On Wednesday, the FDA issued six alerts for male sexual enhancement products that contained potentially harmful ingredients, with no mention of them on the actual product. These alerts were added to the list of many, many other sexual enhancement products that contain hidden prescription drug ingredients.

Some of the products they analyzed actually contained tadalafil, the active ingredient in Cialis. Other products contained drugs that were structurally similar to tadalafil or sildenafil, the active ingredient in Viagra. Not to mention all those "natural" ingredients on the label, which are untested, unstudied, and definitely not FDA-approved.

"It's been known for quite a number of years that male supplements have included chemicals within them that are either normally prescription medicines like generic forms of Viagra or Cialis or [are] tainted in some cases with things that don’t belong there, like heavy metals and things like that," Dr. Abraham Morgentaler, director of Men’s Health Boston, clinical professor at Harvard Medical School, tells BuzzFeed Health.