Everybody loses hair every single day, though you might start to notice some areas are thinning faster than others. Depending on the area of your body and the cause of the hair loss, the amount of time it takes for hair to grow back will vary. There are a few different factors to consider, including age, genetics, hormonal changes and environmental factors.
What causes hair loss?
While hair grows all over our bodies, the area we’re typically most concerned about hair loss is on our heads. There are a variety of reasons for men and women to lose hair on their heads, including:
- Androgenetic alopecia, also known as male pattern baldness or female pattern baldness. This is the most common cause of hair loss in men.
- Alopecia areata, an autoimmune condition that causes hair to fall out suddenly and in small chunks
- Hereditary hair loss with age
- Anagen effluvium, when hairs fall out during the anagen phase of the hair growth cycle due to a toxic or inflammatory response or due to some medications like chemotherapy, radiation or severe malnutrition
- Telogen effluvium, when hairs fall out after a stressful or traumatic event
- In women, hormonal changes during pregnancy, childbirth or menopause
While all of these can cause hair loss, the most common cause of hair loss in men is androgenetic alopecia, or male pattern baldness.
What is a hair growth cycle?
Every single strand of hair on the body goes through its own hair growth cycle. This means that every hair is at its own stage of development. When it completes the cycle, it restarts and a new strand of hair begins to form.
Hair growth cycles will vary depending on where the hair is on your body. For example, hair on your scalp and head can have hair growth cycles of up to 6 years, while body hair growth cycles are only about a month. This is why body hair is significantly shorter than hair on the scalp.
What are the stages of hair growth?
All hair growth cycles include 3 stages of hair growth: anagen, catagen and telogen. The length of each stage differs per person and by location on the body.
The anagen stage of hair growth is the active growth phase. This can last anywhere between 3 to 6 years and is influenced by genetics. The longer the hair is in the anagen phase, the longer it can grow. About 90% of all hair follicles are in the anagen phase at any given time.
The catagen stage of hair growth is the transition stage that happens when the hair stops growing. This phase lasts about 4 to 6 weeks. About 1% of all hair follicles are in the catagen phase at any given time.
The telogen stage of hair growth is the resting phase when hairs fall out. An extension of the telogen stage is the exogen phase, when the hairs actually shed and fall out. This phase lasts about 2 to 3 months. About 9% of all hair follicles are in the telogen phase at any given time, which accounts for the 50 to 100 hairs that fall out every day.
Because the anagen phase lasts for years, it can seem like it will take a very long time for hair to grow back. However, there are approximately 100,000 hair follicles on your head, meaning there are about 90,000 hairs that are constantly growing.
How long does it take for hair to grow?
On average, hair grows about a centimeter each month. This means the average person will be able to grow about 12 centimeters of hair per year, though this will vary based on age and genetics.
Male pattern baldness affects 42% of all men at some stage in their lives, ranging from 16% for men 18 to 29 years old to 53% of men 40 to 49 years old. As we age, hair loss increases.
One study also found that 79% of male pattern baldness is hereditary, showing that genetics play a significant role in balding.
As we age, some follicles stop producing hair and will not grow back. This is the type of hair loss associated with androgenetic alopecia, or male pattern baldness. If you’re losing your hair due to male pattern baldness, you may be able to slow down the hair loss process with a prescription hair loss treatment called finasteride and help the hair regrowth process with a topical treatment called minoxidil.
If you want to help prevent hair loss and start regrowing your hair, you can access real hair loss treatments online through Rosemary. Our online assessments are 100% text-based and can be done anytime, anywhere. Start your online visit for prescription hair loss treatments today.
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- Clinical, cosmetic and investigational dermatology (February 2017) - Promotion of anagen, increased hair density and reduction of hair fall in a clinical setting following identification of FGF5-inhibiting compounds via a novel 2-stage process
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- Informed Health (August 2019) - What is the structure of hair and how does it grow?
- American Society for Dermatologic Surgery (December 1998) - Prevalence of male pattern hair loss in 18-49 year old men
- The Journals of Gerontology (August 2005) - Hair Loss Among Elderly Men: Etiology and Impact on Perceived Age
- American Academy of Dermatology - Do You Have Hair Loss or Hair Shedding?