I have a degree in dermatology and have studied the use of zinc as a method to cure acne and other skin related disorders for some time now, so I know what I'm talking about.
Honestly, ignore that comment made in the post by Diane P. She clearly has no experience. It has been proven that one can take up to a maximum of 100mg per day without experiencing hazardous side effects. However, the recommended daily allowance for the mineral is from 15mg to 60mg. For acne sufferers, an amount of 60-70mg of normal zinc is recommended or 30-50mg of chelated zinc.
If you taking zinc as a added supplement for your general health, an amount of 15mg (chelated zinc) or 30mg (zinc) is adequate.
Lastly, if a over the counter product is sold that contains a total of 50mg of chelated zinc then it can in no way pose a threat to your health, use the product you purchased daily and make sure to follow it's suggested intake.
Hope that helps.