Here is a round up of the current contenders for slowing or reducing aging. As research continues, and if/when they make real advancements in human trials (or at least human cells) I'll split them into their own pages with more analysis.

Metformin

Diabetics who are on metformin actually seem to be living longer than nondiabetics who are not on it - Bill Gifford

David Sinclair has said he is taking it - but skips the pill on days that he exercises.

Radiation Hormesis

Non-sanctioned therapy used by athritis sufferers.

The Therapeutic use of Radon: A Biomedical Treatment in Europe; An “Alternative” Remedy in the United States - National Center for Biotechnology Information - 23-Sep-2006
Discusses the decision-making process involved in using radon, and compare the Montana radon health mine facilities with selected radon mines and spas in Europe.

Rapamycin (aka sirolimus)

A chemical produced by bacteria that has been shown to have immunosuppressive and antiproliferative properties. It is currently used in the prevention of transplant rejection and as a coronary stent coating, and is also being tested for certain cancers.