I'm sure a few products out there are scams, but speaking from my own experience/anecdotes I think the real ones do actually work. Specifically the products containing androstenone, androsterone, and the other related endogenous steroid hormones.

I used some (from Amazon, forget the brand) on my neck and my wife literally would not stop hugging me and telling me how great I smelled. She's actually initiated sex a few times after I've applied it.