Hair Biology
6 entriesHow hair is built, how it grows and why it changes colour.
View all 6 entries →Hair Library · The Hair Encyclopedia
Everything About Hair. Backed by Science.
Reference entries on hair biology, hair loss, scalp health, treatments, hair care and hair transplantation. Written from published research, linked to PubMed and medically reviewed.
Reading level
Start Here
Three reading paths through the encyclopedia. Start with the one that fits you.
Understanding your hair loss
For patients: the essentials, in plain words.
Clinical reference
For professionals: biology, evidence and complications.
Caring for your hair
For everyone: hair types, products and what the evidence says.
Browse by Category
From the biology of a single follicle to hair care, treatments and hair transplantation.
Hair Types & Texture
7 entriesFrom 1A straight to 4C coily, porosity and curl patterns.
View all 7 entries →Hair Loss
12 entriesPatterns, causes and stages of hair loss, including hair loss linked to hormones and medicines.
View all 12 entries →Scalp Conditions
4 entriesPain, bumps, pimples and infections of the scalp, and when to see a doctor.
View all 4 entries →Hair Loss Treatments
6 entriesWhat the research says about medicines and therapies for hair loss.
View all 6 entries →Hair Care & Ingredients
9 entriesOils, shampoos, serums, supplements and the ingredients inside them.
View all 9 entries →Hair Transplantation
28 entriesEvery technique, how grafts are planned, recovery and safety.
Techniques & Procedure 12
Grafts & Planning 6
Recovery & Aftercare 7
Complications & Safety 2
History & Records 1
A category opens once it has at least three entries. Next: Hair Genetics · Hair Technology · Hair Regeneration.
Questions People Ask About Hair
Each question has a full, referenced answer in the library.
How fast does hair grow?Hair BiologyHow many hairs are on the human head?Hair BiologyWhat causes gray hair?Hair BiologyDo eyebrows grow back?Hair BiologyIs a mature hairline normal or receding?Hair LossCan birth control cause hair loss?Hair LossDoes red light therapy work for hair loss?Hair Loss TreatmentsDoes hair growth serum work?Hair Care & IngredientsHow many grafts do I need?Hair TransplantationCan a hair transplant change hair texture?Hair TransplantationCan I go to work after a hair transplant?Hair TransplantationHow long do hair transplants last?Hair Transplantation
Glossary: Hair Terms Explained
Every term answered in a few sentences, with a link to the full entry when there is more to know.
What is the dermal papilla?
The dermal papilla is a cluster of cells at the centre of the hair bulb. It signals the bulb and helps decide how thick, how long and what colour each hair grows.
Full entry: Hair Bulb Anatomy →What is a graft?
A graft is a follicular unit taken from the donor area and placed in the thinning area. It holds one to four hairs, rarely more, so 2,000 grafts is roughly 3,600 to 4,600 hairs.
Full entry: How Many Grafts Do I Need? →What is shock loss?
Shock loss is a temporary shedding phase after a hair transplant, triggered by surgical stress to the scalp and typically starting 2 to 4 weeks after the procedure. The follicles remain healthy beneath the skin, and new growth resumes within 4 to 6 months.
Full entry: Shock Loss →What is the Norwood scale?
The Norwood scale is the classification most doctors use for male pattern hair loss. It describes the usual ways the loss moves, stage by stage, from Norwood 1 to Norwood 7.
Full entry: Norwood Scale: Stages 1–7 →Interactive Tools
Find your stage, your hair type and a typical graft range.
Research Digest
New studies, summarized in plain language, with a link to the original paper. Each summary is medically reviewed.
Complications in follicular unit excision hair transplantation: current evidence and practical approaches
Lists complete follicular unit extraction and avoiding transection, cutting through the follicle, as key preventive measures in FUE.
Romera de Blas C, Vega Díez D, Ricart Vayá JM, Gómez Zubiaur A · Cited in: Hair Bulb Anatomy
Dermal Papilla Cells: From Basic Research to Translational Applications
Describes the main parts of the hair bulb and states that the dermal papilla controls the growth, shape, size and colour of hair.
Zhang HL, Qiu XX, Liao XH · Cited in: Hair Bulb Anatomy
SourcesNumbered in every entry, linked to PubMed, with study type and published corrections shown.
Medical reviewEach entry is reviewed and dated.
Revision historyEvery change is recorded.
Sources & copyrightHow we use sources · Corrections · Editorial policy
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