Re: Is there any treatment to increase the melanin level in fair skin?

First, let me apologize for the delay in answering this question.  I try 
not to let this happen, but sometimes I get busy and a question falls 
through the cracks.  Again, sorry.

The pigment-derived component of skin color is determined by the production 
of melanin in special skin cells called melanocytes.  Melanin is then 
distributed to the other predominant skin cell, the keratinocyte, where it 
is both stored and broken down.  An important hormonal influence on melanin 
production is called melanocyte-stimulating hormone (MSH).  This hormone is 
produced by the pituitary gland (and other cells) and acts on the 
melanocytes to stimulate melanin production.

You might imagine that two things could affect the overall level of melanin 
in skin - the rate of production and the rate of breakdown.  Interestingly, 
the difference between fair and dark skin (especially comparing Caucasian 
and Negroid skin) is mostly a manifestation of a lower rate of breakdown in 
darker skin.  However, when any given person is exposed to the sun, the 
darkening of the skin (i.e. tanning) is a result of increased production of 
melanin by the melanocytes.  This is really a protective response, i.e. an 
attempt to increase the UV-resistance of the skin when exposed to damaging 
sunlight.

It has long been an interest of drug companies to find a good way to 
stimulate tanning without having to expose the skin to sunlight (or tanning 
booths), since excessive light exposure is clearly correlated with an 
increased incidence of skin cancer.  An approach that has been taken is to 
try and increase melanin production by increasing MSH activity.  This seems 
very obvious - just give more of this hormone, and skin should darken.  In 
fact, MSH analogues have been derived that are effective in this regard.  
The names that I have seen applied to these are "Melanotan".  These are 
synthetic peptides that mimic the action of MSH.  However, I am not aware 
that such compounds are available commercially (anyone care to correct 
me?).  As near as I can tell, they are still in clinical trials and under 
development.  A major limitation is delivery of the drug - since it is a 
peptide, it cannot be taken as a pill, since it would be broken down by the 
gut.

Finally, I should also say that there are readily available "sunless" 
tanning lotions.  Some of these actually contain melanin.  But I think it 
is obvious that you are really just painting the skin in this case, and not 
really changing the melanin content in the cells.  Other tanning lotions 
contain dihydroxyacetone as the active ingredient.  I have been unable to 
confirm this, but I think that this agent acts to temporarily limit melanin 
breakdown, resulting in skin darkening.  Again, this only significantly 
affects the surface layer of the skin, and is very temporary.

Tom Wilson MD PhD