officially. i've made it clear that i wasn't going to do that. are you trying to get me to endorse the product? i'm not going to do it. >> reporter: i'm not trying to get you to endorse it. i'm trying to get you to answer a question -- >> i'm just telling you that personality, i have found nutritional supplements to be good. >> reporter: yeah, and are you concerned at all that there is no clinically proven study that says -- >> i do not endorse it for anybody else except for me. >> reporter: dr. carson, thanks, good luck to you. >> drew griffin joins us. he says he not only does he used product but his mom does, as well. >> she suffers from alzheimer's since 2011 and she takes it. i said does it work for her? he says it seems to. >> how can he claim, though, like he did in the cnbc debate that there is no relationship with mannatech? he gave repeated speeches. they under wrote something he did on public broadcasting a special under by associates of the company. it sure sounds like a relationship, i guess, is the