I found some (old) studies which finally confirm the ratio that RP recommends to be apply on skin.
It seems that 5x times the oral dose on skin is definitely the way to go.
http://jn.nutrition.org/content/59/2/171.full.pdf
http://www.nature.com/jid/journal/v32/n ... 95995a.pdf
http://www.nature.com/jid/journal/v32/n ... 95996a.pdf
It seems that 5x times the oral dose on skin is definitely the way to go.
http://jn.nutrition.org/content/59/2/171.full.pdf
http://www.nature.com/jid/journal/v32/n ... 95995a.pdf
http://www.nature.com/jid/journal/v32/n ... 95996a.pdf