As a scientist with the American Red Cross, Fahy was the originator of the first practical method of cryopreservation by vitrification and the inventor of computer-based systems to apply this technology to whole organs. Before joining Twenty-First Century Medicine, he was the chief scientist for Organ, Inc and of LRT, Inc. He was also Head of the Tissue Cryopreservation Section of the Transfusion and Cryopreservation Research Program of the U.S. Naval Medical Research Institute in Bethesda, Maryland where he spearheaded the original concept of ice blocking agents. In 2014, he was named a Fellow of the Society for Cryobiology in recognition of the impact of his work in low temperature biology.
In 2015–2017, Fahy led the TRIIM (Thymus Regeneration, Immunorestoration, and Insulin Mitigation) human clinical trial, designed to reverse aspects of human aging. The purpose of the TRIIM trial was to investigate the possibility of using recombinant human growth hormone (rhGH) to prevent or reverse signs of immunosenescence in ten 51‐ to 65‐year‐old putatively healthy men. The study: