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Understanding Hair Loss and hair growth cycles

Updated: Apr 29

Hair loss, known medically as alopecia, encompasses a spectrum of conditions that can affect anyone, regardless of age, gender, or hair type. Whether it's localized or widespread, temporary or permanent, hair loss can have a significant impact on self-esteem and overall well-being.

Who's Affected by Hair Loss?

From males to females, children to adults, and individuals with varying hair colors and textures, hair loss doesn't discriminate. It can occur in isolation or be linked to underlying medical conditions, making it crucial to understand its causes and potential treatments.

The Hair Growth Cycle

To grasp the complexities of hair loss, it's essential to understand how hair grows. Hair follicles undergo a continuous cycle of growth, transition, and rest, with each strand following its unique timeline. Factors such as genetics, hormones, and environmental influences can influence this cycle, impacting the thickness and length of hair. A hair shaft grows within a follicle at a rate of about 1 cm per month. It is due to cell division within the hair bulb at the base of the follicle. The cells produce the three layers of the hair shaft (medulla, cortex, cuticle), which are mainly made of the protein keratin (which is also the main structure of skin and nails).

Hair growth follows a cycle. However, these phases are not synchronised, and any hair may be at a particular phase at random.

The three main phases of the hair cycle are:

  1. Anagen: actively growing hair, most of them

  2. Catagen: in-between phase of 2–3 weeks when growth stops and the follicle shrinks, 1–3% of hairs

  3. Telogen: resting phase for 1–4 months, up to 10% of hairs in a normal scalp.

Hair length depends on the duration of anagen. Short hairs (eyelashes, eyebrows, hair on arms and legs) have a short anagen phase of around one month. Anagen lasts up to 6 years or longer in scalp hair.

Pictures and excerpts and links Courtesy of Dermnet.NZ

Anagen hair loss

Anagen hair is tapered or broken-off. Anagen is variable in duration. Children with otherwise normal hair but that cannot grow their hair long may have short anagen syndrome.

Anagen shedding is known as anagen effluvium and has a sudden onset.

Anagen effluvium is caused by:

Short broken hairs and empty follicles may be observed. If caused by a drug or toxin, hair growth can return to normal within 3–6 months of its withdrawal.

Telogen hair loss

Telogen hair has a bulb at the end (club hair). Excessive shedding is known as telogen effluvium. It occurs 2–6 months after an event that stops active hair growth.

Telogen effluvium is caused by:

Sometimes there appears to be no recognisable cause for telogen effluvium, and shedding can continue for years (chronic telogen effluvium). Scalp hair continues to grow but has a shorter natural length than normal.

What Triggers Hair Loss?

Hair loss can stem from various factors, including decreased growth, increased shedding, or changes in hair structure. Autoimmune diseases, medications, hormonal imbalances, and congenital abnormalities are just a few potential culprits. Understanding the underlying cause is key to determining the most effective treatment approach.

Identifying Hair Loss: Signs and Symptoms

While hair loss itself may not always be accompanied by noticeable symptoms, underlying conditions or inflammatory skin diseases may manifest with itchiness or discomfort. Understanding these signs can aid in early detection and prompt treatment initiation.

Treatment Options for Hair Loss

Treatment for hair loss depends on the underlying cause. Whether it's addressing infections, deficiencies, or inflammatory conditions, a tailored approach is essential for optimal outcomes. Additionally, lifestyle modifications, such as minimizing chemical treatments and adopting loose hairstyles, can help prevent further damage.

The Outlook for Hair Loss

The prognosis for hair loss varies based on the diagnosis. While some conditions may resolve with time or treatment, others may result in permanent baldness. However, early intervention, coupled with advances in medical technology, offers hope for improved outcomes and enhanced quality of life.


Hair loss is a multifaceted issue that requires a comprehensive understanding of its causes, symptoms, and treatment options. By recognizing the signs early and seeking appropriate medical guidance, individuals can take proactive steps towards managing hair loss and maintaining healthy hair and scalp. Remember, you're not alone in this journey, and there are resources and support available to help you navigate through it.

Dr Purity Carr

GP a& Menopause Doctor

Harvey WA, 6220

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