Hair carries huge significance in terms of appearance and social status that extends across different cultures. However, our hair isn’t just a decorative passive appendage. In reality, hair is actually incredibly active and constantly cycling through a complex biological process of growth, rest and shedding. Even cooler, each individual hair strand has its own rhythm of growth, rest and renewal. All of these are governed by biology, hormonal and lifestyle factors. This is the hair growth cycle and is the key to understanding why your hair behaves like it does. These hair growth stages can help explain why your hair stops growing at a certain length, causes of increased shedding and thinning edges. In this guide, we’ll break down each stage of the hair growth cycle and explore what affects it. We’ll also review the best ways to support your hair at every stage of the cycle for fuller growth.
What is the Hair Growth Cycle?
The hair growth cycle is a continuous biological process through which each hair follicle grows, rests, sheds and renews itself. In humans, this cycle occurs asynchronously. This basically means that each hair follicle operates on its own timeline and is independent of the others. As such, you’ll always have hairs at different stages of the cycle at any given time. This helps maintain overall hair density. It’s also why we only shed a few hairs daily rather than all at once!
The are four main stages of the hair growth cycle consists. These are the anagen (growth), catagen (transition), telogen (rest) and exogen (shedding) phases. The duration of each stage varies depending on factors such as age, genetics, sex and overall health. It also depends where on the body the hair is. For example, the anagen phase may last 2 to 7 years for scalp hair, but is significantly shorter for body or facial hair. People with longer anagen phases can grow their hair longer before it naturally sheds, whilst those with shorter cycles may experience difficulty retaining length. Likewise, certain conditions such as hormonal imbalances, stress, or illness can disrupt the normal timing of these stages. This can lead to increased shedding or slower regrowth. Understanding how the cycle works and what influences it is vital for increasing hair growth and can help you identify early signs of disruption.
The 4 Stages of Hair Growth
Each strand of hair on your scalp goes through its own cycle of growth, rest and renewal. Whilst these hair growth stages follow a predictable sequence, the timing and balance between them can vary from person to person. Below are the four main stages of the normal hair growth cycle:
- Anagen Phase (Growth Stage): This is the longest and most active stage in the cycle in which hair grows continuously from the root. The hair follicle is fully embedded in the scalp and the supplied with oxygen and nutrients through the blood vessels. Hair cells divide rapidly, pushing the strand upward at an average rate of about 1 centimetre per month. The anagen phase typically lasts 2 to 7 years. However, this depends on factors like genetics, overall health and age. The longer this stage lasts, the longer your hair can grow.
- Catagen Phase (Transitional Stage): This phase marks the end of active growth and lasts only 2 to 3 weeks. During this transition, the hair follicle shrinks and detaches from the blood supply. This cuts off its nutrient flow. The hair stops growing but remains anchored in the follicle. Whilst only about 1% of hair is in this phase at any given time, it is a crucial reset period that prepares the follicle for renewal.
- Telogen Phase (Resting Stage): This stage typically lasts around 3 months. During telogen, the follicle remains inactive and the hair strand stays in place without growing. Roughly 10–15% of scalp hairs are in this phase at any one time. Although its a normal part of the cycle, prolonged telogen can lead to noticeable thinning or stagnant hair growth. An example of this is a hair loss condition called telogen effluvium in which stress, illness and hormonal changes can push hairs prematurely into this stage.
- Exogen Phase (Shedding Stage): The final stage, exogen is where the old hair is released from the follicle and falls out. This process often overlaps with the telogen phase and can last several weeks. Shedding 50 to 100 hairs per day is considered normal, but a noticeable increase may signal an imbalance. Factors like poor nutrition, significant stress or underlying medical conditions can increase shedding beyond typical levels. As such, this is probably the easiest and most important stage to monitor in your hair care routine.
What Can Affect the Hair Growth Cycle?
The hair growth cycle is delicately balanced and there are several internal and external factors which can interfere with it. When this balance is disrupted, more hairs than usual can enter the resting or shedding phases too soon or fail to re-enter the growth phase altogether. This can then result in hair thinning and even patches of hair loss. Below are some of the most common factors can affect the hair growth cycle:
- Hormonal Changes: Hormones like oestrogen and androgens like testosterone play a major role in regulating hair growth. Fluctuations in these hormone levels for example such as during pregnancy and menopause or due to conditions like thyroid dysfunction and polycystic ovarian syndrome (PCOS) can alter the duration of each stage in the cycle. In particular, shifts in oestrogen and progesterone can shorten the growth phase and increase shedding. This is why many people notice postpartum hair loss or thinning during menopause.
- Stress & Illness: Periods of physical or emotional stress can cause a disproportionate number of hairs to shift into the resting stage of hair growth prematurely. This leads to a type of diffuse shedding known as telogen effluvium, which typically becomes noticeable two to three months after the initial trigger. Common causes include major surgery, illness (such as COVID-19), high fevers or emotional trauma. Whilst this condition is usually temporary, it can be distressing and may take several months to stabilise.
- Nutritional Deficiencies: Hair follicles are highly active and require a steady supply of nutrients to function optimally. Deficiencies in key nutrients like iron, vitamin D, zinc, biotin and protein can disrupt hair follicle activity and slow growth.
- Ageing: As we get older, our hair naturally undergoes structural and functional changes. The growth phase tends to shorten and follicles may gradually miniaturise to produce finer, shorter and more fragile hair strands. This process is most commonly seen in age-related thinning or androgenetic alopecia (pattern hair loss).
- Drugs & Medical Conditions: A wide range of medications can affect the hair growth cycle. These include chemotherapy drugs as well as certain antidepressants, beta-blockers, anticoagulants and hormonal contraceptives. In addition, medical conditions like autoimmune diseases like alopecia areata or psoriasis, chronic infections and scalp disorders can damage follicles directly or interrupt the cycle. This can lead to patchy or generalised hair loss.
How to Care for Your Hair at Every Stage of the Growth Cycle
Despite the hair care marketing, supporting healthy hair growth isn’t just about what you apply to your strands. It starts with understanding what your follicles are doing beneath the surface. Each phase of the hair growth cycle has its own function and different follicles are at different stages at any one time. That’s why you should ensure your hair care can support each stage. Below are our top tips for how to care for your hair at every stage of the cycle:
- Anagen Phase: Focus on stimulating growth and nourishing the follicle as this is when your hair is actively growing from the root. As such this is the most critical growth stage to support if you’re aiming for longer and fuller hair. During this period, follicles rely on a steady supply of oxygen and nutrients to fuel rapid cell turnover. To make the most of this stage, stimulate the scalp regularly through massage to improve circulation and nutrient supply. Topical treatments like caffeine and minoxidil can also help prolong the anagen stage of hair growth. Techniques like microneedling and low-level laser therapy can also help activate follicle function. Nutrition is also equally important. Hair is made of keratin which is a protein so ensure your diet contains protein, iron, zinc and B vitamins to support growth even during this active phase.
- Catagen Phase: Minimise stress and protect the hair during this stage. Although it is a brief transitional phase, it’s a vulnerable period where the follicle detaches from its blood supply and growth stops. The goal here is to avoid triggering damage that could lead to premature shedding. Firstly, avoid tight hairstyles, aggressive brushing or any chemical treatments that could weaken the follicle and cause traction alopecia. Also, stick to gentle cleansing and conditioning to maintain moisture without overloading the scalp. For fine or fragile hair, consider using silk pillowcases or scarves to reduce friction and prevent breakage while you sleep.
- Telogen Phase: In this resting phase, hair is no longer growing but remains in the follicle. If too many follicles are in this phase at once, it can lead to visible thinning or slowed growth. Identify and address triggers such as lifestyle factors that can push follicles into this stage. Try to manage stress proactively as chronic emotional or physical stress is one of the most common causes of telogen effluvium. Also, review your nutritional intake and consider supplementing with iron, vitamin D, collagen or biotin if you’re deficient in any of them. Scalp treatments with ingredients like caffeine, niacinamide or rosemary oil may help stimulate blood flow and encourage follicles to re-enter the anagen phase.
- Exogen Phase: Shedding is a normal and necessary part of the hair growth cycle, but it can be unsettling if it feels excessive. During this phase, the key is to treat your hair and scalp gently and avoid compounding the loss with external damage. Try to avoid excessive heat styling, harsh detangling or frequent washing that could disturb shedding hairs. Use a wide-tooth comb and avoid brushing wet hair to minimise unnecessary breakage. You can also strengthen the hair you have with fortifying serums that contain peptides, panthenol or keratin-building ingredients.
To support the hair growth cycle at any stage, maintain a healthy scalp environment, stay hydrated, get enough sleep, eat a balanced diet and minimise harmful hair practices. Whilst some shedding and slower growth are normal, it’s important to be aware of abnormalities. Seek professional advice if you experience sudden or patchy hair loss, scalp pain, ongoing shedding lasting more than six months or noticeable thinning around the crown or temples.
Understanding the hair growth cycle can help you make informed decisions about your hair care. This is important whether you’re working to grow your hair longer, reduce shedding or simply optimise your scalp health. Try to support your hair follicles throughout all the different stages of the hair growth cycle for healthier looking strands.
We believe in a bespoke approach to hair care which is why we offer personalised hair loss and regrowth treatments through our online skin clinic. Our doctors create custom hair growth treatments using actives such as Minoxidil, Spironolactone, Melatonin, Caffeine and Tretinoin where appropriate for each and every patient. Start your virtual consultation and begin your journey to great hair today.
