Mannatech Launches OsoLean(TM) Powder Fat Loss Product

Mannatech, Incorporated (NASDAQ: MTEX), a leading developer and provider of dietary supplements and skin care solutions, announces the launch of its new fat-loss product OsoLean™ powder. OsoLean™ whey protein supplement is an all-natural powder product that mixes with a variety of food and beverages so consumers can easily add it to any weight and fitness program.

Mannatech also launched the OsoLean™ Challenge among its independent Associates, who will track their waist circumference in inches while using OsoLean™ powder, in conjunction with the OsoLean™ Plan and exercise, during an eight week period between Sept. 4 and Dec. 31, 2008.* A number of Mannatech executives have also joined the challenge, sparking some friendly competition with Associates.

In a clinical study, OsoLean™ powder has been shown to help target fat loss and spare lean muscle when combined with the OsoLean™ Plan and proper exercise.* Additionally, whey protein and calcium from milk have been shown to promote fat loss while maintaining muscle in combination with a reduced-calorie diet and proper exercise.

"The launch of OsoLean™ powder is yet another milestone for our company,” said Dr. Robert Sinnott, chief science officer and senior vice president of Mannatech. "With this newest offering, we are on the forefront of protein peptide technologies that deliver outstanding results. It is an ideal dietary supplement product because it offers the consumer both convenience and the latest application of science to specifically target fat loss while maintaining lean muscle mass.”*

In developing OsoLean™ powder, Mannatech secured a patented process where specific parts of whey protein, called peptides, are separated and concentrated to ensure the optimal level of fat-loss peptides, making OsoLean™ powder different from ordinary whey protein.*

Mannatech first introduced OsoLean™ powder at MannaQuest, the company’s annual training convention that took place Sept. 3-6 in Chicago, Ill. OsoLean™ powder does not contain preservatives or fillers unlike most diet plans or meal replacement drinks that include synthetic flavors or sweeteners, preservatives and unnecessary calories. OsoLean™ powder also provides 20 percent of the recommended daily value of protein and 22 percent of calcium per serving.

For additional information about OsoLean™ powder, please visit www.MannatechOsoLean.com.

About Mannatech

Mannatech, Incorporated is a global wellness solutions provider of innovative, high-quality, proprietary dietary supplements, skin care products and weight and fitness products sold through independent associates and members located in the United States and the international markets of Canada, Australia, the United Kingdom, Japan, New Zealand, the Republic of Korea, Taiwan, Denmark, Germany, South Africa and is scheduled to open in Singapore during the fourth quarter of 2008. For more information please visit www.mannatech.com or www.allaboutmannatech.com.

Please Note: This release contains "forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, Section 21E of the Securities Exchange Act of 1934, as amended, and the Private Securities Litigation Reform Act of 1995. These forward-looking statements generally can be identified by use of phrases or terminology such as "intend” or other similar words or the negative of such terminology. Similarly, descriptions of Mannatech’s objectives, strategies, plans, goals or targets contained herein are also considered forward-looking statements. Mannatech believes this release should be read in conjunction with all of its filings with the United States Securities and Exchange Commission and cautions its readers that these forward-looking statements are subject to certain events, risks, uncertainties, and other factors. Some of these factors include, among others, Mannatech’s inability to attract and retain associates and members, increases in competition, litigation, regulatory changes, and its planned growth into new international markets. Although Mannatech believes that the expectations, statements, and assumptions reflected in these forward-looking statements are reasonable, it cautions readers to always consider all of the risk factors and any other cautionary statements carefully in evaluating each forward-looking statement in this release, as well as those set forth in its latest Annual Report on Form 10-K and Quarterly Report on Form 10-Q, and other filings filed with the United States Securities and Exchange Commission, including its current reports on Form 8-K. All of the forward-looking statements contained herein speak only as of the date of this release.