You should always check to see if it is restricted and carry proper documentation as mandated by the local government. In my experience, I have never once had a customs agent call out myself or my SO for personal supply of any kind of medicine/supplement in dozens of trips to various countries around world, including countries with very strict drug laws like SG/ID/TK. I tend to have a few dozen of various supplements and OTC drugs in labeled baggies, while my SO has a rather significant supply of Rx drugs. Have only made a few trips to Turkey, but they were no more intrusive than anywhere else. YMMV, but I would venture to guess that most places really don't care as long as the quantities are reasonable for personal use and they are not obviously being hidden somewhere in a secret compartment.