Sustain dba Today The World LLC, offers a 100% money back guarantee on “Sustain” purchased on this website. Conditions for guarantee: Customer must not have used more than 4 capsules out of one box of 10 capsules to receive a complete refund at the purchase price. All product must be returned within 30 days of original purchase date. If customer has used more than 4 capsules out of open box, no refund will be given.There are no conditions or expectations to qualify for the guarantee. If you are not completely happy with the results, you may email or call us for return merchandise authorization and upon receipt of your return, we will issue a full refund.