About Male Pattern Hair Loss

Male pattern hair loss (MPHL) is the most common type of hair loss and is characterised by thinning of the hair on the scalp, often resulting in a receding hairline and/or balding on the top of the head. It affects half of all men by the age of 50.1,2

Men inherit the genetic predisposition to MPHL. The gene (or set of genes) involved affect(s) the way the hair follicles (or certain of them) respond to androgens. Androgens (male hormones), particularly the major plasma androgen, testosterone, circulate in the blood either free or bound to protein.2

The genetic predisposition leads to an oversensitivity to a male hormone which all men have called dihydrotestosterone (DHT). DHT is created by the action of the isozyme type II 5 alpha-reductase on testosterone. DHT stimulates pubic hair, beard and chest hair but, in genetically predisposed individuals, it also causes hair follicles to shrink leading to MPHL.3

How DHT contributes towards hair loss

References:

  1. Hamilton JB. Male pattern hair loss in man: types and incidence. Ann N Y Acad Sci 1951; 53: 708–728.
  2. Sinclair R. Male pattern androgenetic alopecia. BMJ 1998; 317: 865–869.
  3. Kaufman KD. Androgen metabolism as it affects hair growth in androgenetic alopecia. Dermatol Clin. 1996; 14(4): 697–711.