I used Revivogen for one year and four months, in conjunction with no other products, and although I'm only one case, I'm unhappy to report that it didn't work for me: which is to say that it didn't re-grow any hair, neither in my crown or at my temples.
Now, Revivogen is a product which has a lot of ingredients in it. The makers of Revivogen have basically just taken whatever has seemed remotely effective and tossed it into a stable-base product. So, even if Revivogen worked for some people, which I doubt (unless of course they also used minoxidil and/or Propecia, etc.) it may not be attributable solely to the fatty acids found in it.
O.
P.S. Also, I don't use Revivogen shampoo, as I stated below, to in any way re-grow hair. I just think it's a good shampoo that makes my hair look nice... Maybe that's the only benefit of fatty acids.