Hair grows in a natural cycle that influences how long, thick, and strong each strand becomes. This cycle also determines how hair sheds and regrows over time.
Understanding how it works can help explain common changes—like increased shedding, slower growth, or reduced thickness—and what may be influencing them.
The hair growth cycle is a continuous process each follicle follows as it produces, sheds, and regrows hair.
Rather than growing all at once, each strand moves through its own timeline. This helps maintain overall hair coverage under normal conditions.
The cycle is influenced by:
Follicle activity
Cell turnover within the hair root
Blood and nutrient supply
Hormonal signals
During the growth phase, cells within the follicle produce keratin, the protein that forms the hair strand. This process relies on a steady supply of nutrients and oxygen.
The anagen phase is when hair is actively growing.
Typically lasts 2 to 7 years
Determines how long hair can grow
Accounts for around 85–90% of hair at any time
Hair grows steadily during this phase. A longer growth phase supports longer, thicker hair, while a shorter phase may result in finer strands.
The catagen phase is a short transition stage.
Lasts around 2 to 3 weeks
Hair growth slows
The follicle begins to shrink
This phase signals the end of active growth and prepares the hair for shedding.
In the telogen phase, the follicle rests before shedding the hair (exogen phase) and beginning a new cycle.
Lasts around 2 to 4 months
Around 10–15% of hair is in this phase
Shedding 50–150100 hairs per day is considered normal
Increased shedding may become noticeable a few months after a trigger, such as stress or illness.
The hair growth cycle isn’t synchronised—each follicle works independently. This helps maintain even hair coverage.
Under normal conditions:
Most hair remains in the growth phase
A smaller amount is shedding at any time
New hair replaces what is shed
When this balance shifts, such as more hair entering the resting phase, thinning or increased shedding can become more noticeable.
Hormones help regulate how long hair stays in the growth phase. Changes in hormone levels, such as those during perimenopause or postmenopause, can influence hair growth patterns over time.
Hair follicles rely on a steady supply of nutrients to support normal growth. When intake is low, growth may slow and more hair may shift into the resting phase.
Key nutrients include iron, protein, and zinc, which play roles in normal hair structure and function.
Stress can affect the hair growth cycle by shifting more hair into the resting phase. This may lead to increased shedding several weeks to a few months later.
As part of the natural ageing process:
The growth phase may become shorter
Hair may grow more slowly
Strands may become finer
Over time, this can affect overall hair density.
When the cycle becomes unbalanced, visible changes in hair can occur.
This may include:
A shorter growth phase, leading to shorter or finer strands
More hair entering the shedding phase at once
Gradual thinning of individual strands over time
These changes can contribute to reduced density and slower regrowth.
A balanced diet provides the nutrients needed for normal hair growth. Including protein-rich foods, leafy greens, nuts, seeds, and whole grains can help support hair health.
Managing stress, getting enough sleep, and supporting overall wellbeing can help maintain normal body processes, including hair growth.
Gentle hair care and a healthy scalp environment can also help reduce unnecessary strain on hair.
During certain life stages, nutritional needs may increase. Supplements may help support general nutritional intake where dietary intake is inadequate.
Formulations designed for hair health often include nutrients such as biotin and zinc, which help maintain normal hair structure and condition.
Understanding the hair growth cycle can help make sense of changes like thinning or increased shedding.
It can also provide insight into:
How long hair takes to grow
Why changes may be temporary or ongoing
What factors may influence hair health
This knowledge can help you better understand your hair and support it over time.
The full cycle varies for each follicle. The growth phase can last several years, while the shedding phase occurs over a few months.
Yes. Shedding around 50 to 150100 hairs daily is a normal part of the hair growth cycle.
Supporting overall health through balanced nutrition, stress management, and gentle hair care can help maintain normal hair growth processes.
Hair may appear to stop growing when the growth phase becomes shorter or when more hair enters the resting phase.
