The 4 Stages of Hair Growth

Each hair strand grows out of its own tiny pocket in the skin called a hair follicle, and every follicle runs on its own internal clock. This means your hairs are never perfectly in sync, some are growing while others are resting or shedding. That’s why you don’t lose all your hair at once, even if thinning occurs.

The hair growth cycle is usually described in four main stages, or phases of hair growth:

1. Anagen (growth phase)
2. Catagen (transition phase)
3. Telogen (resting phase)
4. Exogen (shedding phase)

Many people have heard of three stages, but exogen is now recognised as its own phase, even though it overlaps with telogen. Understanding these stages helps explain why hair length, thickness, and shedding vary between people and over time.

1. Anagen (growth phase)

The anagen phase is where all the action happens. Around 85–90% of scalp hair sits in this stage at any time. Inside the follicle, keratinocyte cells are rapidly divided, drawing nutrients from the surrounding blood vessels to build the hair shaft.

This phase has two parts: one where cells are working at full speed to form the strand, and one where the hair breaks the surface. This longest phase of hair growth is when most hair is growing, which is why scalp hair can reach considerable lengths.

Scalp hair stays in anagen for roughly 2–8 years, which is why it can grow long. Body hair, lashes and eyebrows have a much shorter anagen phase, which is why they never reach the same length.

2. Catagen (transition phase)

Catagen is the short transition between growth and rest. Only 1–2% of scalp hairs are in this stage, and it lasts about 1 to 2 weeks.

The follicle shrinks, the lower part breaks down, and growth stops. The hair detaches from its blood supply and becomes what is known as a club hair. It is fully formed but still anchored, so you usually do not notice this phase at all.

By the end, the follicle is preparing to enter telogen.

3. Telogen (resting phase)

Telogen is the quiet part of the cycle, best described as the “resting phase” of the hair growth cycle lasting for around 3 months. The follicle rests, the strand stays put, and no active growth happens. Roughly 10–15% of scalp hairs of scalp hairs sit in this stage at any time.

Some telogen hairs shed during everyday activities, while others stay anchored until exogen properly begins. Telogen always overlaps with early exogen, which is why shedding can feel unpredictable.

4. Exogen (shedding phase)

Exogen is the part people panic about, even though it is completely normal. During this stage the old club hair loosens and sheds, making space for the new hair developing deeper in the follicle.

Shedding around 50–100 hairs a day is simply part of exogen. Issues occur when more hairs than usual are pushed into shedding, or fewer new hairs re-enter the growth phase.

What Influences The Hair Growth Cycle?

Your hair mostly grows on its own, but plenty of things- both inside and outside your body – can speed up, slow down, or disrupt each stage. When these factors shorten the growth phase or push more hairs into resting or shedding, you may notice slower growth, reduced density or more noticeable thinning.​

A few key influences include:

• Genetics: Determine growth phase length, speed and likelihood of pattern hair loss.
• Hormonal changes: Hormones such as androgens and oestrogen directly affect follicles. Which is why conditions like pregnancy, polycystic ovary syndrome (PCOS), and menopause can change how hair is growing.​
• Stress: Physical or emotional stress can temporarily disrupt the cycle and trigger telogen effluvium, where more hairs move into the telogen stage at once before shedding.​
• Nutritional deficiencies: Low iron, vitamin D, and certain B vitamins can disrupt hair follicle functions, impacting growth and overall hair health.
• Ageing: As we age, the growth phase of hair often shortens and more follicles spend time in resting phases, which can gradually reduce hair thickness and density.​
• Health and lifestyle: Medical conditions, some medications, smoking, excessive alcohol, and poor scalp health (including inflammation) can all contribute to causing hair thinning or increased shedding.​​

How disruptions in the growth cycle lead to hair loss

When the hair growth cycle is balanced, shedding and regrowth stay in step and overall hair density remains stable. Hair loss becomes noticeable when that balance shifts: if fewer hairs enter or stay in the growth phase, or more hairs move into the shedding phase at once, you may see diffuse thinning, widening parts, or classic pattern baldness.​

Some common hair loss conditions linked to changes in the hair growth cycle include:

• Male pattern baldness (androgenetic alopecia): A common condition where genetics and hormones cause  the hair follicles on the scalp to shrink over time, shortening the growth phase and producing finer hair until follicles stop producing visible hair.​ 
• Female pattern hair loss: Similar to male pattern baldness but with different patterns of thinning, often showing as diffuse thinning over the crown rather than a receding hairline.​
• Telogen effluvium: A temporary condition where a larger number of hairs enter the telogen and exogen shedding phases after a trigger such as illness, surgery, major stress, or rapid weight loss, causing diffuse shedding across the scalp.​
• Alopecia areata: An autoimmune condition in which the immune system attacks hair follicles, disrupting normal follicle function and causing patchy hair loss.​

The good news is that many of these related conditions are manageable, especially when detected early, and there are clinically backed hair loss medications and treatments designed to support a healthier balance between hair growth and shedding.

How To Maintain Hair Health During Each Stage

Supporting healthy hair growth is about giving your follicles the best possible environment through every stage of the cycle. While not every cause of hair loss can be fully prevented, consistent habits and proven treatments can help protect hair strands, promote a stronger growing phase, and reduce unnecessary damage or shedding.​

Practical ways to support healthy hair during each stage include:

1. Use hair-strengthening products: Gentle shampoos, conditioners, and leave-ins free from harsh sulphates or alcohol.
2. Maintain a healthy diet: Protein, iron, zinc, and vitamins support follicles; supplements if needed.
3. Reduce stress: Exercise, sleep, mindfulness, or therapy reduce telogen effluvium risk. 
4. Avoid over-styling: Limit heat, tight hairstyles, and harsh chemicals.
5. Protect from sun damage: Hats or UV-protective products prevent weakening.
6. Use medically reviewed treatments prescribed by a healthcare professional where appropriate.

A Hair Loss Treatment Made for You

If you suspect that your hair growth cycle has been disrupted, you’re not alone and it’s not something you have to simply accept. Many people naturally see their growth phase shorten with age, but early treatment can help slow, stop, or even partially reverse hair loss in some cases.​

The Hairy Pill provides a personalised, once-daily treatment for men’s and women’s hair loss, built on technology developed by world-renowned dermatologist Professor Rodney Sinclair and validated in clinical settings. After you sign up and complete a short medical form, a doctor reviews your details and a pharmacist calls to confirm your treatment. It is then compounded and delivered to your door, giving you an easier and more structured way to support healthy hair growth without the trial and error.

FAQs

How long is a hair growth cycle for hair?

A full scalp hair growth cycle lasts several years. The anagen phase alone is 2–8 years, followed by shorter transition, resting, and shedding phases. Timing varies by genetics, age, and health.

How do I restart my hair growth cycle?

You can’t fully restart it, but supporting follicles to stay longer in the growth phase helps. Healthy habits and proven treatments, like The Hairy Pill, can target thinning.

How can I tell if my hair is in the anagen phase?

Anagen hair is actively growing, feels firmly anchored, and makes up most visible hair. Telogen hairs shed easily.

Is shedding 100 hairs a day normal?

Yes. Shedding 50–100 hairs daily is normal. Excessive shedding over weeks may need a doctor’s check for conditions like telogen effluvium.

Do hair transplants change the hair growth cycle?

Transplanted follicles follow their own normal hair growth cycle once healed after hair transplantation. Ongoing treatments may still be recommended to protect existing hair and maintain overall density.