Unfortunately, not all sex enhancement supplement manufacturers are conscientious, which is why the US FDA has to make so many public notifications every year, warning the public of certain sex enhancers that are tainted, adulterated, and generally unsafe.
If you happen to drop by at a gas station, take the time to check out all the sex enhancement products that are on display and available for sale to anyone who is looking for an instant sexual performance upgrade.
Some of those products may work to some extent, but probably not as well as advertised. Many sex enhancers sold at gas stations are advertised as something that can increase your sexual stamina or give you extremely hard erections.
And yet, many of these products are sold in single-pill packages. Before you buy one, remember that even sildenafil, the most time-tested and scientifically proven medicine for erectile dysfunction, takes several days of regular intake before the effects start showing.
To answer the question, there are many sex enhancers that do not work as advertised. If you plan to use a sex enhancement supplement, you need to be careful about which one you will purchase. That being said, there are several supplements for sexual enhancement that actually work, are legit, and not a scam at all.