Originally Posted by mrsD

Most people have adequate zinc. It might be a good idea to get
a blood test. Some drugs however, deplete zinc, and the ACE inhibitors are the mostly commonly used. Acid blocking drugs also are thought to affect zinc absorption. Vegans may become low in zinc over time, because of the phytate content of vegetables hinders absorption. If you are low in zinc the typical dose would be one OptiZinc a day or every other day.
Zinc is sometimes used to treat hair loss, especially in patients taking anti-seizure drugs.

NAC's most common side effect is a rash that some people get, but not all.

This monograph gives dosing for NAC:
http://www.webmd.com/vitamins-supple...TYL%20CYSTEINE