Hair Facts
The hair is an important and complex structure
At Midland Skin we offer hair consultations with a Dermatologist for patients in Birmingham, Solihull, Coventry, Wolverhampton, Worcester and the Midlands.
Interesting Facts About Hair
- The human scalp has 100,000 follicular units
- Each follicular unit has either one, two, three or four hairs growing from it. The average figure is 2-2.4
- Hair diameter and density declines with age.
- Normal hair density is 100 follicular units / cm2
- Hair loss is only appreciable once at least half the hair in a particular area is lost
- Hair follicles are constantly cycling and go through the following phases. At any one time. approximately 85% of hairs are in anagen, 2% in catagen and 13% in telogen
The Hair Cycle
Anagen – This is when the hair shaft is actively growing, usually at a rate of 0.4mm per day. This lasts 2 to 6 years. The longer anagen lasts, the longer the hair can grow.
Catagen – This is when the hair has stopped growing. The hair follicle starts shrinking. This stage lasts 2 to 3 weeks.
Telogen – This is the resting phase and lasts 3 months. The hair is not growing and is waiting to be shed. Telogen hairs are pushed out of the hair follicle when the hair follicle re-enters anagen.
About the Author
This page has been written and/or medically reviewed by Dr Sajjad Rajpar, Consultant Dermatologist and Medical Director of Midland Skin, Birmingham.
Dr Rajpar is on the GMC Specialist Register in Dermatology and has over 20 years’ experience in clinical dermatology. He provides clinical oversight to ensure the information on this page is accurate, balanced and consistent with current dermatology practice.
Dr Sajjad Rajpar
Date last updated: 28th Sep 2026
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The content on this website is provided for general information only. It is not, and must not be treated as, medical advice, a diagnosis, or a recommendation for any particular treatment. We make reasonable efforts to keep information accurate and up to date, but medicine and technology change, and content may not reflect the most current evidence, guidance, product information, or individual practice. You should not rely on this website to make decisions about your health or treatment. Always seek personalised advice from an appropriately qualified healthcare professional. Any examples, images, testimonials, and outcome descriptions are illustrative only. Results vary between individuals and no outcome can be guaranteed.
