is ol ▁causes ▁de grad ation ▁of ▁col lagen , ▁acceler ating ▁skin ▁ag ing . ▁ ▁Anti - aging ▁supp lement s ▁are ▁used ▁to ▁treat ▁skin ▁ag ing . ▁ ▁Ph oto aging ▁ ▁Ph oto aging ▁has ▁two ▁main ▁concerns : ▁an ▁increased ▁risk ▁for ▁skin ▁cancer ▁and ▁the ▁appearance ▁of ▁dam aged ▁skin . ▁In ▁younger ▁skin , ▁sun ▁damage ▁will ▁he al ▁faster ▁since ▁the ▁cells ▁in ▁the ▁e pid erm is ▁have ▁a ▁faster ▁turn over ▁rate , ▁while ▁in ▁the ▁older ▁population ▁the ▁skin ▁becomes ▁th inner ▁and ▁the ▁e pid erm is ▁turn over ▁rate ▁for ▁cell ▁repair ▁is ▁lower , ▁which ▁may ▁result ▁in ▁the ▁der mis ▁layer ▁being ▁dam aged . ▁ ▁Function s ▁Sk in ▁performs ▁the ▁following ▁functions : ▁▁ ▁Prote ction : ▁an ▁an atom ical ▁bar rier ▁from ▁path og ens ▁and ▁damage ▁between ▁the ▁internal ▁and ▁external ▁environment ▁in ▁bod ily ▁defense ; ▁L anger h ans ▁cells ▁in ▁the ▁skin ▁are ▁part ▁of ▁the ▁adapt ive ▁imm une ▁system . ▁Pers p iration ▁contains ▁ly so zym e ▁that ▁break ▁the ▁b onds ▁within ▁the ▁cell ▁walls ▁of ▁b acter ia . ▁ ▁S ens ation : ▁contains ▁a ▁variety ▁of ▁n erve ▁end ings ▁that ▁react ▁to ▁heat ▁and ▁cold , ▁touch , ▁pressure , ▁v ibration , ▁and ▁t issue ▁injury ; ▁see ▁som atos ens ory ▁system ▁and ▁ha pt ics . ▁ ▁He at ▁reg ulation : ▁the ▁skin ▁contains ▁a ▁blood ▁supply