I respectfully disagree with J. Pike.
Based upon published research by several of the nation's top ag schools, such as Penn. St., LSU, Miss. St. Texas A&M, Clemson, etc. deer do get practically no nutritional benefit from NaCl only. But minerals high in calcium and/or useable phosphates are necessary for good health. Most comes from natural forbs. However using supplemental minerals such as Dicalcium Phosphate and other supplements which are high in useable calcium and phosohates, mixed with NaCl or Trace Mineral Salt will not only attract deer to ytour place but also help all game animals that use the licks with bone strength, calcium loss during pregnancy and strees during lactation. On the land I hunt, we have about 30 mineral lick areas and troughs located around the 3500 or so acres. We put out on the average about 1500# of NaCl and 750# of Di-Cal and/or hi-cal minerals each year. Have for well over a decade. We have trail camera photos of deer, coyotes, and racoons munching on this mix. Can I prove that these critters are better off? Nope ... but I am pretty certain from the improvement in antler mass, and the size of the does and fawns that we are doing some good as well as attracting them to the area.