This list contains some familiar and not so familiar specialised terms on hair loss, structure and function.  The descriptions are designed to give you a basic understanding of the components of hair. Enjoy!


This generally describes the visible thinning of hair.

Alopecia areata (Spot baldness)

A health problem that causes bald spots or patches on the scalp also known as localised pathogenic hair loss.

Alopecia Totalis

Is a term for hairloss which occurs over the entire scalp.

Alopecia Universalis

Is a term for hairloss which occurs over the entire body.

Amino acids

These are the building blocks of proteins in living organisms.

Anagen phase

The active growth phase of hair follicles. Up to 90% of head hair are in this phase producing 1 cm of growth every 28 days.


Androgens are often referred to as male hormones.


An antiandrogen blocks the effects of androgens, normally by blocking the receptor sites.

Azelaic Acid

Azelaic acid like Retin-A is more commonly used in the treatment of acne and other skin conditions. However, it has also been used as a potential treatment of androgenetic alopecia.

Androgenic alopecia (Male pattern Baldness)

The most common cause of hair loss in both men and women.


A water-soluble B-complex vitamin also known as vitamin B7 or vitamin H. It has an important function in cell growth by the metabolism of fatty acids.

Catagen phase

Is the resting phase of the hair cycle also known as the transitional phase, in which the follicle is no longer producing hair grow.


The cortex is the main structure of the hairshaft. The cortex determines the colour and texture of the hair.

Cyproterone Acetate

The drug is normally used to reduce the excessive sex drive in men. It is also prescribed to treat hirsuitism and androgenetic alopecia in women.

Dermal papilla

The dermal papilla is situated at the base of the hair follicle. It contains nerves and blood vessels which supply glucose for energy and amino acids to make keratin.

Diffuse hair loss

The hair density decreases evenly all over the head.

Dihydrotestosterone (DHT)

A male sex hormone that is the primary contributing factor in male pattern baldness. DHT is formed when the male hormone testosterone interacts with the enzyme 5-alpha reductase.

Exogen phase

An independent shedding phase of the hair cycle which occurs separate from anagen and telogen. One of several hairs may arise from a single follicle.

Hair cycle

Consists of three distinct and concurrent phases:
1) Anagen, the growth phase, 2–7 years.
2) Catagen, the regressing phase, 2–3 weeks.
3) Telogen, the rest phase, 5-6 weeks.

Hair follicle

A skin organ that produces hair within a layer of dermis. It is attached to the sebaceous gland.

Hair loss

This is a normal phenomenon in the hair cycle. It is pathogenic only if 80-100 hairs are lost daily on a permanent basis.

Hair papilla

The hair papilla lies under the dermis and builds the hair and is therefore more or less the foundation of the hair.

Hair shaft

The hair shaft is formed when the keratin stem cells within the follicle grow above the skin surface.

Hereditary hair loss (Androgenic hair loss)

Also androgenic hair loss. Hereditary hypersensitivity to the hormone dihydrotestosterone. Hair loss brought about by this is most commonly thought to be genetic.


Is a kind protein that is present in hair and nails.


The medulla is a central zone of cells present only in large thick hairs.


This is a non-prescription medication approved for androgenetic alopecia and alopecia areata. Minoxidil comes in a liquid or foam that is rubbed into your scalp twice a day. This is the most effective method to treat male-pattern and female-pattern hair loss.


Basic non-proteinogenic amino acid. Helps strengthen the immune system, dissolve fat, build muscle, detoxifies ammonia, works against sleeplessness, offers protection to and regeneration of the liver, etc.

Scalp biopsy

Parts of the scalp are removed and examined.

Sebaceous gland

Are microscopic glands in the skin that secrete an oily/waxy matter, called sebum, to lubricate the skin and hair.


A disease of the skin and connective tissue that can cause hair loss over the affected areas.

Telogen phase

The resting phase, which immediately follows the transition phase. This is the last phase in which the club hair is pushed out by the growing new hair.

Terminal hair

Large, heavy pigmented hairs with a central medulla.


A predominantly male hormone which promotes the development of male characteristics.

Traction Alopecia

This refers to hair loss which occurs do to traction place on hair. Traction alopecia is commonly seen with braids, pony tails and other hairstyles which create traction on the scalp.


Microscopic examination of the roots of pulled out hair. It shows the relationship between hair in the growth phase (anagen phase), in the resting phase (telogen phase) and in the transition phase (catagen phase).


A modified version of the trichogram is the trichoscan. The trichoscan determines the hair density and the relation between growing and non-growing hairs on the scalp using images.

Vellous hair

Vellous hair is very short, fine light coloured hairs.