Some of these are synthetic but most are compounds discovered from some sort of natural source, like a rare melon that is grown only in France or an even rarer orchid found only in a mysterious jungle somewhere. Of course the more rare the plant, the more expensive the product, which only increases the hype about it. Most of these substances are animated by the marketing hype about them, which points to the unfortunate fact that few if any of them actually undergo serious scientific research and clinical testing. Most are like a flash in the pan, and as the media hype-wave passes, the substance recedes from memory in perfect timing with the arrival of the next new miracle substance promising miracle skin rejuvenation.
On the other hand, a few of these substances actually do work, and some have been around long enough that scientific studies have validated some of the claims made in the media. One such substance is Alpha Lipoic Acid. Alpha Lipoic Acid benefits not only you skin but has many other important roles.