I was just given a subtle sales pitch from my mother's friend—she exhibited several red flags which I decided should be recorded here for other people to better understand what sorts of common warning signs they might notice.
She kept talking about “the product” without actually saying what it was or what it did.
She appealed to the common desire for supplemental income and financial independence, while emphasizing the ease and rapidity with which such wealth can be expected. (A.k.a. “get rich quick”.)
These first two notes indicated that this is a multilevel marketing company (trying to rebrand itself as a network marketing company), looking at their wikipedia page it seems they've changed their name a few times in the past, also a warning sign. (Good brands don't change their names because they lose brand recognition, bad brands change their names with the intent of losing negative brand recognition. E.g. Academi, formerly Xe Services LLC, formerly Blackwater.)
She said twice that they've performed these same experiments on dogs and other animals, and that, “animals don't lie,” as if this were stronger evidence than say a double blind study.
The word “natural” was used as an implicit synonym for the word “good,” while (in other conversations the day before), the word “chemical” was implicitly synonymous with “bad”.
In general the supplement industry behaves deplorably, preying on people's desperation for improving their health or prolonging their lives, and the multilevel marketing world is comparably deplorable, preying on people's desperation for financial stability.
It is suggested that these products benefit the aging process, the sort of claim you might expect from a snake oil salesman. Rationality means to proportion one's belief to the evidence in support of a fact, summarized in the adage, “extraordinary claims require extraordinary evidence”. The evidence LifeVantage presents in support of their claims does not hold up. I suspect part of their strategy is to use any scientific study that does not paint their product in a negative light to give the impression that it is supported by a substantial body of research, but looking at the actual studies they simply don't support the extraordinary claims.