What is a Hair Follicle:
All You Need to Know

• 30 June 2025
• Dr. Ossman Ashraf

Last updated on June 30, 2025

Hair is more than just what we see on the surface—every strand begins its life inside a tiny structure called a hair follicle. These microscopic pockets in the skin are where all hair growth originates, making them central to understanding hair health, growth, and even hair loss. Whether you’re experiencing thinning hair or are simply curious about how hair grows, our hair loss team will walk you through everything you need to know about hair follicles.

Understanding Hair Follicle Structure and Function

A hair follicle is a tunnel-like structure in the outer layer of your skin (epidermis) that extends deep into the dermis. Each follicle anchors a single strand of hair into the scalp or skin and plays a vital role in the growth, texture, and thickness of your hair.

At the base of the follicle is the hair bulb, where living cells divide and grow to build the hair shaft. These cells are nourished by blood vessels in the dermal papilla, delivering oxygen and nutrients to sustain the growth cycle.

What is the Structure of the Hair Follicle?

To understand how hair grows, it’s helpful to know the different parts of the hair follicle structure:

• Hair Bulb: The rounded, root-like base of the follicle. This is where active cell division occurs.
• Dermal Papilla: Located at the base of the bulb, this contains capillaries and nerves essential for hair growth.
• Matrix Cells: These divide rapidly to form the hair shaft and the inner root sheath.
• Sebaceous Gland: Connected to the follicle, this gland produces sebum (natural oil) to lubricate hair and scalp.
• Arrector Pili Muscle: A tiny muscle that causes hair to stand up when it contracts, often referred to as “goosebumps.”

The Hair Follicle Growth Cycle

Hair follicles cycle through four main phases, each playing a role in the growth and shedding of hair:

1. Anagen (Growth Phase)

This is the active growth phase, lasting 2–7 years depending on genetics and health. About 85–90% of the hair on your head is in this phase at any given time.

2. Catagen (Transition Phase)

Lasting around 2–3 weeks, this short phase marks the end of active growth. The hair follicle shrinks, and the lower part is reabsorbed.

3. Telogen (Resting Phase)

The follicle remains dormant for about 3 months. Roughly 10–15% of hairs are in this phase.

4. Exogen (Shedding Phase)

During this phase, the old hair is shed, and the follicle returns to anagen to begin producing new hair.

Disruptions to this cycle—such as stress, illness, hormonal changes, or certain medications—can lead to excessive shedding or thinning.

Why Hair Follicles Are Important

Healthy follicles are essential for hair density, thickness, and strength. When follicles are damaged or inflamed, they can shrink (a process called miniaturisation), produce weaker hair, or stop growing hair altogether. This is often seen in conditions like androgenetic alopecia (pattern baldness) or alopecia areata.

Follicle health can also influence:

• Texture: Straight, wavy, or curly hair depends on the shape of the follicle.
• Growth Rate: A well-nourished follicle grows hair more quickly.
• Pigment: Melanin is produced in the follicle to colour the hair strand.

Factors That Affect Hair Follicle Health

Several internal and external factors influence the health of your scalp and condition of your hair follicles:

• Hormonal Imbalance: Androgens like DHT can shrink follicles, especially in genetically sensitive individuals.
• Nutrition: Follicles require protein, iron, vitamins A, D, E, biotin and B-complex vitamins to function well.
• Scalp Health: Inflammation, dandruff, or poor circulation can impair follicle performance.
• Stress: Chronic stress can disrupt the hair growth cycle, pushing follicles into the resting phase too early.
• Hairstyling Practices: Overuse of heat tools, tight hairstyles, and chemical treatments can damage follicles over time.

Can Hair Follicles Be Regenerated?

While severely damaged or scarred follicles (such as from burns or scarring alopecia) often can’t regrow hair, many follicles that are dormant or weakened can be revived with the right medical support. Treatments that stimulate blood flow, reduce inflammation, or block DHT can improve follicle health and restore growth in many cases.

Options like Plasma Growth Factor Treatment, exosome therapy, mesotherapy, or targeted medications may help reawaken dormant follicles and support healthy regrowth.

How to Protect and Support Your Hair Follicles

Maintaining healthy hair follicles is key to preventing thinning and supporting thick, strong hair. Here are a few practical tips:

• Use gentle hair care products: Sulphate-free, paraben-free shampoos can help maintain scalp health without irritating follicles.
• Avoid tight hairstyles: Styles that pull on the hairline, like ponytails or braids, can cause follicle stress and traction alopecia.
• Massage your scalp: Regular scalp massage can boost circulation and support follicle nourishment.
• Eat a balanced diet: Include protein, healthy fats, iron, and hair-supportive vitamins in your meals.
• Limit heat styling: Give your follicles a break from blow dryers, straighteners, and curling irons.

We support hair follicle health and hair growth with advanced, doctor-led treatments tailored to your needs—helping you restore stronger, thicker hair naturally.

Expert Diagnosis and Advanced Hair Loss Treatments at Hair Doctors

At Hair Doctors, we offer in-depth scalp and hair follicle analysis using the latest artificial intelligence-driven technology—HairMetrix. This allows us to assess your scalp health, hair density, follicle function, and track your hair growth progress with unmatched accuracy.

Our doctor-led team specialises in diagnosing all forms of hair loss and creating personalised, evidence-based treatment plans tailored to your stage of hair loss. From early intervention options like the Hair Growth Protocol, Exosome treatment and growth factor treatment to advanced solutions like Micro FUE and DHI hair transplants, we provide treatments that support follicle health and restore natural-looking hair growth.

With discreet, doctor-led clinics in Sydney, Melbourne, and Parramatta, you’ll receive expert care in a luxurious and supportive environment. If you’re concerned about hair thinning or want to give your follicles the best possible future, contact us today for a confidential consultation.

FAQs

What is a hair follicle and what does it do?

A hair follicle is a tiny pocket in the skin that anchors each strand of hair. It houses the hair bulb, where new cells grow to form the hair shaft. Follicles also contain sebaceous glands and blood vessels that nourish and lubricate the hair. At Hair Doctors, we assess follicle health using advanced technology in our Sydney, Melbourne, and Parramatta clinics. Book a consultation to explore tailored hair loss treatments.

How do hair follicles grow hair?

Hair growth starts in the follicle’s bulb, where active cell division creates the hair strand. These cells are pushed up and hardened into keratin as the hair grows. The follicle’s growth cycle—anagen, catagen, telogen, and exogen—determines how long hair grows. If you’re experiencing thinning, Hair Doctors offers personalised treatment plans backed by medical science. Visit one of our doctor-led clinics for a full scalp and hair growth analysis.

Can damaged hair follicles be repaired?

Mildly damaged or dormant follicles can often be revived with professional care, depending on the cause. Hair growth treatments like Plasma Growth Factor Therapy, mesotherapy, or our exclusive Hair Growth Protocol can support follicle recovery. However, scarred or destroyed follicles may not regrow hair. At Hair Doctors, we’ll assess your follicles with the HairMetrix analyser and recommend the most effective option—available at our Sydney, Melbourne, and Parramatta clinics.

What causes hair follicles to stop working?

Follicles may stop producing hair due to hormonal changes (like DHT sensitivity), autoimmune conditions, poor scalp health, nutritional deficiencies, or stress. In some cases, the follicle shrinks (miniaturises), producing finer, weaker hair. At Hair Doctors, our expert team investigates the cause and delivers evidence-based treatments to restore function where possible. Book a consultation at one of our discreet clinics to protect your follicles.

How do I know if my hair follicles are healthy?

Healthy follicles produce thick, strong hair and follow a normal growth cycle. Signs of trouble include thinning strands, slower growth, or patchy hair loss. The best way to assess follicle health is through a detailed scalp and hair analysis. At Hair Doctors, we use AI-powered HairMetrix technology to evaluate your follicles and track progress over time. Book online and visit our Sydney, Melbourne, or Parramatta clinics for an expert diagnosis and a tailored hair loss treatment plan.