunnel-like or tubular structure that extends from the surface of the skin (epidermis) to the dermis, or the second layer of skin. Each follicle produces an individual hair strand and keeps it anchored in place.
There are about 100,000 hair follicles on the human head (which closely matches the number of hairs). However, this number varies by color.
Structure of a Hair Follicle
For such a tiny part of the human body, there are actually a surprising number of parts associated with the hair follicle. Each hair follicle has a:
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Hair Bulb: The root or the base of the hair follicle, found at its deepest part. This is where new hair cells are made, and cell division occurs.
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Matrix Cells: A layer of cells that rests on top of the dermal papilla and makes new cells. The cells in the matrix divide more rapidly than in any other organ.
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Dermal Papilla: A cone-shaped bump at the base of the bulb. It has blood vessels that bring nutrients and oxygen to the hair to help with growth
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Hair Shaft: The part of the hair you can see above the skin. It’s made of keratin.
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Hair Root: The hair within the tube of the follicle, not visible to the naked eye.
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Bulge Region: An area along the side of the follicle that holds stem cells, which help repair skin and grow new hair after injury. Stem cells in the hair follicle bulge region are activated to regenerate the lower part of the hair follicle during the anagen phase.
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Sebaceous (Oil) Gland: Connected to the follicle, this gland releases sebum to keep hair and skin moisturized.
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Arrector Pili Muscle: A tiny muscle attached to the follicle that can tighten and make your hair stand up, resulting in goosebumps.
The Hair Follicle Growth Cycle
The hair follicle grows in a predictable cycle, which is divided into four parts: the anagen (growing) phase, the catagen (regression) phase, the telogen (resting) phase, and the exogen (shedding) phase.
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The length of each phase differs. For example, research shows the catagen phase is typically just a few days long, whereas the telogen phase lasts about three months. The anagen phase can last several years.
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About 85 to 90 percent of hair follicles are in the anagen phase at any given time, and 10 to 15 percent are either resting or shedding. This is why it’s normal to see shedding every day. It’s also why all your hair does not shed at once
What Does a Hair Follicle Do?
The primary function of a hair follicle is to grow hair, which happens through a continuous cycle of growth (anagen), rest (telogen), and shedding (catagen).
During the growth phase, which is the longest phase of the cycle, cells in the hair bulb divide rapidly, pushing older cells upward, where they harden and form the visible hair shaft.
However, hair follicles do a lot more than just grow hair. Here are some other functions of the hair follicle:
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They protect the skin from environmental damage, UV radiation, and mechanical injury
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They help maintain body temperature by providing an insulating layer
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They can suppress immune response to limit inflammation
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Stem cells from hair follicles help heal wounds by moving to the skin’s surface and releasing growth factors and signals that promote cell growth and tissue repair
The Link Between Hair Follicles and Hair Loss
When hair loss occurs, it’s often indicative of damage to the follicle. Hair follicle miniaturization is the process by which hair follicles actually shrink, producing thinner, shorter, and weaker hairs, resulting in androgenetic alopecia (male pattern baldness).
This process is often caused by hormones like DHT (dihydrotestosterone), which make the growth phase shorter and the resting phase longer. Eventually, the follicles may become so small that they stop growing hair altogether.
Telogen effluvium, alopecia areata, and folliculitis are all types of hair loss related to follicles.
How to Protect and Support Your Hair Follicles
Hair health starts with healthy hair follicles. Here are some ways to help keep your hair follicles healthy.
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Wash your hair regularly. Washing your hair two to three times a week helps clear the scalp of dirt, sweat, debris, and product build-up, all of which can irritate or clog your follicles.
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Eat the rainbow. A diet rich in vitamins and minerals helps promote healthy skin and healthy hair growth.
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Avoid overly tight hairstyles. Styles that pull on the hairline, like ponytails or braids, can put stress on the hair follicles, potentially resulting in a type of hair loss known as traction alopecia.
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Massage your scalp. Research suggests that regular scalp massage can boost circulation, bringing blood and oxygen to the hair follicles. The massage also helps to exfoliate the scalp, keeping follicles free of dead skin and debris, and may promote hair growth.
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Limit heat styling: Limit your use of heat styling tools like blow dryers, straighteners, and curling irons, which can damage the hair shaft even when used properly.
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Try hair loss medications: If you’re experiencing hair loss due to hair follicle miniaturization, hair loss medications like minoxidil and finasteride can help.
Frequently Asked Questions
What is a hair follicle?
A hair follicle is a pore-like opening on the skin. It exists everywhere on the body where hair grows, including the scalp, face, arms, and legs.
Can hair follicles be regenerated?
Yes, the hair follicle naturally regenerates through the hair growth cycle (and can also do so with stem cells). However, aging, scarring, male pattern baldness, or trauma to the follicle can cause permanent damage to the follicle.
Does any part of the body not have hair follicles?
The soles of the feet, palms of the hands, and the lips do not have hair follicles.
Do hair follicles cause hair loss?
Hair follicles do not cause hair loss, per se, but a genetic sensitivity to the hormone known as DHT can cause hair follicles to shrink (a process known as hair miniaturization), which leads to hair loss.
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This article originally appeared on Hims.com and was syndicated by MediaFeed.org
