March 2012 in “Korean Journal of Microscopy” Quantum dot nanoparticles can penetrate skin and reach sebocytes through hair follicles.
106 citations
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June 1990 in “Journal of Investigative Dermatology”
162 citations
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August 2005 in “The journal of investigative dermatology/Journal of investigative dermatology” The new "differential stripping" method effectively measures how much substance gets into hair follicles.
15 citations
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October 2020 in “European journal of pharmaceutics and biopharmaceutics” Caffeine penetrates skin quickly through open hair follicles, but less through closed ones, with levels becoming equal after 22 hours.
82 citations
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May 2009 in “BJCP. British journal of clinical pharmacology/British journal of clinical pharmacology” Caffeine penetrates human skin in lab tests similarly to real-life conditions, but actual skin use is still essential for accurate results.