Zicam has a particularly excellent business model: you are directed to use their product every few hours as soon as you think that maybe you sorta kinda have a cold, until you're completely over it or are sure you don't have one. When you didn't actually get a cold, it worked! And if you did get a cold, just think of how much worse it could have been!
It's kind of like selling volcano insurance, or perhaps a magical device that wards off tikbalangs. Wouldn't want to be attacked by tikbalangs. They sound scary.
It's even an unpleasant product. The first version I tried was sold as sticky, goo-covered swabs that you stuck in your nose and swiped around. Those were just too nasty to bear, so now I'm trying the citrus-flavored pellets. Calling the flavor "citrus" is kind of a stretch, though. If I had to assign words to the flavor, I'd pick "ground up dead people." That's why I'm not in marketing.