Letter of Transmittal

For Tender of Shares of Common Stock of

Mannatech, Incorporated

At a Purchase Price of $26.00 per Share

Pursuant to the Offer to Purchase Dated May 28, 2021

THE OFFER, PRORATION PERIOD AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, AT THE END OF FRIDAY, JUNE 25, 2021, UNLESS THE OFFER IS EXTENDED

The undersigned represents that I (we) have full authority to tender without restriction the certificate(s) and book-entry shares listed below. You are hereby authorized and instructed to deliver to the address indicated below (unless otherwise instructed in the boxes in the following page) a check representing a cash payment for shares of common stock, par value $0.0001 per share, of Mannatech, Incorporated (“Mannatech”) (collectively the “Shares”) tendered pursuant to this Letter of Transmittal, for purchase by us at a price of $26.00 per Share, to the seller in cash, less any applicable withholding taxes and without interest, upon the terms and subject to the conditions in the Offer to Purchase, dated May 28, 2021 (the “Offer to Purchase” and, together with this Letter of Transmittal, as they may be amended or supplemented from time to time, the “Offer”).

THIS FORM SHOULD BE COMPLETED, SIGNED AND SENT TOGETHER WITH ALL OTHER DOCUMENTS, INCLUDING YOUR CERTIFICATES FOR SHARES TO COMPUTERSHARE TRUST COMPANY, N.A. (THE “DEPOSITARY”) AT THE ADDRESS SET FORTH BELOW. DELIVERY OF THIS LETTER OF TRANSMITTAL OR OTHER DOCUMENTS TO AN ADDRESS OTHER THAN AS SET FORTH BELOW DOES NOT CONSTITUTE VALID DELIVERY. DELIVERIES TO MANNATECH OR GEORGESON SECURITIES CORPORATION (THE “DEALER MANAGER”), OR GEORGESON LLC (THE “INFORMATION AGENT”) WILL NOT BE FORWARDED TO THE DEPOSITARY AND THEREFORE WILL NOT CONSTITUTE VALID DELIVERY. DELIVERIES TO THE DEPOSITORY TRUST COMPANY WILL NOT CONSTITUTE VALID DELIVERY TO THE DEPOSITARY.

Method of delivery of the certificate(s) is at the option and risk of the owner thereof. See Instruction 2.

Mail or deliver this Letter of Transmittal, together with the certificate(s) representing your Shares, to:

If delivering by express mail, courier or other expedited service:	By mail:
Computershare Trust Company, N.A.	Computershare Trust Company, N.A.
c/o Voluntary Corporate Actions	c/o Voluntary Corporate Actions
150 Royall Street, Suite V	P.O. Box 43011
Canton, Massachusetts 02021	Providence, Rhode Island 02940-3011

Pursuant to the Offer to Purchase of up to 211,538 Shares, the undersigned encloses herewith and tenders the following certificates representing shares of Mannatech:

DESCRIPTION OF SHARES TENDERED
Name(s) and Address(es) of Registered Holder(s) If blank, please fill in exactly as name(s) appear(s) on share certificate(s)	Shares Tendered
	(Please fill in. Attach separate schedule if needed - See Instruction 3)
	Certificated Shares **			Book-Entry Shares
	Certificate No(s)*	Total number of Shares Represented by Certificate(s)*	Number of Shares Represented by Certificates Tendered**	Number of Shares Tendered***
	* Need not be completed if Shares are delivered by book entry transfer. ** Unless otherwise indicated, it will be assumed that all Shares represented by any certificates delivered to the Depositary are being tendered. See Instruction 4. *** Unless otherwise indicated, it will be assumed that all book entry shares are being tendered.

READ THE INSTRUCTIONS CAREFULLY BEFORE

COMPLETING THIS LETTER OF TRANSMITTAL.

Indicate below the order (by certificate number) in which Shares are to be purchased in the event of proration (attach additional signed list if necessary). If you do not designate an order and if less than all Shares tendered are purchased due to proration, Shares will be selected for purchase by the Depositary. See Instruction 14.
1st:	2nd:	3rd:
4th:	5th:

SCAN TO CA VOLUNTARY COY MTEX

YOU MUST SIGN THIS LETTER OF TRANSMITTAL WHERE INDICATED BELOW AND COMPLETE THE IRS FORM W-9 PROVIDED BELOW OR APPROPRIATE IRS FORM W-8.

This Letter of Transmittal is to be used if either certificates for shares of common stock, par value $0.0001 per share (the “Shares”), being tendered are to be forwarded with this Letter of Transmittal or, unless an Agent’s Message (defined below) is utilized, if delivery of Shares is to be made by book-entry transfer to an account maintained by the Depositary at The Depository Trust Company, which is referred to as the Book-Entry Transfer Facility, pursuant to the procedures set forth in Section 3 of the Offer to Purchase dated May 28, 2021 (as may be amended or supplemented from time to time, the “Offer to Purchase”). Tendering shareholders must deliver either the certificates for, or timely confirmation of book-entry transfer in accordance with the procedures described in Section 3 of the Offer to Purchase with respect to, their Shares and all other documents required by this Letter of Transmittal to the Depositary by 12:00 Midnight, New York City time, at the end of Friday, June 25, 2021 (as this time may be extended at any time or from time to time by Mannatech in its sole discretion in accordance with the terms of the Offer, the “Expiration Date”). Tendering shareholders whose certificates for Shares are not immediately available or who cannot deliver either the certificates for, or timely confirmation of book-entry in accordance with the procedures described in Section 3 of the Offer to Purchase with respect to, their Shares and all other documents required by this Letter of Transmittal to the Depositary by the time provided immediately above must tender their Shares in accordance with the guaranteed delivery procedures set forth in Section 3 of the Offer to Purchase. All capitalized terms not otherwise defined herein have the meaning ascribed to them in the Offer to Purchase.

If you want to retain the Shares you own, you do not need to take any action.

METHOD OF DELIVERY

☐    CHECK HERE IF CERTIFICATES FOR TENDERED SHARES ARE ENCLOSED HEREWITH.

☐    CHECK HERE IF TENDERED SHARES ARE BEING DELIVERED BY BOOK-ENTRY TRANSFER MADE TO AN ACCOUNT MAINTAINED BY THE DEPOSITARY WITH THE BOOK-ENTRY TRANSFER FACILITY AND COMPLETE THE FOLLOWING (ONLY PARTICIPANTS IN THE BOOK-ENTRY TRANSFER FACILITY MAY DELIVER SHARES BY BOOK-ENTRY TRANSFER):

    Name of Tendering Institution:

    Account Number:

    Transaction Code Number:

☐    CHECK HERE IF TENDERED SHARES ARE BEING DELIVERED PURSUANT TO THE GUARANTEED DELIVERY PROCEDURES OUTLINED IN SECTION 3 OF THE OFFER TO PURCHASE AND COMPLETE THE FOLLOWING:

    Name (s) of Registered Owner (s):

    Date of Execution of Notice of Guaranteed Delivery:

    Name of Institution that Guaranteed Delivery:

    Account Number:

CONDITIONAL TENDER

(See Instruction 13)

A shareholder may tender Shares subject to the condition that a specified minimum number of the shareholder’s Shares tendered pursuant to the Letter of Transmittal must be purchased if any Shares tendered are purchased, all as described in the Offer to Purchase, particularly in Section 6 of the Offer to Purchase. Unless at least the minimum number of Shares indicated below is purchased by Mannatech pursuant to the terms of the Offer, none of the Shares tendered will be purchased. It is the tendering shareholder’s responsibility to calculate that minimum number of Shares that must be purchased if any are purchased, and Mannatech urges shareholders to consult their own financial and tax advisors before completing this section. Unless this box has been checked and a minimum specified, the tender will be deemed unconditional.

☐    The minimum number of Shares that must be purchased, if any are purchased, is: _______________________ Shares.

If, because of proration, the minimum number of Shares designated will not be purchased, Mannatech may accept conditional tenders by random lot, if necessary. However, to be eligible for purchase by random lot, the tendering shareholder must have tendered all of his, her or its Shares and checked this box:

☐    The tendered Shares represent all Shares held by the undersigned.

ODD LOTS

(See Instruction 15)

Any shareholder who owns, beneficially or of record, a total of fewer than 100 Shares, may elect to have their Shares accepted for payment before any proration of or purchase of any other tendered Shares.

The undersigned either (check one box):

☐    is the beneficial or record owner of an aggregate of fewer than 100 Shares, all of which are being tendered, and elects the Odd Lot Priority,

OR

☐    is a broker, dealer, commercial bank, trust company or other nominee that (i) is tendering, for the beneficial owner(s) thereof, Shares with respect to which it is the record holder and (ii) believes, based upon representations made to it by such beneficial owner(s), that each such person was the beneficial owner of an aggregate of fewer than 100 Shares, all of which are being tendered, and elects the Odd Lot Priority for the Shares held by such beneficial owner(s).

LOST OR DESTROYED CERTIFICATE(S)

IF ANY STOCK CERTIFICATE REPRESENTING SHARES THAT YOU OWN HAS BEEN LOST, STOLEN OR DESTROYED, PLEASE CONTACT THE DEPOSITARY AT (877) 373-6374 PROMPTLY TO OBTAIN INSTRUCTIONS AS TO THE STEPS THAT MUST BE TAKEN IN ORDER TO REPLACE THE CERTIFICATE. THIS LETTER OF TRANSMITTAL AND RELATED DOCUMENTS CANNOT BE PROCESSED UNTIL THE PROCEDURES FOR REPLACING LOST OR DESTROYED CERTIFICATES HAVE BEEN FOLLOWED. PLEASE CONTACT THE DEPOSITARY IMMEDIATELY TO PERMIT TIMELY PROCESSING OF THE REPLACEMENT DOCUMENTATION. SEE INSTRUCTION 12.

NOTE: SIGNATURES MUST BE PROVIDED WHERE INDICATED BELOW. PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY.

Ladies and Gentleman:

The undersigned hereby tenders to Mannatech, Incorporated, a Texas corporation (“Mannatech”), the above-described shares of Mannatech’s common stock, par value $0.0001 per share (the “Shares”), at $26.00 per Share, to the seller in cash, less any applicable withholding taxes and without interest, upon the terms and subject to the conditions set forth in Mannatech’s Offer to Purchase dated May 28, 2021 (as amended or supplemented from time to time, the “Offer to Purchase”) and this Letter of Transmittal (which together, as they may be amended or supplemented from time to time, constitute the “Offer”), receipt of which is hereby acknowledged.

Subject to and effective on acceptance for payment of, and payment for, the Shares tendered with this Letter of Transmittal in accordance with, and subject to, the terms of the Offer, the undersigned hereby sells, assigns and transfers to, or upon the order of, Mannatech, all right, title and interest in and to all the Shares that are being tendered and irrevocably constitutes and appoints Computershare Trust Company, N.A. (the “Depositary”), the true and lawful agent and attorney-in-fact of the undersigned, with full power of substitution (such power of attorney being deemed to be an irrevocable power coupled with an interest), to the full extent of the undersigned’s rights with respect to such tendered Shares, to (a) deliver certificates for such tendered Shares or transfer ownership of such tendered Shares on the account books maintained by The Depository Trust Company (the “Book-Entry Transfer Facility”), together, in any such case, with all accompanying evidences of transfer and authenticity to, or upon the order of, Mannatech upon receipt by the Depositary, as the undersigned’s agent, of the aggregate purchase price with respect to such tendered Shares, (b) present such tendered Shares for cancellation and transfer on Mannatech’s books and (c) receive all benefits and otherwise exercise all rights of beneficial ownership of such tendered Shares, all in accordance with the terms of the Offer.

The undersigned hereby represents and warrants that the undersigned has full power and authority to tender, sell, assign and transfer the tendered Shares and, when the same are accepted for payment, Mannatech will acquire good title thereto, free and clear of all liens, security interests, restrictions, charges, claims, encumbrances, conditional sales agreements or other similar obligations relating to the sale or transfer of the tendered Shares, and the same will not be subject to any adverse claim or right. The undersigned will, on request by the Depositary or Mannatech, execute any additional documents deemed by the Depositary or Mannatech to be necessary or desirable to complete the sale, assignment and transfer of the tendered Shares (and any and all such other Shares or other securities or rights), all in accordance with the terms of the Offer.

All authority conferred or agreed to be conferred pursuant to this Letter of Transmittal shall be binding on the successors, assigns, heirs, personal representatives, executors, administrators and other legal representatives of the undersigned and shall not be affected by, and shall survive, the death or incapacity of the undersigned. Except as stated in the Offer to Purchase, this tender is irrevocable.

The undersigned understands that:

1.the valid tender of Shares pursuant to any of the procedures described in Section 3 of the Offer to Purchase and in the instructions to this Letter of Transmittal constitutes the undersigned’s acceptance of the terms and conditions of the Offer; Mannatech’s acceptance of the tendered Shares will constitute a binding agreement between the undersigned and Mannatech on the terms and subject to the conditions of the Offer;

2.it is a violation of Rule 14e-4 promulgated under the Securities Exchange Act of 1934, as amended, for a person acting alone or in concert with others, directly or indirectly, to tender Shares for such person’s own account unless at the time of tender and at the Expiration Date such person has a “net long position” in (a) the Shares that is equal to or greater than the amount tendered and will deliver or cause to be delivered such Shares for the purpose of tender to Mannatech within the period specified in the Offer, or (b) other securities immediately convertible into, exercisable for or exchangeable into Shares (“Equivalent Securities”) that is equal to or greater than the amount tendered and, upon the acceptance of such tender, will acquire such Shares by conversion, exchange or exercise of such Equivalent Securities to the extent required by the terms of the Offer and will deliver or cause to be delivered such Shares so acquired for the purpose of tender to Mannatech within the period specified in the Offer. Rule 14e-4 also provides a similar restriction applicable to the tender or guarantee of a tender on behalf of another person. A tender of Shares made pursuant to any method of delivery set forth in this Letter of Transmittal will constitute the tendering shareholder’s representation and warranty to Mannatech that (y) such shareholder has a “net long position” in Shares or Equivalent Securities being tendered within the meaning of Rule 14e-4, and (z) such tender of Shares complies with Rule 14e-4. Mannatech’s acceptance for payment of Shares tendered pursuant to the Offer will constitute a binding agreement between the tendering shareholder and Mannatech upon the terms and subject to the conditions of the Offer;

3.Mannatech will, upon the terms and subject to the conditions of the Offer, purchase Shares properly tendered and not properly withdrawn in the offer for $26.00 per Share (the “Purchase Price”) in cash, less any applicable withholding taxes and without interest, taking into account the number of Shares so tendered by tendering shareholders;

4.Mannatech reserves the right, in its sole discretion, to increase or decrease the Purchase Price and to increase or decrease the number of Shares sought in the Offer subject to applicable law. In accordance with the rules of the Securities and Exchange Commission, we may increase the number of Shares accepted for payment in the Offer by no more than 2% of the outstanding Shares without extending the Offer;

5.Shares properly tendered prior to the Expiration Date and not properly withdrawn will be purchased in the Offer at the Purchase Price, upon the terms and subject to the conditions of the Offer, including the proration (because more than the number of Shares sought are properly tendered), odd lot priority and conditional tender provisions described in the Offer to Purchase;

6.Mannatech will return at its expense all Shares it does not purchase, including Shares not purchased because of proration or conditional tenders, promptly following the Expiration Date;

7.Under the circumstances set forth in the Offer to Purchase, Mannatech expressly reserves the right, in its sole discretion, to terminate the Offer at any time and from time to time, upon the occurrence of any of the events set forth in Section 7 of the Offer to Purchase, and to extend the period of time during which the Offer is open and thereby delay acceptance for payment of, and payment for, any Shares by giving oral or written notice of such extension to the Depositary and making a public announcement thereof. During any such extension, all Shares previously tendered and not properly withdrawn will remain subject to the Offer and to the rights of a tendering shareholder to withdraw such shareholder’s Shares;

8.Shareholders who cannot deliver their certificates and all other required documents to the Depositary or complete the procedures for book-entry transfer prior to the Expiration Date may tender their Shares by properly completing and duly executing the Notice of Guaranteed Delivery pursuant to the guaranteed delivery procedures set forth in Section 3 of the Offer to Purchase;

9.Mannatech has advised the undersigned to consult with the undersigned’s own advisors as to the consequences of tendering Shares pursuant to the Offer; and

10.THE OFFER IS NOT BEING MADE TO (NOR WILL TENDERS OF SHARES BE ACCEPTED FROM OR ON BEHALF OF) HOLDERS IN ANY JURISDICTION IN WHICH THE MAKING OR ACCEPTANCE OF THE OFFER WOULD NOT BE IN COMPLIANCE WITH THE LAWS OF THAT JURISDICTION.

The undersigned agrees to all of the terms and conditions of the Offer.

Unless otherwise indicated below in the section captioned “Special Issuance Instructions,” please issue the check for payment of the purchase price and/or return any certificates for Shares not tendered or accepted for payment in the name(s) of the registered holder(s) appearing under “Description of Shares Tendered.” Similarly, unless otherwise indicated under “Special Delivery Instructions,” please mail the check for payment of the purchase price and/or return any certificates for Shares not tendered or accepted for payment (and accompanying documents, as appropriate) to the address(es) of the registered holder(s) appearing under “Description of Shares Tendered.” In the event that both the “Special Delivery Instructions” and the “Special Issuance Instructions” are completed, please issue the check for payment of the purchase price and/or return any certificates for Shares not tendered or accepted for payment (and any accompanying documents, as appropriate) in the name(s) of, and deliver such check and/or return such certificates (and any accompanying documents, as appropriate) to, the person or persons so indicated. Please credit any Shares tendered herewith by book-entry transfer that are not accepted for payment by crediting the account at the Book-Entry Transfer Facility designated above. Appropriate medallion signature guarantees by an Eligible Institution (as defined in Instruction 1) have been included with respect to Shares for which Special Issuance Instructions have been given. The undersigned recognizes that Mannatech has no obligation pursuant to the “Special Issuance Instructions” to transfer any Shares from the name of the registered holder(s) thereof if Mannatech does not accept for payment any of the Shares.

SPECIAL DELIVERY INSTRUCTIONS
(See Instructions 1, 5, 6 and 7)
Mail:	☐ Check
	☐ Certificate(s) to:
Name:
	(Please Print)
Address:
	(Please Include Zip Code)
	(Taxpayer Identification or Social Security Number)

SPECIAL ISSUANCE INSTRUCTIONS
(See Instructions 1, 5, 6, and 7)
To be completed ONLY if certificates for Shares not tendered or not accepted for payment and/or the check for payment of the purchase price of Shares accepted for payment are to be issued in the name of someone other than the undersigned, or if Shares tendered hereby and delivered by book-entry transfer which are not purchased are to be returned by crediting them to an account at the book-entry transfer facility other than the account designated above.
Issue:	☐ Check
	☐ Certificate(s) to:
Name:
	(Please Print)
Address:
	(Please Include Zip Code)
	(Taxpayer Identification or Social Security Number)
☐ Credit Shares delivered by book-entry transfer and not purchased tot the account set forth below:
Account Number:

IMPORTANT: SHAREHOLDERS SIGN HERE
(also please complete IRS Form W-9 below or appropriate IRS Form W-8)

Signature(s) of Owner(s):

Date:

(Must be signed by registered holder(s) exactly as name(s) appear(s) on stock certificate(s) or by person(s) authorized to become registered holder(s) of stock certificate(s) as evidenced by endorsement or stock powers transmitted herewith. If signed by a trustee, executor, administrator, guardian, attorney-in-fact, officer of a corporation or other person acting in a fiduciary or representative capacity, the full title of the person should be set forth. See Instruction 5).

Name:
	(Please Print)
Capacity (full title):
Address:
	(Please Include Zip Code)
Daytime Area Code and Telephone Number:
(Taxpayer Identification or Social Security Number)

Complete accompanying IRS Form W-9 or appropriate IRS Form W-8.

GUARANTEE OF SIGNATURE(S)

(For use by Eligible Institutions only; see Instructions 1 and 5)

Name of Firm:
		(Please Print)
Address:
	(Include Zip Code)
Authorized Signature:
Name:
	(Please Type or Print)
Area Code and Telephone Number:
Dated: , 2021

NOTE: A notarization by a notary public is not acceptable.

PLACE MEDALLION GUARANTEE IN SPACE BELOW.

INSTRUCTIONS

Forming Part of the Terms and Conditions of the Offer

1. Guarantee of Signatures. No signature guarantee is required on this Letter of Transmittal if (a) this Letter of Transmittal is signed by the registered holder(s) (which term, for purposes of this Instruction 1, includes any participant in the Book-Entry Transfer Facility’s system whose name appears on a security position listing as the owner of the Shares) of Shares tendered herewith, unless such registered holder(s) has (have) completed the section captioned “Special Issuance Instructions” on this Letter of Transmittal or (b) such Shares are tendered for the account of a bank, broker, dealer, credit union, savings association or other entity that is a member in good standing of a Medallion Program approved by the Securities Transfer Agents Association, Inc., including the Securities Transfer Agents Medallion Program, the New York Stock Exchange, Inc. Medallion Signature Program or the Stock Exchange Medallion Program, or is otherwise an “eligible guarantor institution,” as the term is defined in Exchange Act Rule 17Ad-15, each of the foregoing constituting an “Eligible Institution.” In all other cases, all signatures on this Letter of Transmittal must be guaranteed by an Eligible Institution. See Instruction 5. If you have any questions regarding the need for a signature guarantee, please call the Information Agent at (877) 278-4751.

2. Requirements of Tender. This Letter of Transmittal is to be completed by shareholders if either certificates are to be forwarded herewith or, unless an Agent’s Message is utilized, if delivery of Shares is to be made pursuant to the procedures for book-entry transfer set forth in Section 3 of the Offer to Purchase. For a shareholder to validly tender Shares pursuant to the Offer, (a) a Letter of Transmittal, properly completed and duly executed, and the certificate(s) representing the tendered Shares, together with any required signature guarantees, and any other required documents, must be received by the Depositary at its address set forth on the back of this Letter of Transmittal prior to the Expiration Date, (b) a Letter of Transmittal, properly completed and duly executed, together with any required Agent’s Message and any other required documents, must be received by the Depositary at its address set forth on the back of this Letter of Transmittal prior to the Expiration Date and Shares must be delivered pursuant to the procedures for book-entry transfer set forth in this Letter of Transmittal (and a book-entry confirmation must be received by the Depositary) prior to the Expiration Date, or (c) the shareholder must comply with the guaranteed delivery procedures set forth below and in Section 3 of the Offer to Purchase.

Tenders of Shares made pursuant to the Offer may be withdrawn at any time prior to the Expiration Date. If Mannatech extends the Offer beyond that time, tendered Shares may be withdrawn at any time until the extended Expiration Date. Shares that have not previously been accepted by Mannatech for payment may be withdrawn at any time after 12:00 Midnight, New York City time, at the end of Monday, July 26, 2021. To withdraw tendered Shares, shareholders must deliver a written notice of withdrawal to the Depositary within the prescribed time period at the address set forth in this Letter of Transmittal. Any notice of withdrawal must specify the name of the tendering shareholder, the number of Shares to be withdrawn, and the name of the registered holder of the Shares. In addition, if the certificates for Shares to be withdrawn have been delivered or otherwise identified to the Depositary, then, before the release of the certificates, the tendering shareholder must also submit the serial numbers shown on the particular certificates for Shares to be withdrawn and the signature(s) on the notice of withdrawal must be guaranteed by an Eligible Institution (except in the case of Shares tendered by an Eligible Institution). If Shares have been tendered pursuant to the procedures for book-entry transfer, the notice of withdrawal also must specify the name and the number of the account at Book-Entry Transfer Facility to be credited with the withdrawn Shares and otherwise comply with the procedures of that facility. Withdrawals may not be rescinded and any Shares withdrawn will not be properly tendered for purposes of the Offer unless the withdrawn Shares are properly re-tendered prior to the Expiration Date by following the procedures described above.

Shareholders whose certificates for Shares are not immediately available or who cannot deliver their certificates and all other required documents to the Depositary or complete the procedures for book-entry transfer prior to the Expiration Date may tender their Shares by properly completing and duly executing the Notice of Guaranteed Delivery pursuant to the guaranteed delivery procedures set forth in Section 3 of the Offer to Purchase. Pursuant to those procedures, (a) tender must be made by or through an Eligible Institution, (b) a properly completed and duly executed Notice of Guaranteed Delivery, substantially in the form provided by Mannatech, must be received by the Depositary prior to the Expiration Date and (c) the certificates for all tendered Shares in proper form for transfer (or a book-entry confirmation with respect to all such Shares), together with a Letter of Transmittal, properly completed and duly executed, with any required signature guarantees, or, in the case of a book-entry transfer, an Agent’s Message, and any other required documents, must be received by the Depositary, in each case within two trading days after the date of execution of the Notice of Guaranteed Delivery as provided in Section 3 of the Offer to Purchase. A “trading day” is any day on which The Nasdaq Global Select Market is open for business. The term “Agent’s Message” means a message transmitted by the Book-Entry Transfer Facility to, and received by, the Depositary, which states that the Book-Entry Transfer Facility has received an express acknowledgment from the participant in the Book-Entry Transfer Facility tendering the Shares that such participant has received and agrees to be bound by the terms of the Letter of Transmittal and that Mannatech may enforce such agreement against the participant.

THE METHOD OF DELIVERY OF SHARES, THIS LETTER OF TRANSMITTAL AND ANY OTHER REQUIRED DOCUMENTS, INCLUDING DELIVERY THROUGH THE BOOK-ENTRY TRANSFER FACILITY, IS AT THE SOLE ELECTION AND RISK OF THE TENDERING SHAREHOLDER. SHARES, THIS LETTER OF TRANSMITTAL AND ALL OTHER DOCUMENTS WILL BE DEEMED DELIVERED ONLY WHEN ACTUALLY RECEIVED BY THE DEPOSITARY (INCLUDING, IN THE CASE OF A BOOK-ENTRY TRANSFER, BY BOOK-ENTRY CONFIRMATION). IF YOU ELECT TO DELIVER BY MAIL, WE RECOMMEND THAT YOU USE REGISTERED MAIL WITH RETURN RECEIPT REQUESTED, AND THAT YOU PROPERLY INSURE THE DOCUMENTS. IN ALL CASES, YOU SHOULD ALLOW SUFFICIENT TIME TO ENSURE TIMELY DELIVERY.

Except as specifically provided by the Offer to Purchase, no alternative, conditional or contingent tenders will be accepted. No fractional Shares will be purchased. All tendering shareholders, by execution of this Letter of Transmittal, waive any right to receive any notice of the acceptance for payment of their Shares.

3. Inadequate Space. If the space provided in this Letter of Transmittal is inadequate, the certificate numbers and/or the number of Shares should be listed on a separate signed schedule attached hereto.

4. Partial Tenders (Not Applicable to Shareholders Who Tender by Book-Entry Transfer). If fewer than all of the Shares represented by any certificate submitted to the Depositary are to be tendered, fill in the number of Shares that are to be tendered in the box entitled “Description of Shares Tendered.” In any such case, new certificate(s) for the remainder of the Shares that were evidenced by the old certificate(s) will be sent to the registered holder(s), unless otherwise provided in the appropriate box on this Letter of Transmittal, as soon as practicable after the acceptance for payment of, and payment for, the Shares tendered herewith. All Shares represented by certificates delivered to the Depositary will be deemed to have been tendered unless otherwise indicated. All Shares held in book-entry by the tendering shareholder will be deemed to have been tendered unless otherwise indicated.

5. Signatures on Letter of Transmittal, Stock Powers and Endorsements. If this Letter of Transmittal is signed by the registered holder(s) of the Shares tendered hereby, the signature(s) must correspond with the name(s) as written on the face of the certificate(s) without any change or alteration whatsoever.

If any of the Shares tendered hereby are owned of record by two or more joint owners, all such persons must sign this Letter of Transmittal.

If any Shares tendered hereby are registered in different names on several certificates, it will be necessary to complete, sign and submit as many separate Letters of Transmittal as there are different registrations of certificates.

If this Letter of Transmittal or any certificate or stock power is signed by a trustee, executor, administrator, guardian, attorney-in-fact, officer of a corporation or other person acting in a fiduciary or representative capacity, he or she should so indicate when signing and submit proper evidence satisfactory to Mannatech of his or her authority to so act.

If this Letter of Transmittal is signed by the registered owner(s) of the Shares tendered hereby, no endorsements of certificates or separate stock powers are required unless payment of the purchase price is to be made, or certificates for Shares not tendered or accepted for payment are to be issued, to a person other than the registered owner(s). Signatures on any such certificates or stock powers must be guaranteed by an Eligible Institution.

If this Letter of Transmittal is signed by a person other than the registered owner(s) of the Shares tendered hereby, the certificate(s) representing such Shares must be properly endorsed for transfer or accompanied by appropriate stock powers, in either case signed exactly as the name(s) of the registered owner(s) appear(s) on the certificate(s). The signature(s) on any such certificate(s) or stock power(s) must be guaranteed by an Eligible Institution.

6. Stock Transfer Taxes. Mannatech will pay any stock transfer taxes with respect to the transfer and sale of Shares to it pursuant to the Offer. If, however, payment of the purchase price is to be made to, or if Shares not tendered or accepted for payment are to be registered in the name of, any person(s) other than the registered owner(s), or if Shares tendered hereby are registered in the name(s) of any person(s) other than the person(s) signing this Letter of Transmittal, the amount of any stock transfer taxes (whether imposed on the registered owner(s) or such other person(s)) payable on account of the transfer to such person(s) will be deducted from the purchase price unless satisfactory evidence of the payment of such taxes or exemption from the payment of such taxes will need to be submitted with this Letter of Transmittal.

Except as provided in this Instruction 6, it will not be necessary for transfer tax stamps to be affixed to the certificates listed in this Letter of Transmittal.

7. Special Delivery and Issuance Instructions. If a check for the purchase price of any Shares accepted for payment is to be issued in the name of, and/or certificates for any Shares not accepted for payment or not tendered are to be issued in the name of and/or returned to, a person other than the signer of this Letter of Transmittal or if a check is to be sent, and/or such certificates are to be returned, to a person other than the signer of this Letter of Transmittal or to an address other than that shown above, the appropriate boxes on this Letter of Transmittal should be completed.

8. Waiver of Conditions; Irregularities. All questions as to the number of Shares to be accepted, the validity, form, eligibility (including time of receipt) and acceptance for payment of any tender of Shares and the validity (including time of receipt) and form of any notice of withdrawal of tendered Shares will be determined by Mannatech, in its sole discretion, and such determination will be final and binding on all parties absent a finding to the contrary by a court of competent jurisdiction. Mannatech may delegate power in whole or in part to the Depositary. Mannatech reserves the absolute right to reject any or all tenders of any Shares that Mannatech determines are not in proper form or the acceptance for payment of or payment for which may, in the opinion of Mannatech’s counsel, be unlawful. Mannatech reserves the absolute right to reject any notices of withdrawal that it determines are not in proper form. Mannatech also reserves the absolute right, subject to the applicable rules and regulations of the Securities and Exchange Commission, to waive any of the conditions of the Offer prior to the Expiration Date, or any defect or irregularity in any tender or withdrawal with respect to any particular Shares or any particular shareholder (whether or not Mannatech waives similar defects or irregularities in the case of other shareholders), and Mannatech’s interpretation of the terms of the Offer (including these instructions) will be final and binding on all parties absent a finding to the contrary by a court of competent jurisdiction. In the event a condition is waived with respect to any particular shareholder, the same condition will be waived with respect to all shareholders. No tender or withdrawal of Shares will be deemed to have been properly made until all defects or irregularities have been cured by the tendering or withdrawing shareholder or waived by Mannatech. Mannatech will not be liable for failure to waive any condition of the Offer, or any defect or irregularity in any tender or withdrawal of Shares. Unless waived, any defects or irregularities in connection with tenders or withdrawals must be cured within the period of time Mannatech determines. None of Mannatech, the Dealer Manager, the Information Agent, the Depositary or any other person will be obligated to give notice of any defects or irregularities in any tender or withdrawal, nor will any of the foregoing incur any liability for failure to give any such notification.

9. Backup Withholding. In order to avoid backup withholding of U.S. federal income tax on payments of cash pursuant to the Offer, a U.S. Holder (as defined below) tendering Shares in the Offer must (a) qualify for an exemption, as described below, or (b) provide the Depositary or other applicable withholding agent with such U.S. Holder’s correct taxpayer identification number (“TIN”) (i.e., social security number or employer identification number) on IRS Form W-9, a copy of which is included with this Letter of Transmittal, and certify under penalties of perjury that (i) the TIN provided is correct, (ii) (x) the U.S. Holder is exempt from backup withholding, (y) the U.S. Holder has not been notified by the Internal Revenue Service (the “IRS”) that such U.S. Holder is subject to backup withholding as a result of a failure to report all interest or dividends, or (z) the IRS has notified the U.S. Holder that such U.S. Holder is no longer subject to backup withholding, and (iii) the U.S. Holder is a U.S. person (including a U.S. resident alien). If a U.S. Holder does not provide a correct TIN or fails to provide the certifications described above, the IRS may impose a $50 penalty on such U.S. Holder and payment of cash to such U.S. Holder pursuant to the Offer may be subject to backup withholding at the applicable statutory rate (currently 24%).

A “U.S. Holder” is any shareholder that for U.S. federal income tax purposes is (i) a citizen or resident of the United States, including an alien individual who is a lawful permanent resident of the United States or meets the “substantial presence” test under Section 7701(b) of the Code, (ii) a corporation or partnership created or organized in or under the laws of the United States, any state thereof or the District of Columbia, (iii) an estate, the income of which is subject to U.S. federal income taxation regardless of its source, or (iv) a trust, if a court within the United States is able to exercise primary supervision over the administration of the trust and one or more “United States persons” within the meaning of Section 7701(a)(30) of the Code have the authority to control all substantial decisions of the trust, or, if the trust was in existence on August 20, 1996, and it has elected to continue to be treated as a United States person.

Backup withholding is not an additional tax. Rather, the amount of the backup withholding can be credited against the U.S. federal income tax liability of the person subject to the backup withholding, provided that the required information is timely given to the IRS. If backup withholding results in an overpayment of tax, a refund can be obtained upon timely filing an income tax return.

A tendering U.S. Holder is required to give the Depositary or other applicable withholding agent the TIN of the record owner of the Shares being tendered. If the Shares are held in more than one name or are not in the name of the actual owner, consult the instructions to the enclosed IRS Form W-9 for guidance on which number to report.

If a U.S. Holder has not been issued a TIN and has applied for one or intends to apply for one in the near future, such U.S. Holder should write “Applied For” in the space provided for the TIN in Part I of the IRS Form W-9, and sign and date the IRS

Form W-9. Writing “Applied For” means that a U.S. Holder has already applied for a TIN or that such U.S. Holder intends to apply for one soon. Notwithstanding that the U.S. Holder has written “Applied For” in Part I, the Depositary will withhold the applicable statutory rate (currently 24%) on all payments made prior to the time a properly certified TIN is provided to the Depositary.

Some shareholders are exempt from backup withholding. To prevent possible erroneous backup withholding, exempt shareholders should consult the instructions to the enclosed IRS Form W-9 for additional guidance.

Non-U.S. Holders (as defined below) should complete and sign the main signature form and IRS Form W-8BEN or W-8BEN-E (or other applicable IRS Form W-8) in order to avoid backup withholding. A copy of the appropriate IRS Form W-8 may be obtained from the Depositary or from the IRS website (www.irs.gov). A “Non-U.S. Holder” is a shareholder that is not a U.S. Holder. A disregarded domestic entity that has a foreign owner must use the appropriate IRS Form W-8, and not the IRS Form W-9. See the instructions to the enclosed IRS Form W-9 for more instructions.

10. Withholding on Non-U.S. Holders. Non-U.S. shareholders, such as non-resident alien individuals and foreign entities, including a disregarded U.S. domestic entity that has a foreign owner, should not complete an IRS Form W-9.

If you are a Non-U.S. Holder, because it is unclear whether the cash you receive in connection with the Offer will be treated (i) as proceeds of a sale or exchange or (ii) as a distribution, the Depositary or other applicable withholding agent may treat such payment as a dividend distribution for U.S. federal withholding tax purposes. Accordingly, if you are a Non-U.S. Holder, you may be subject to withholding on payments to you at a rate of 30% of the gross proceeds paid, unless the Depositary or other applicable withholding agent determines that a reduced rate of withholding is available pursuant to a tax treaty or that an exemption from withholding is applicable because such gross proceeds are effectively connected with your conduct of a trade or business within the United States. See Section 13 of the Offer to Purchase. In order to obtain a reduced rate of withholding pursuant to an applicable income tax treaty, a Non-U.S. Holder must deliver to the Depositary or other applicable withholding agent, before the payment is made, a properly completed and executed IRS Form W-8BEN or W-8BEN-E claiming such a reduction. In order to claim an exemption from withholding on the grounds that the gross proceeds paid pursuant to the Offer are effectively connected with the conduct of a trade or business within the United States, a Non-U.S. Holder must deliver to the Depositary or other applicable withholding agent, before the payment is made, a properly completed and executed IRS Form W-8ECI. A Non-U.S. Holder may be eligible to obtain a refund of all or a portion of any U.S. federal tax withheld if such Non-U.S. Holder meets the “complete termination,” “substantially disproportionate” or “not essentially equivalent to a dividend” tests described in Section 13 of the Offer to Purchase or is otherwise able to establish that such Non-U.S. Holder is entitled to a reduced rate of withholding pursuant to any applicable income tax treaty and a higher rate was withheld.

Under Sections 1471 through 1474 of the Code, commonly referred to as “FATCA,” and related administrative guidance, a United States federal withholding tax of 30% generally will be imposed on dividends that are paid to “foreign financial institutions” and “non-financial foreign entities” (as specifically defined under these rules), whether such institutions or entities hold Shares as beneficial owners or intermediaries, unless specified requirements are met. Because, as discussed above, the Depositary or other applicable withholding agent may treat amounts paid to Non-U.S. Holders in the Offer as dividend distributions for U.S. federal withholding tax purposes, such amounts may also be subject to withholding under FATCA if such requirements are not met. In such case, any withholding under FATCA may be credited against, and therefore reduce, any 30% withholding tax on dividend distributions as discussed above. Non-U.S. Holders should consult with their tax advisors regarding the possible implications of these rules on their disposition of Shares pursuant to the Offer.

NON-U.S. HOLDERS ARE URGED TO CONSULT THEIR OWN TAX ADVISORS REGARDING THE APPLICATION OF THE U.S. FEDERAL INCOME TAX WITHHOLDING RULES, INCLUDING ELIGIBILITY FOR A WITHHOLDING TAX REDUCTION OR EXEMPTION, AND THE REFUND PROCEDURE, AS WELL AS THE APPLICABILITY AND EFFECT OF STATE, LOCAL, FOREIGN AND OTHER TAX LAWS.

Any payments made pursuant to the Offer, whether to U.S. or Non-U.S. Holders, that are treated as wages will be subject to applicable wage withholding (regardless of whether an IRS Form W-9 or applicable IRS Form W-8 is provided).

11. Requests for Assistance or Additional Copies. If you have questions or need assistance, you should contact the Information Agent or the Dealer Manager at their respective addresses and telephone numbers set forth on the back cover of this Letter of Transmittal. If you require additional copies of the Offer to Purchase, this Letter of Transmittal, the Notice of Guaranteed Delivery, the IRS Form W-9 or other related materials, you should contact the Information Agent. Copies will be furnished promptly at Mannatech’s expense.

12. Lost, Destroyed or Stolen Certificates. If any certificate representing Shares has been lost, destroyed or stolen, the shareholder should promptly notify the Depositary at (877) 373-6374. The shareholder will then be instructed by the Depositary as to the steps that must be taken in order to replace the certificate. This Letter of Transmittal and related documents cannot be processed until the procedures for replacing lost, destroyed or stolen certificates have been followed.

13. Conditional Tenders. As described in Sections 3 and 6 of the Offer to Purchase, shareholders may condition their tenders on all or a minimum number of their tendered Shares being purchased.

If you wish to make a conditional tender you must indicate this in the box captioned “Conditional Tender” in this Letter of Transmittal and, if applicable, the Notice of Guaranteed Delivery. In this box in this Letter of Transmittal and, if applicable, the Notice of Guaranteed Delivery, you must calculate and appropriately indicate the minimum number of Shares that must be purchased if any are to be purchased.

As discussed in Sections 3 and 6 of the Offer to Purchase, proration may affect whether Mannatech accepts conditional tenders and may result in Shares tendered pursuant to a conditional tender being deemed withdrawn if the minimum number of Shares would not be purchased. Upon the terms and subject to the conditions of the Offer, if, because of proration (because more than the number of Shares sought are properly tendered), the minimum number of Shares that you designate will not be purchased, Mannatech may accept conditional tenders made at or below the Final Purchase Price by random lot, if necessary. However, to be eligible for purchase by random lot, you must have tendered all of your Shares and check the box so indicating. Upon selection by lot, if any, Mannatech will limit its purchase in each case to the designated minimum number of Shares.

All tendered Shares will be deemed unconditionally tendered unless the “Conditional Tender” box is completed. If you are an Odd Lot Holder (defined below) and you tender all of your Shares, you cannot conditionally tender, since your Shares will not be subject to proration. Each shareholder is urged to consult his, her or its own tax advisor.

The conditional tender alternative is made available so that a shareholder may seek to structure the purchase of Shares pursuant to the Offer in such a manner that the purchase will be treated as a sale of such Shares by the shareholder, rather than the payment of a dividend to the shareholder, for U.S. federal income tax purposes. It is the tendering shareholder’s responsibility to calculate the minimum number of Shares that must be purchased from the shareholder in order for the shareholder to qualify for sale rather than dividend treatment. Each shareholder is urged to consult his or her own tax advisor. See Section 6 of the Offer to Purchase.

14. Order of Purchase in Event of Proration. As described in Section 1 of the Offer to Purchase, shareholders may designate the order in which their Shares are to be purchased in the event of proration. The order of purchase may have an effect on the U.S. federal income tax classification and the amount of any gain or loss on the Shares purchased. See Section 1 and Section 13 of the Offer to Purchase.

15. Odd Lots. As described in Section 1 of the Offer to Purchase, any person who owns, beneficially or of record, a total of fewer than 100 Shares (“Odd Lot Holder”), will have their Shares accepted for payment before any proration of or purchase of any other tendered Shares (the “Odd Lot Priority”).

If the Company purchases less than all Shares tendered and not withdrawn before the Expiration Date, the Shares purchased first will consist of all Shares tendered by any Odd Lot Holder who elects to take the Odd Lot Priority by completing the box captioned “Odd Lots” in this Letter of Transmittal and, if applicable, in the Notice of Guaranteed Delivery.

Even if you otherwise qualify for the Odd Lot Priority, you will not receive such preferential treatment unless you affirmatively elect to take it in this Letter of Transmittal and, if applicable, in the Notice of Guaranteed Delivery.

IMPORTANT: THIS LETTER OF TRANSMITTAL, TOGETHER WITH ANY REQUIRED SIGNATURE GUARANTEES, OR, IN THE CASE OF A BOOK-ENTRY TRANSFER, AN AGENT’S MESSAGE, AND ANY OTHER REQUIRED DOCUMENTS, MUST BE RECEIVED BY THE DEPOSITARY PRIOR TO THE EXPIRATION DATE AND EITHER CERTIFICATES FOR TENDERED SHARES MUST BE RECEIVED BY THE DEPOSITARY OR SHARES MUST BE DELIVERED PURSUANT TO THE PROCEDURES FOR BOOK-ENTRY TRANSFER, IN EACH CASE PRIOR TO THE EXPIRATION DATE, OR THE TENDERING SHAREHOLDER MUST COMPLY WITH THE PROCEDURES FOR GUARANTEED DELIVERY.

Any questions or requests for assistance may be directed to the Information Agent or the Dealer Manager at their respective telephone numbers and addresses set forth below. Requests for additional copies of the Offer to Purchase, this Letter of Transmittal, the Notice of Guaranteed Delivery or related documents may be directed to the Information Agent at its telephone number or address set forth below. You may also contact your broker, dealer, commercial bank, trust company or other nominee for assistance concerning the Offer.

The Depositary for the Offer is:

Computershare Trust Company, N.A.

c/o Voluntary Corporate Actions

150 Royall Street, Suite V

Canton MA 02021

Computershare Trust Company, N.A.

c/o Voluntary Corporate Actions

P.O. Box 43011

Providence, RI 02940-3011

The Information Agent for the Offer is:

 Georgeson LLC.

1290 Avenue of the Americas, 9th Floor

New York, New York 10104

Call: (877) 278-4751

The Dealer Manager for the Offer is:

1290 Avenue of the Americas, 9th Floor

New York, New York 10104

Call: (212) 440-9850