Here is a link to a great article in the New York Times written 11/30/06 titled "The Thing About Retin A, It Works". Article states that Retin A and retinol are the only active ingredients that are proven to work.

Another great article in the L.A.Times written 03/18/07 titled "Hype Springs Eternal". The article again states that retinol is the only over the counter active ingredient that works.