In yesteryear, patent medicines were supposed to treat specific ailments (though the number of specific ailments they claimed to treat was extensive). Nowadays we have "herbal supplements" which fill the market niche of poorly-regulated non-foods making bogus health claims.
The difference is that these things tend to promote general wellness over long periods instead of claiming to fix specific issues.
Which is really a better way to secure a customer base than the old patent medicines had. With Patent Medicine you use it and see pretty quickly if it works, and if you're not the kind of person to make excuses or be fooled by false hope, you throw the stuff away and never buy it again. A Snake-Oil Salesman always has to look for new customers who don't know that the product is defective.
Herbal Supplements, by contrast, make vague long-term claims that can only be tested over months and years, and the usual customer isn't paying much attention for that long. Maybe they realize after a year that they aren't feeling better, but in the meantime they've been buying the product for a whole year, and the more gullible customers will think that any improvement in health, from any source over that year, comes from the supplements. It's perfect! You can throw anything in a bottle and the suckers will keep buying it!
And even better, if the customer doesn't get better then you can blame them for living an unhealthy lifestyle. It's like advertising kid's cereal as "part of this balanced breakfast" where you show the box next to a plate of eggs and toast. Claims of Herbal Supplements are much more difficult to falsify than patent medicines ever were.
Especially since they don't kill their customers nearly as often.