BtoBonline:

"Our experience is that dialogue and entertainment-based content are
the most effective" way to induce word-of-mouth, said Darren Paul,
managing partner at Night Agency, a New York-based interactive shop
that created Safety Town.

If you sell a product that helps people with joint pain, talk to people with joint pain. Be up front. Tell them that you are a rep. for a company that has an excellent product and then give them a sample.