The general publics interest in healthier lifestyles, healthier aging and disease prevention

EXHIBIT 10.15

PROMISSORY NOTE

Principal

Loan Date

Maturity

Loan No.

Officer

$500,000.00

10-22-2008

10-22-2009

6824

Call/Coll

Account

BLD

Initials

References in the boxes above are for Lender’s use only and do not limit the applicability of this document to any particular loan or item. Any item above containing “***” has been omitted due to text length limitations.

Borrower:		RBC Life Sciences USA, Inc.		Lender:		Independent Bank of Texas
		2301 Crown Court				Independent Bank of Texas — Irving
		Irving, TX 75038-4305				P. O. Box 167099
						Irving, TX 75016
						(972)  ###-###-####

Principal Amount: $500,000.00		Date of Note: October 22, 2008

PROMISE TO PAY. RBC Life Sciences USA, Inc. (“Borrower”) promises to pay to Independent Bank of Texas (“Lender”), or order, in lawful money of the United Stales of America, the principal amount of Five Hundred Thousand & 00/100 Dollars ($500,000.00) or so much as may be outstanding, together with interest on the unpaid outstanding principal balance of each advance, calculated as described in the “INTEREST CALCULATION METHOD” paragraph using an interest rate of 5.050% per annum based on a year of 360 days. Interest shall be calculated from the date of each advance until repayment of each advance or maturity, whichever occurs first. The interest rate may change under the terms and conditions of the “POST MATURITY RATE” section.

CHOICE OF USURY CEILING AND INTEREST RATE. The interest rate on this Note has been implemented under the “Weekly Ceiling” as referred to in Sections 303.002 and 303.003 of the Texas Finance Code. However, Lender reserves the right to implement a different interest rate and to renew such rate, provided Lender complies with the requirements of Sections 303.101, 102 and 103 of the Texas Finance Code.

PAYMENT. Borrower will pay this loan in full immediately upon Lender’s demand. If no demand is made, Borrower will pay this loan in one payment of all outstanding principal plus all accrued unpaid interest on October 22, 2009. In addition, Borrower will pay regular monthly payments of all accrued unpaid interest due as of each payment date, beginning November 22, 2008, with all subsequent interest payments to be due on the same day of each month after that. Unless otherwise agreed or required by applicable law, payments will be applied first to any accrued unpaid interest; then to principal; and then to any unpaid collection costs. Borrower will pay Lender at Lender’s address shown above or at such other place as Lender may designate in writing. Notwithstanding any other provision of this Note, Lender will not charge interest on any undisbursed loan proceeds. No scheduled payment, whether of principal or interest or both, will be due unless sufficient loan funds have been disbursed by the scheduled payment date to justify the payment.

MAXIMUM INTEREST RATE. Under no circumstances will the interest rate on this Note exceed (except for any higher default rate shown below) the lesser of 18.000% per annum or the maximum rate allowed by applicable law.

INTEREST CALCULATION METHOD. Interest on this Note is computed on a 365/360 basis; that is, by applying the ratio of the interest rate over a year of 360 days, multiplied by the outstanding principal balance, multiplied by the actual number of days the principal balance is outstanding, unless such calculation would result in a usurious rate, in which case interest shall be calculated on a per diem basis of a year of 365 or 366 days, as the case may be. All interest payable under this Note is computed using this method. This calculation method results in a higher effective interest rate than the numeric interest rate stated in this Note. (Initial here SEB)

PREPAYMENT. Borrower may pay without penalty all or a portion of the amount owed earlier than it is due. Prepayment in full shall consist of payment of the remaining unpaid principal balance together with all accrued and unpaid interest and all other amounts, costs and expenses for which Borrower is responsible under this Note or any other agreement with Lender pertaining to this loan, and in no event will Borrower ever be required to pay any unearned interest. Early payments will not, unless agreed to by Lender in writing, relieve Borrower of Borrower’s obligation to continue to make payments of accrued unpaid interest. Rather, early payments will reduce the principal balance due. Borrower agrees not to send Lender payments marked “paid in full”, “without recourse”, or similar language. If Borrower sends such a payment, Lender may accept it without losing any of Lender’s rights under this Note, and Borrower will remain obligated to pay any further amount owed to Lender. All written communications concerning disputed amounts, including any check or other payment instrument that indicates that the payment constitutes “payment in full” of the amount owed or that is tendered with other conditions or limitations or as full satisfaction of a disputed amount must be mailed or delivered to: Independent Bank of Texas, P. O. Box 167099, Irving, TX 75016-7099.

PROMISSORY NOTE

Loan No: 6824		(Continued)		Page 2

POST MATURITY RATE. The Post Maturity Rate on this Note is the lesser of (A) the maximum rate allowed by law or (B) 18.000% per annum based on a year of 360 days. Borrower will pay interest on all sums due after final maturity, whether by acceleration or otherwise, at that rate.

LENDER’S RIGHTS. Upon default, Lender may declare the entire indebtedness, including the unpaid principal balance under this Note, all accrued unpaid interest, and all other amounts, costs and expenses for which Borrower is responsible under this Note or any other agreement with Lender pertaining to this loan, immediately due, without notice, and then Borrower will pay that amount.

ATTORNEYS’ FEES; EXPENSES. Lender may hire an attorney to help collect this Note if Borrower does not pay, and Borrower will pay Lender’s reasonable attorneys’ fees. Borrower also will pay Lender all other amounts Lender actually incurs as court costs, lawful fees for filing, recording, releasing to any public office any instrument securing this Note; the reasonable cost actually expended for repossessing, storing, preparing for sale, and selling any security; and fees for noting a lien on or transferring a certificate of title to any motor vehicle offered as security for this Note, or premiums or identifiable charges received in connection with the sale of authorized insurance.

GOVERNING LAW. This Note will be governed by federal law applicable to Lender and, to the extent not preempted by federal law, the laws of the State of Texas without regard to its conflicts of law provisions. This Note has been accepted by Lender in the State of Texas.

CHOICE OF VENUE. If there is a lawsuit, and if the transaction evidenced by this Note occurred in Dallas County, Borrower agrees upon Lender’s request to submit to the jurisdiction of the courts of Dallas County, State of Texas.

DISHONORED CHECK CHARGE. Borrower will pay a processing fee of $25.00 if any check given by Borrower to Lender as a prepayment on this loan is dishonored.

RIGHT OF SETOFF. To the extent permitted by applicable law, Lender reserves a right of setoff in all Borrower’s accounts with Lender (whether checking, savings, or some other account). This includes all accounts Borrower holds jointly with someone else and all accounts Borrower may open in the future. However, this does not include any IRA or Keogh accounts, or any trust accounts for which setoff would be prohibited by law. Borrower authorizes Lender, to the extent permitted by applicable law, to charge or setoff all sums owing on the indebtedness against any and all such accounts.

LINE OF CREDIT. This Note evidences a revolving line of credit. Advances under this Note, may be requested orally by Borrower or as provided in this paragraph. All oral requests shall be confirmed in writing on the day of the request. All communications, instructions, or directions by telephone or otherwise to Lender are to be directed to Lender’s office shown above. Borrower agrees to be liable for at sums either: (A) advanced in accordance with the instructions of an authorized person or (B) credited to any of Borrower’s accounts with Lender. The unpaid principal balance owing on this Note at any time may be evidenced by endorsements on this Note or by Lender’s internal records, including daily computer print-outs. Lender will have no obligation to advance funds under this Note if: (A) Borrower or any guarantor is in default under the terms of this Note or any agreement that Borrower or any guarantor has with Lender, including any agreement made in connection with the signing of this Note; (B) Borrower or any guarantor ceases doing business or is insolvent; (C) any guarantor seeks, claims or otherwise attempts to limit, modify or revoke such guarantor’s guarantee of this Note or any other loan with Lender; or (D) Borrower has applied funds provided pursuant to this Note for purposes other than those authorized by Lender; or (E) Lender in good faith believes itself insecure. This revolving line of credit shall not be subject to Ch. 346 of the Texas Finance Code.

RENEWAL AND EXTENSION. This Note is given in renewal and extension and not in novation of the following described indebtedness: NOTE #6824.

PROMISSORY NOTE

Loan No: 6824		(Continued)		Page 3

SUCCESSOR INTERESTS. The terms of this Note shall be binding upon Borrower, and upon Borrower’s heirs, personal representatives, successors and assigns, and shall inure to the benefit of Lender and its successors and assigns.

GENERAL PROVISIONS. NOTICE: Under no circumstances (and notwithstanding any other provisions of this Note) shall the interest charged, collected, or contracted for on this Note exceed the maximum rate permitted by law. The term “maximum rate permitted by law” as used in this Note means the greater of (a) the maximum rate of interest permitted under federal law or other law applicable to the indebtedness evidenced by this Note, or (b) the higher, as of the date of this Note, of the “Weekly Ceiling” or the “Quarterly Ceiling” as referred to in Sections 303.002, 303.003 and 303.006 of the Texas Finance Code. If any part of this Note cannot be enforced, this fact will not affect the rest of the Note. Borrower does not agree or intend to pay, and Lender does not agree or intend to contract for, charge, collect, take, reserve or receive (collectively referred to herein as “charge or collect”), any amount in the nature of interest or in the nature of a fee for this loan, which would in any way or event (including demand, prepayment, or acceleration) cause Lender to charge or collect more for this loan than the maximum Lender would be permitted to charge or collect by federal law or the law of the State of Texas (as applicable). Any such excess interest or unauthorized fee shall, instead of anything stated to the contrary, be applied first to reduce the principal balance of this loan, and when the principal has been paid in full, be refunded to Borrower. The right to accelerate maturity of sums due under this Note does not include the right to accelerate any interest which has not otherwise accrued on the date of such acceleration, and Lender does not intend to charge or collect any unearned interest in the event of acceleration. All sums paid or agreed to be paid to Lender for the use, forbearance or detention of sums due hereunder shall, to the extent permitted by applicable law, be amortized, prorated, allocated and spread throughout the full term of the loan evidenced by this Note until payment in full so that the rate or amount of interest on account of the loan evidenced hereby does not exceed the applicable usury ceiling. Lender may delay or forgo enforcing any of its rights or remedies under this Note without losing them. Borrower and any other person who signs, guarantees or endorses this Note, to the extent allowed by law, waive presentment, demand for payment, notice of dishonor, notice of intent to accelerate the maturity of this Note, and notice of acceleration of the maturity of this Note. Upon any change in the terms of this Note, and unless otherwise expressly stated in writing, no party who signs this Note, whether as maker, guarantor, accommodation maker or endorser, shall be released from liability. All such parties agree that Lender may renew or extend (repeatedly and for any length of time) this loan or release any party or guarantor or collateral; or impair, fail to realize upon or perfect Lender’s security interest in the collateral without the consent of or notice to anyone. All such parties also agree that Lender may modify this loan without the consent of or notice to anyone other than the party with whom the modification is made. The obligations under this Note are joint and several.

PRIOR TO SIGNING THIS NOTE, BORROWER READ AND UNDERSTOOD ALL THE PROVISIONS OF THIS NOTE. BORROWER AGREES TO THE TERMS OF THE NOTE.

BORROWER ACKNOWLEDGES RECEIPT OF A COMPLETED COPY OF THIS PROMISSORY NOTE.

BORROWER:

RBC LIFE SCIENCES USA, INC.
By:		/s/ Steven E Brown   Steven E. Brown, Vice President, CFO of
		RBC Life Sciences USA, Inc.