Exhibit 99.1
Robert C. Blattberg
35 Watergate Drive
Sarasota, FL 34236
December 21, 2009
Mr. J. Stanley Frederick
Mannatech, Inc
600 S. Royal Lane
Coppell, TX 75019
Dear Stan:
This letter is to notify you that I am resigning from the Board of Mannatech, Inc. immediately. I appreciate the opportunity you and the other Board members gave me to serve on the Board of Mannatech and I wish you and the company future success.
Regards,
/s/Robert C. Blattberg
Robert C. Blattberg