Bismarck said:
It has a depot effect in the stratum corneum and is slowly going into the bloodstream.
I don't know if it really has much of a depot effect (where did you hear that, Bis?), but it was certainly absorbed to some extent from topical application in that study! Here's the full paragraph about that:
"Melatonin was resorbed by scalp skin and led to plasma levels of between 35 and 50 pg/mL, which were significantly higher than in the placebo group with constant levels of 5-10 pg/mL. There was a high inter- and intraindividual variability of melatonin levels in both the melatonin and the placebo group, although melatonin levels in the treatment group did not exceed the physiological night peak of 250 pg/mL."
It's fairly obvious now why they had their subjects use the melatonin topical in the evening! :wink:
Bryan