Oral sunscreen

the pubmed link describes how about 4 times as much UV exposure is required to cause a person on oral ibuprofen to have reddened skin. Carotenes, as well as possibly astaxanthin and lutein are nutrients that accumulate at the dermis, changing people's color. chemically modifying these to be transparent should be possible (interestingly I read about a blue carotenoid, based on =-=-=- length, so a UV/transparent carotenoid might be possible)

link these two chemicals together to hyperconcentrate ibuprofen at the dermis, creating an even higher SPF equivalent.

Now, I thought of this as a beauty drug, possibly able to halve the reate of photoaging or better. That is it would preserve skin from cumulative UV damage, so I do not know if reducing erythema is the same thing, it might work though as a beauty preservation pill. Another possibility of course is to link the modified carotene to an aptamer that concentrates just at the dermis.