In radio ads, the company offers a guarantee of of improved grades or your money back. Written policy posted on web site (not seen by me before purchase over the phone) is for a 32-day money-back guarantee. However, I was told over the phone that they would take the product back unopened after the 32-day window. Return period window begins on date of order, NOT date of receipt, so you have about three weeks to try it. If you call them during the return window period, however, they attempt to convince you to give the product more time to work... read full review »