Why Am I Losing My Hair?

Hair follicles, the factories that produce non-living hair, are composed of living cells.  These cells contain nucleated DNA.  The DNA in the cell nucleus functions something like software in a computer.  It dictates the way the living structures will be built and organized.  When, for whatever reason, the DNA software in scalp hair follicles receive instructions to slow down or stop growing, many changes occur in the protein synthesis portions of these cells.  

The most typical basis under which scalp hair follicles change from vibrant viable thriving growth to quiescence is within the context of the disorder known as common pattern hair loss, or androgenetic alopecia (AGA).   AGA is passed from generation to generation.  It can come from either or both sides of the family.  The phenotype (how bad the hair loss will be) is quite variable.  Some fortunate people lose very little hair throughout their lives.   Others begin balding at age 16 or 17.  As a general rule, the earlier one begins losing hair, the more extreme the pattern of hair loss will become.  Ultimately, in extreme examples of male AGA, a person can end up with a very thin strip of hair in the posterior scalp below the ears.   Extreme AGA in a female can lead to severe thinning, but even in such cases the feminine or juvenile hair line is retained. 

For a number of years, work at major medical universities has been underway to determine precisely which genes are responsible for hair growth and hair loss.  To date, approximately ten genes have been identified as those influencing, among other physiologic events, human scalp hair growth.   Ultimately, it is hoped that gene based therapies will become available wherein the DNA software may be reprogrammed such that it will continue directing the growth of healthy vigorous scalp hair throughout one's lifetime.

As a rule, nine year old children do not lose their hair due to AGA.  In men, it is thought that 20% experience pattern hair loss in their 20's, 30% in their 30's and so on.  In women, the onset of pattern hair loss is often tied to peri-menopausal changes in hormone levels. 

Circulating hormones are primary modulators of almost all physiologic processes, including scalp hair growth.  In particular, the androgen hormones exert a profound influence on hair.  Dihydrotestosterone (DHT), which is a metabolite of testosterone, is directly linked to the onset and progression of AGA.   Through various means, it was learned that persons refractory to DHT, even those genetically susceptible to losing hair,  did not suffer from pattern hair loss.  >From this observation, a new line of research was conceived.  This research seeks to bring to light the multifaceted biochemical pathways and processes that dictate how hair grows.

A number of drugs are now available to treat pattern hair loss.  Some, like finasteride, seek to block a certain step in the metabolism of DHT.  Others, like minoxidil, are thought perhaps to modify intracellular potasium channel ion transport, and thus lenthen the growing phase of the hair.  Both finasteride and minoxidil have been linked to negative side effects in certain persons.  Non-drug, botanically-derived hair loss treatments have recently been developed with a goal of providing clinical utility without concomitant negative side effects.