5-alpha Reductase

An enzyme which converts testosterone to dihydrotestosterone (DHT), which is the hormone that triggers Androgenetic Alopecia in individuals who are genetically susceptible.

Alopecia

Alopecia is the scientific term for hair loss.  There are many different types of Alopecia.

Alopecia Areata

Alopecia Areata is the medical term for hair loss, which occurs in patches on the scalp. Also known as Immune system disorder in which hair follicles stop producing hairs. Also know as the medical term for hair loss or baldness in general.

Alopecia Totalis

Alopecia Universalis

Alopecia Universalis is the term for hair loss which occurs over the entire body.

Anagen

This is the actively growing phase of the hair cycle which lasts about seven years in a healthy person.

Androgenetic Alopecia

This is the term for male or female pattern baldness which depends on the genetic predisposition of the hair follicles and the levels of DHT in the body. Also known as hereditary male pattern baldness

Androgens

Male hormones that produce and protect male characteristics within the male body. The most common being testosterone.

Antiandrogen

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

Azelaic Acid

Azelaic acids like Retin-A is more commonly used in the treatment of acne and other skin conditions. Recently the potential effect in the treatment of androgenetic alopecia has been looked at and discussed.

Baldness

Receding hairline.

Canites

Term given to grey hair, it is actually a mixture of white and coloured hairs.

Catagen

Transition phase of the hair growth cycle. It lasts approximately 2-3 weeks, and signals the end of active growth i.e. the resting phase.

Cortex

The cortex is the main structure of the hair shaft. The cortex determines the colour and texture of the hair as the pigment is contained there.

Cuticle

The outer layer of hair typically comprised of 6-8 layers of overlapping cells

Cyproterone Acetate

This drug is normally used to reduce sex drive in men who have an excessive sex drive. 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. The dermal papilla contains nerves and blood vessels which supply glucose for energy and amino acids to make keratin.

DHT

DHT is a male hormone that is suggested to be the main cause for the miniaturisation of the hair follicle and for hair loss. DHT is formed when the male hormone testosterone interacts with the enzyme 5-alpha reductase.

Finasteride

Finasteride is the generic name of the brand name drug Proscar. Tablets of Finasteride have been marketed under the brand name Propecia, as a treatment for hair loss.

Follicle

The hair follicle houses the root of the hair.

Germinal Matrix

The source of hair growth.

Hair bulb

The base of a hair.

Hair growth cycle

This life/growth cycle is divided into three phases:
Anagen - active hair growth. Lasts between two to seven years.
Catagen - transitional. Lasts two to three weeks.
Telogen - resting phase. At the end of the resting phase (two to three months) the hair is shed and a new hair replaces it and the growing cycle starts again.

Hair root

The portion of the hair that stretches from the surface of the skin to the hair bulb.

Hair shaft

The section of the hair that extends above the surface of the skin.

Hirsutism

Excessive hair growth in women, ranging from few dark chin hairs to mustache sideburns and hairy chest.

Involutional alopecia

More and more hair follicles go into a telogenic, or resting, phase, and the remaining hairs become shorter and less in number. Gradual thinning with age.

Keratin

A fibrous insoluble protein that is the main structural element in hair, nails, feathers, and hooves.

Male pattern baldness

The natural occurrence of hair loss in men. Also known as androgenetic alopecia.

Medulla

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

Minoxidil

Minoxidil is the generic name of the brand name drug Rogaine/Regaine. Minoxidil is available in the form of a topical lotion with varying strength from 2% to 5%. Minoxidil was the first drug to be approved by the FDA for the treatment of androgenetic alopecia.

Pigment

Substance that gives colour. There are two types of hair pigments, melanin (black or brown hair colour) and pheomelanin (red or yellow hair colour).

Retin-A

Retin-A is a brand name for a topical gel or cream normally used in the treatment if acne.

Saw Palmetto

Saw Palmetto is a Natural Herb that has been shown to be an effective antiandrogen.

Scalp

Tissue covering the skull.

Scleroderma

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

Sebum

An oily substance that is produced by the sebaceous glands.

Sprionolactone

This is a drug normally used to treat high blood pressure, however it also acts as an antiandrogen and is used in the treatment of androgen related disorders such as female pattern baldness and hirsuitism.

Telogen

This refers to the shedding or falling phase of the hair cycle.

Telogne effluvium

Hair thinning over the scalp or other parts of the body that occurs because of changes in the growth cycle of hair.

Terminal hair

Large, heavy pigmented hairs with a central medulla.

Testosterone

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

Toxic Alopecia

Sudden loss of hair resulting from exposure to chemicals or radiation (one example is chemotherapy).

Traction Alopecia

Loss of hair ensuing from regular pulling. Some examples are tight braiding (corn rows), pony tails and other hairstyles which create traction on the scalp, sometimes over Alopecia Areata

Tretinoin

Retin-A is a brand name for a topical gel or cream normally used in the treatment of acne.

Trichotillomania

A psychological disorder of tearing out one's own hair.

Vellous hair

Vellous hair is very short, fine light coloured hairs.