Document:

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                                                                    EXHIBIT 10.1

                                    AGREEMENT

      This non-exclusive Consultancy and Lock-Up Agreement ("Agreement") is made
and effective this 1st day of october 2001, by and between Mannatech,
Incorporated ("Company"), a Texas corporation with its principal place of
business located at 600 S. Royal Lane, Suite 200, Coppell, Texas 75019 and Stan
Fredrick ("Consultant") whose principal address is 3509 Wingren, Irving, Texas
75062.

                                   WITNESSETH:

      WHEREAS, Company is in the business of operating a network marketing
company which sells a proprietary line of dietary supplements, cosmetics and
over-the-counter products ("Products") and which compensates its distributors
("Associates") by a defined compensation plan;

      WHEREAS, in connection with the development of its business, Company is
desirous of securing Consultant's unique expertise in the areas of the direct
selling industry and business advice in general ("Consultancy"); and

      WHEREAS, Company intends to enter into a confidential relationship with
the Consultant whereby the Consultant will acquire an intimate knowledge and
access to Company's business and will obtain or has obtained specialized skills.
Company will permit the Consultant to have access to and to utilize the business
goodwill, cost and pricing information, Confidential Information (as defined
herein) and various trade secrets of Company, including without limitation,
marketing programs, business relationships, customer lists, business plans,
financial data, privileged legal information and other compilations of
information developed by Company and essential to its business;

      WHEREAS, the Consultant will be a key Consultant of Company and Company
will provide or has provided the Consultant with access to such Confidential
Information and trade secrets in reliance upon the Consultant entering into this
Agreement;

      WHEREAS, the Consultant or a trust controlled by him will purchase,
simultaneously with the execution of this Agreement, certain shares of Common
Stock of the Company ("Common Stock") and Company desires to restrict sales of
the Common Stock;

      WHEREAS, the Consultant has agreed to certain restrictions on the sale of
shares of the Common Stock subject to the terms and conditions of this
Agreement; and

      NOW, THEREFORE, in consideration of the mutual covenants and agreements
contained herein and upon the terms, conditions and provisions hereinafter set
forth, Company and the Consultant do hereby agree as follows:

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                                   ARTICLE I.
                             DUTIES AND COMPENSATION

1.1   Term. The term of this Agreement, unless otherwise modified in writing, is
      for a two (2) year calendar period, beginning September 30, 2001 and
      ending September 30, 2003 (the "Term"). The Term shall be extended
      automatically for an additional successive one (1) calendar year period as
      of each anniversary of the effective date after the initial term; provided
      however, that if either party shall give written notice to the other at
      least thirty days prior to such anniversary, then no such automatic
      extension shall occur and Consultant's obligations under this Agreement
      shall terminate on the day prior to such anniversary. Notwithstanding the
      foregoing, the Consultancy will remain in effect as long as Consultant
      owns the Common Stock.

1.2   Compensation. Consultant is engaged at an annual payment of $185,000
      payable on a monthly basis in equal installments, the first payment being
      due upon execution hereof and all payments due in equal monthly
      installments thereafter.

1.3   Expenses. Company will reimburse the Consultant for the reasonable cost of
      any travel and/or incidental expenses for travel undertaken in pursuit of
      the Consultancy. The advance approval for travel, and subsequent
      reimbursement of expenses shall be made through the Chief Executive
      Officer ("CEO") and reimbursement shall occur in accordance with the
      Company Expenditure Procedure, which is attached hereto and incorporated
      herein as Exhibit "A" - "Policy".

1.4   Independent Contractor. The Parties agree that this Agreement shall not be
      considered an employment agreement nor is it an offer for employment. The
      relationship between Consultant and Company is that of independent
      contractor under a "work for hire" arrangement and that all work product
      developed by Consultant for the Company shall be deemed owned and assigned
      to Company in accordance with Article IV hereof. This Agreement is not
      authority for Consultant to act for Company as its agent or make
      commitments for the Company. Consultant will not be eligible for any
      employee benefits, nor will Company make deductions from fees to the
      consultant for taxes, insurance, bonds or the like. Consultant retains the
      discretion in performing the tasks assigned, within the scope of work
      specified.

1.5   Scope of Duties. The Consultant and Company agree that upon reasonable
      notice and mutual agreement as to each instance, his undertakings under
      the terms of this Agreement shall include, but not necessarily be limited
      to the following activities and other tasks as requested (hereinafter
      collectively referred to as "Services"):

      1.5.1 Avail himself to the CEO and Co-Chairmen or Chairman of the Board of
            Directors to provide counsel and business in the areas of corporate
            governance, sales and marketing;
      1.5.2 Provide business advice and share business expertise with the Board
            of Directors;
      1.5.3 Work with senior management of Company to promote and extend
            Company's business and help develop new business;
      1.5.4 Participate in presentations and the start-up phases of new
            projects;
      1.5.5 Use his best efforts to further public awareness of Company in the
            United States and overseas through speeches and/or promotion of
            Company and its products in general;

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      1.5.6  Appear as a public speaker at Corporate-sponsored events;
      1.5.7  Meet with various high ranking Associates to provide various advice
             and intervention between Company and the sales force; and
      1.5.8  Act as advisor to the CEO and senior management team to provide
             industry trends and updates pertaining to direct selling industry.

The Consultant further agrees that:

      1.5.9  Under the terms of this Agreement and his Consultancy, he will not
             have any authority to act on behalf of Company in the areas of
             discussion, negotiation or execution of any contracts or agreements
             in an attempt to bind Company (or its subsidiaries) and will not
             purport the same to any third party. Any agreements, plans,
             proposals, programs, incentives or undertakings of Company must
             first be proposed to the Company Board of Directors and/or CEO (as
             the case may be) and approved by the same prior to any discussion
             with third-parties, including Company Associates. Any contracts,
             plans, programs, incentives or undertakings proposed by the
             Consultant and approved by the Board or CEO, as the case may be,
             will be submitted to the General Counsel in accordance with
             Corporate Procedure PLE01002, or any other policy applicable to
             this provision as required by the Company in its Policies and
             Procedures as added to, modified, or deleted from time-to-time.
      1.5.10 During the term of this Agreement, the Consultant agrees that
             neither he nor any family member (such to be defined as one
             residing in the same household) operate or participate in the
             operation of a Company Associate position in any manner whatsoever.
      1.5.11 Consultant agrees to perform diligently and to the best of
             Consultant's abilities the duties and services appertaining to such
             Consultancy, as well as such additional duties and services
             appropriate to such Consultancy or as shall be designated by the
             Board of Directors upon which the Parties may mutually agree from
             time-to-time. The Consultant also agrees that his Consultancy is
             subject to the current and future policies and procedures
             maintained and established by Company. The Consultant shall devote
             his best efforts, ability and attention to the business of Company
             and the performance of the Consultant's duties as contemplated
             herein.
      1.5.12 Consultant acknowledges and understands that from time to time the
             Consultant's duties may require the Consultant to work on-site
             and/or at a non-company location. In such instance, the Consultant
             agrees to comply with all of the policies, procedures and
             directives relevant to working at such non-company location.
      1.5.13 During the term of this Agreement, the Company may in the event of
             a vacancy on the Board of Directors, consider the Consultant for
             possible candidacy for such vacancy and may submit the Consultant's
             name to the Nominating Committee, pursuant to any guidelines
             established by such Nominating Committee of the Board of Directors
             for consideration, in filling any such vacant if such seat is
             vacant.

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                                   ARTICLE II
                                LOCK-UP AGREEMENT

2.1   Lock-Up Period. Except as contemplated in this Agreement, Consultant
      hereby agrees during the term of this Consultancy Agreement (the "Lock-Up
      Period"), he will not offer, sell, assign, pledge, transfer, hypothecate,
      contract to sell, grant any option for the sale of or otherwise dispose
      of, directly or indirectly, and except to a family member or family
      controlled trust, upon prior written notification to the Company, any of
      the Common Stock or securities convertible into or exchangeable or
      exercisable for any shares of Common Stock, enter into a transaction which
      would have the same effect, or enter into any swap, hedge or other
      arrangement that transfers, in whole or in part, any of the economic
      consequences of ownership of the Common Stock, whether any such
      aforementioned transaction is to be settled by delivery of the Common
      Stock or such other securities, in cash or otherwise, or publicly disclose
      the intention to make any such offer, sale, pledge or disposition, or to
      enter into any such transaction, swap, hedge or other arrangement,
      without, in each case, the prior written consent of Company. Any
      securities received upon exercise of options granted to Consultant will
      also be subject to the provisions set forth in this Article II. Consultant
      agrees and consents to the entry and stop transfer instructions with
      Company's transfer agent against any transfer of shares of Common Stock
      held directly or indirectly by Consultant not in compliance with this
      Agreement.

2.2.  Extended Lock-Up. The restrictions and obligations of Consultant under
      Section 2.1 shall be extended without any further action (the "Extended
      Lock-Up Period") in the event the Consultancy Agreement is extended
      pursuant to the terms of Section 1.1 hereof. The Lock-Up shall be extended
      so long as the Company continues to pay the Consultant in accordance with
      Section 1.2 hereof or until the Company makes a secondary offering of its
      common stock.

                                  ARTICLE III.
                      NON-COMPETITION and NON-SOLICITATION

3.1   Non-Competition. To the full extent permitted by law, the Consultant will
      not for a period of one (1) year following the termination of this
      Agreement:

      3.1.1 Attempt to cause any person, firm or corporation, which is a
            customer of or has a contractual relationship with Company
            (including its Associates) at the time of termination of this
            Agreement to terminate such relationship with Company. This
            provision shall apply regardless of whether such customer has a
            valid contractual arrangement with Company;
      3.1.2 Attempt to cause any employee of Company to leave such employment;
      3.1.3 Engage any person who was an employee of Company at the time of the
            termination of this Agreement or cause such person otherwise to
            become associated with the Consultant or with any other person,
            corporation, partnership or other entity with which the Consultant
            may thereafter become associated; or

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      3.1.4 Engage in any activity or perform any services competitive with any
            business conducted by Company, and in any country in which Company
            operates, at the time of execution of this Agreement other than
            duties that occur under the course of his current business in which
            he participates, of which he has fully disclosed to the Company, as
            indicated and attached hereto as Exhibit "B", upon the execution of
            this Agreement.

            As set forth above, the Consultant acknowledges that the foregoing
            non-competition and non-solicitation covenants are ancillary to or a
            part of an otherwise enforceable agreement, such being the general
            agreement of this Consultancy and its related agreements concerning
            confidentiality and non-disclosure of Confidential Information and
            non-solicitation. The Consultant acknowledges that at the time that
            this non-competition covenant is made, that the limitations as to
            time defined herein and that the limitations as to geographic area
            are reasonable and do not impose a greater restraint than is
            necessary to protect the goodwill or other business interests of
            Company.

3.2   Consultant agrees that in the highly competitive business in which Company
      is engaged, personal contact is of primary importance in securing new and
      retaining present Associates and customers. The Consultant also agrees
      that Company has a legitimate interest in maintaining its relationships
      with its Associates and customers and that it would be unfair for the
      Consultant to solicit the business of Company's Associates and customers
      in relation to the Company's current business and exploit the personal
      relationships that he develops with Company's Associates and customers by
      virtue of his access to them as a result of this Consultancy.

3.3   Consultant shall be bound by and abide by all reasonable policies and
      procedures of Company that are within the scope of his Consultancy and
      that are in effect during the term of his Consultancy.

3.4   Consultant acknowledges and agrees that he owes a fiduciary duty of
      loyalty, fidelity, and allegiance to act at all times in the best
      interests of Company. In keeping with these duties, Consultant shall make
      full disclosure to Company of all business opportunities pertaining to
      Company's present business and shall not appropriate for Consultant's own
      benefit business opportunities concerning such business.

3.5   The Parties agree that during the term of this Agreement and thereafter,
      they will not disparage each other or their respective Affiliates.

3.6   Irrespective of the term of this Agreement, and in consideration of the
      promises specified in Article II of this Agreement, Company agrees as
      follows:

      3.6.1 To provide specialized training as specified herein; and
      3.6.2 To provide the Consultant with access to Company's software and
            files, records, marketing procedures, processes, computer programs,
            compilations of information, records, Associate and client
            requirements, pricing techniques, lists, formulae, lists identifying
            Associates, partners, potential investors, methods of doing business
            and other Confidential Information, as defined in Article III
            hereof, which is regularly used in the operation of the business of
            Company.

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3.7   Nothing contained herein shall prevent the Consultant from undertaking or
      continuing business interests and endeavors that do not directly relate to
      the Company's present business, that he has upon execution hereof and/or
      making financial investments as he sees fit.

                                   ARTICLE IV.
                            CONFIDENTIAL INFORMATION

4.1   During the course of the Consultancy the Consultant will be given access
      to Company's Confidential Information concerning Products and the business
      operations of Company.

4.2   The Consultant acknowledges that in the further course of the Consultancy
      with Company, the Consultant will gain a close, personal and special
      influence with Company's customers and will be acquainted with all of
      Company's business, particularly Company's Confidential Information
      concerning the business of Company and its affiliates.

4.3   For purposes of this Agreement "Confidential Information" shall mean and
      include information disclosed to the Consultant or known by the Consultant
      through the Consultant's consultancy with Company, not generally known in
      Company's industry, or otherwise known to Consultant or received from a
      source other than the Company about Company's products, processes and
      services, including but not limited to information concerning inventions,
      trade secrets, research and development, as well as all data or
      information concerning customers (including, Associates), customer lists
      (including downline reports and similar reports of business activities and
      relevant information concerning persons who conduct the same), prospect
      lists, mailing lists, sales leads, contracts, financial reports, sales,
      purchasing, price lists, product costs, marketing programs, marketing
      plans, business relationships, business methods, accounts payable,
      accounts receivable, accounting procedures, control procedures and
      training materials.

4.4   The Consultant recognizes that his position with Company is one of the
      highest trust and confidence by reason of the Consultant's access to the
      Confidential Information and the Consultant agrees to use his best efforts
      and will exercise utmost diligence to protect and safeguard the
      Confidential Information. In this respect, the Consultant agrees that
      fulfilling the obligations of this Article IV is part of the Consultant's
      responsibilities with Company for which the Consultant has been retained
      as a Consultant and for which the Consultant will receive consideration
      therefor.

4.5   Except as may be required by Company in connection with and during the
      Consultancy with Company, or with the express written permission of
      Company, the Consultant shall not, either during his work as a Consultant
      with Company or at any time thereafter, directly or indirectly, download,
      print out, copy, remove from the premises of Company, use for his own
      benefit or for the benefit of another, or disclose to another, any
      Confidential Information of Company, its customers, contractors, or any
      other person or entity with which Company has a business relationship.

4.6   Consultant agrees that all files, memoranda, data, notes, records,
      drawings, charts, graphs, analyses, letters, reports or other documents or
      similar items made or compiled by the Consultant, made available to him or
      otherwise coming into his possession during the Consultancy concerning any
      process, apparatus or products manufactured, sold, used, developed,
      investigated or considered by Company concerning the Confidential
      Information or concerning any other business or activity of Company shall
      remain at all

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      times the property of Company and shall be delivered to Company upon
      termination of this Agreement or at any other time upon request.

4.7   The Consultant agrees that during the term of this Agreement or upon
      termination thereof, and if requested by Company to do so, he will sign an
      appropriate list of any and all Confidential Information of Company of
      which he has knowledge about or which he has acquired information.

4.8   The Consultant acknowledges that the violation of any of the provisions of
      this Section 4 will cause irreparable loss and harm to Company which
      cannot be reasonably or adequately compensated by damages in an action at
      law, and accordingly, Company will be entitled, without posting bond or
      other security, to injunctive and other equitable relief to enforce the
      provisions of this Section 4; but no action for any such relief shall be
      deemed to waive the right of Company to an action for damages.

                                    ARTICLE V
                         RESULT OF CONSULTANT'S SERVICES

5.1   Company will be entitled to and will own all the results and proceeds of
      the Consultant's services under this Agreement, including without
      limitation, all rights throughout the world to any copyright, patent,
      trademark or other right and to all ideas, inventions, products, programs,
      procedures, formats and other materials of any kind created or developed
      or worked on for the Company by the Consultant during his consultancy with
      Company; the same shall be the sole and exclusive property of Company; and
      the Consultant will not have any right, title, or interest of any nature
      or kind therein. Without limiting the foregoing, it will be presumed that
      any copyright, patent, trademark or other right and any idea, invention,
      product, program, procedure, format or material created, developed or
      worked on by the Consultant for the Company at any time during the term of
      this Agreement will be a result or proceed of his services under this
      Agreement. The Consultant will take such action and execute such documents
      as Company may request to warrant and confirm Company's title to and
      ownership of all such results and processes and to transfer and assign to
      Company any rights which he may have therein. The Consultant's right to
      any compensation under this Agreement will not constitute a lien on any
      results or proceeds of the Consultant's services under this Agreement.

5.2   During the term of this Agreement and without further remuneration,
      Company shall have the right to use the Consultant's name, voice,
      likeness, and similar characteristics for the purposes of advertising,
      promoting, selling and otherwise merchandising the Company for which
      services are retained under this Agreement in the United States and all
      other countries in which Company conducts business. During the term of
      this Agreement, Company shall be the sole owner and have use and control
      of all promotional materials and trade literature ("Promotional
      Materials") produced for Company bearing the Consultant's image, likeness,
      voice or name. Company shall be free to dispose of and treat in any way
      all Promotional Materials as contemplated hereby, including but not
      limited to selling, advertising, distributing, and permitting use in other
      mediums with prior approval of the Consultant, of which, such approval
      shall not be unreasonably withheld.

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                                   ARTICLE VI
                                   TERMINATION

This Agreement shall become null and void, and no further payment obligations
shall become due upon the death of the Consultant.

                                   ARTICLE VII
                                  MISCELLANEOUS

7.1   Future Agreement. Should this Agreement expire in accordance with its
      terms, the Parties may choose to renew this Agreement on mutually agreed
      upon terms and conditions, such to be governed by a separate agreement.

7.2   Enforcement. It is the express intention of the Parties to this Agreement
      to comply with all laws applicable to the covenants and provisions
      contained in this Agreement. If any of the covenants contained in this
      Agreement are found to exceed in duration or scope permitted by law, it is
      expressly agreed that such covenant may be reformed or modified by the
      award or decree of an arbitrator, if applicable ("Reformation"). The
      Reformation shall be governed by a final judgment of a court of competent
      jurisdiction or other lawful constituted authority, as the case may be, to
      reflect a lawful and enforceable duration or scope, and such covenant
      automatically shall be deemed to be amended and modified so as to comply.
      If any one or more of the provisions contained herein shall for any reason
      be held invalid, illegal or unenforceable in any respect, even after
      formation, such invalidity, illegality or unenforceability shall not
      affect the enforceability or validity of any other provision contained in
      this Agreement, and this Agreement shall be construed as if such invalid,
      illegal or unenforceable provision had never been contained herein.

7.3   Adequacy of Consideration; Separate Agreements. The Consultant agrees that
      the agreements, non-competition agreements, nondisclosure agreements, and
      non-solicitation agreements set forth herein each constitute separate
      agreements, independently supported by good and adequate consideration and
      shall be severable from the other provisions of this Agreement and shall
      survive the termination thereof.

7.4   Representation and Warranties. Consultant represents and warrants that:

      7.4.1 Consultant has no obligations, legal or otherwise, inconsistent with
            the terms of this Agreement or with Consultant's undertaking this
            relationship with Company;
      7.4.2 With respect to Article II hereof, all of the shares of Common Stock
            held by Consultant are owned of record and beneficially by
            Consultant and that Consultant owns such Common Stock free and clear
            of any claims, liens, encumbrances, pledges, security interests or
            other arrangements or restriction whatsoever, except for such legend
            and related transfer restrictions as required under the Securities
            Act of 1933, as amended;
      7.4.3 The performance of the Services called for by this Agreement do not
            and will not violate any applicable law, rule or regulation or any
            proprietary or other right of any third party;

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      7.4.4 The Consultant will not use in the performance of his
            responsibilities under this Agreement any confidential information
            or trade secrets of any other person or entity;
      7.4.5 The Consultant has not entered into or will enter into any agreement
            (whether oral or written) in conflict with this Agreement except
            those enterprises otherwise disclosed in section 3.1.4 hereof.

7.5   Agreement to Perform Necessary Acts. Consultant agrees to perform any
      further acts and execute and deliver any documents that may be reasonably
      necessary to carry out the provisions of this Agreement.

7.6   Compliance with Law. In connection with his services rendered hereunder,
      Consultant agrees to abide by all federal, state, and local laws,
      ordinances and regulations.

7.7   Injunctive Relief. The Consultant recognizes and acknowledges that damages
      in the event of his breach of certain provisions of this Agreement would
      be inadequate, and the Consultant agrees that Company, in addition to all
      other remedies it may have, shall have the right to injunctive relief via
      arbitration if there is a breach by the Consultant of any one or more of
      the provisions contained in Articles III and IV hereof.

7.8   Arbitration. Arbitration, including the right to invoke injunctive relief
      and any emergency relief or measures provided for, shall be the exclusive
      remedy for any and all disputes, claims or controversies, whether
      statutory, contractual or otherwise, between Company and the Consultant
      concerning the Consultancy or the termination thereof. In the event either
      party provides a Notice of Arbitration of Dispute to the other party,
      Company and the Consultant agree to submit such dispute or controversy,
      whether statutory or otherwise, to an arbitrator or arbitrators selected
      from a panel of arbitrators of the American Arbitration Association
      located in Dallas, Texas. The effective rules at the time of the
      commencement of the Commercial Arbitration of the American Arbitration
      Association shall control the arbitration. In any arbitration proceeding
      conducted subject to these provisions, the arbitrator(s) is/are
      specifically empowered to decide any question pertaining to limitations,
      and may do so by documents or by a hearing, in his or her sole discretion.
      In this regard, the arbitrator may authorize the submission of pre-hearing
      motions similar to a motion to dismiss or for summary adjudication for the
      purposes of consideration in this matter. The arbitrator's decision will
      be final and binding upon the Parties. The Parties further agree to abide
      by and perform any award rendered by the arbitrator. Each party in such
      proceeding shall pay its own attorney's fees. In rendering the award, the
      arbitrator shall state the reasons therefor, including any computations of
      actual damages or offsets, if applicable.

7.9   Notices. Notices required to be given under this Agreement shall be in
      writing and shall be deemed to have been given and received when
      personally delivered, or when mailed by registered or certified mail,
      postage prepaid, return receipt requested, or when sent by overnight
      delivery service to the address as first written above.

7.10  No Agency. This Agreement does not constitute a joint venture or
      partnership of any kind between Company and the Consultant.

7.11  Assignment. In the event the Consultant assigns the Common Stock to a
      family member or trust ("Assignee") as contemplated in Section 2.1, the
      Assignee, its

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      successors, representatives and assigns, whether individually and/or
      collectively, shall be bound by all of the terms and conditions of this
      Agreement.

7.12  Waiver. A waiver by either party of any term or condition of this
      Agreement in any instance shall not be deemed or construed to be a waiver
      of such term or condition for the future, or any breach of such term or
      condition.

7.13  Authority. The Parties represent that they have full capacity and
      authority to grant all rights and assume all obligations they have granted
      and assumed under this Agreement.

7.14  Captions. The headings of the sections in this Agreement are intended
      solely for convenience of reference and are not intended and shall not be
      deemed for any purpose whatsoever to modify or explain or place
      constriction upon any of the provisions of this Agreement.

7.15  Governing Law. The Parties hereto agree that this Agreement shall be
      governed by the laws of the State of Texas without regard to the conflicts
      of law principles. The Parties further agree that exclusive jurisdiction
      and venue to enforce the arbitration provisions of this agreement shall be
      in a state or federal court of appropriate jurisdiction in Dallas County,
      Texas. Each party consents to personal jurisdiction in Dallas County,
      Texas, for any action to enforce arbitration including any further rules
      provided for emergency or extraordinary relief, as to this Agreement.

7.16  Disclosure. Each of the Parties agree to keep confidential the specific
      terms of this Agreement, and shall not disclose the terms of this
      Agreement to any person except the financial, tax and legal advisors of
      the other (and the Board of Directors of Company) unless required to
      disclose the same to others by legal process, in which event the Party so
      ordered shall first give notice to the other Party and an opportunity to
      seek a protective order. This Agreement may be disclosed or appended, as
      an exhibit to any securities filing required to be made by Company.
      However, after having been so disclosed or appended, the Consultant shall
      have no further duty of confidentiality concerning this Agreement, as set
      forth in this paragraph.

7.17  Approvals and Consents. This Agreement is subject to the approval of the
      Board of Directors and the Compensation Committee of Company.

7.18  Consultant Acknowledgement. The Consultant affirms and attests by signing
      this Agreement that he has read this Agreement before signing it and that
      he fully understands its purposes, terms, and provisions, which he hereby
      expressly acknowledges to be reasonable in all respects. The Consultant
      further acknowledges receipt of one (1) copy of this Agreement.

7.19  Counterparts. This Agreement may be executed in multiple counterparts, any
      one of which will be deemed an original, but all of which will constitute
      one and the same instrument.

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IN WITNESS WHEREOF, this Agreement is executed by the Parties hereto, effective
as of the 30th day of September, 2001.

CONSULTANT:

/s/ J. Stanley Fredrick
------------------------------------
Stan Fredrick

COMPANY:

MANNATECH, INCORPORATED
A Texas Corporation

By:  /s/ Stephen D. Fenstermacher
     -------------------------------
     Stephen D. Fenstermacher
Its: Chief Financial Officer

                                       11<PAGE>

                                                                    EXHIBIT 10.2

                               AMENDMENT AGREEMENT

            This Amendment Agreement ("Agreement") is entered into by and
between Charles E. Fioretti ("Fioretti") and Mannatech, Incorporated ("Company")
as of this 24th day of September, 2001, and is in partial amendment of that
certain Standstill Agreement entered into by and between Fioretti and Company,
effective August 8, 2000, the terms and conditions of which are incorporated by
reference herein and as indicated and attached hereto as Exhibit "A" (the
"Standstill Agreement").

                                   WITNESSETH

            WHEREAS, Fioretti, as of September 26, 2001 is the holder of
4,190,848 shares of Company common stock, $.0001 par value per share (the
"Common Stock");

            WHEREAS, under the terms of the Standstill Agreement and in
accordance with Paragraph 3 thereof, Fioretti has transferred the Sale Shares,
as therein defined, to the Company and received the Purchase Price therefrom and
in consideration thereof, Fioretti also agreed to abide by the terms of
paragraph 6(a) - ("Lock Up Agreement");

            WHEREAS, Fioretti has received a bona fide, good faith offer from J.
Stanley Fredrick ("Purchaser") for the purchase of 3,500,000 shares of Common
Stock and a right of first refusal for all remaining Common Stock (collectively,
the "Offered Shares) for good and valuable consideration and has heretofore
notified the Company of the same in accordance with Paragraph 6(b) of the
Standstill Agreement;

            WHEREAS, the Company has no good faith interest in pursuing the
purchase of Offered Shares and is desirous of discharging the Lock-Up Agreement
for the sole purpose of allowing the transaction between Fioretti and Purchaser
as contemplated hereby to occur;

            NOW THEREFORE, in consideration of the agreements and obligations as
set forth herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto, intending to
be legally bound, hereby agree as follows:

                             STATEMENT OF AMENDMENT

      1.    Contingent upon the purchase of the Offered Shares by Purchaser and
            under the conditions and in the amount as heretofore disclosed to
            the Company, and as a material inducement and upon which the Company
            relies upon entering this transaction, the Company does hereby agree
            to release Fioretti from the Lock-Up Agreement provision for the
            sole purpose of facilitating closing the transaction between the
            Purchaser and Fioretti has herein described.
      2.    The Parties mutually agree that each shall discharge the other of
            the obligation for Fioretti to sell and Company to purchase the
            "Sale Shares" as defined in the Standstill Agreement and in
            accordance with Paragraph 3 thereof.
      3.    The foregoing notwithstanding, this modification shall become null
            and void in the event that closing of the transaction between
            Fioretti and Purchaser fails to occur by September 30, 2001, 5:00
            p.m. CDT.
      4.    In all other things except the foregoing amendments, all of the
            terms and conditions of the Standstill Agreement and any Amendments
            thereto shall continue to remain in full force and effect.
<PAGE>

      5.    Nothing contained herein shall be deemed to alter, amend or modify
            any payment obligations, terms or conditions under the Renewal and
            Extension Promissory Note dated February 17, 1999 or any amendments
            thereof.
      6.    This Agreement may be executed in multiple counterparts, each of
            which shall be deemed an original and which taken together shall
            constitute one and the same agreement.

      IN WITNESS WHEREOF, the parties have caused this Agreement to be executed
      on the date first written above.

      /s/ Charles E. Fioretti
      ---------------------------------
      Charles E. Fioretti

      MANNATECH, INCORPORATED
      A Texas corporation

      By: /s/Stephen D. Fenstermacher
          -----------------------------
          Stephen D. Fenstermacher
      Its:Chief Financial Officer

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