Findings published in the journal Aging Cell describes combined efforts to investigate the impact of rhGH on the thymus. Interested in this impact began in 1986 when injecting rats with rhGH was found to boost the immune system, and team member Gregory Fany experimented on himself in 1990 and found rhGH appeared to rejuvenate his thymus and boost his immune system.
The thymus gland converts white blood cells to T cells and plays a role in immune response, with age fatty deposits develop in the thymus, and there is a reduction in human growth hormone which results in a weakened immune response.
In this study 9 white male participants were given recombinant human growth hormone to investigate what happens to the thymus and the immune system who were monitored over a year. Participants were also given two drugs (DHEA and metformin) to help ward off diabetes as rhGH has been found to contribute to the disease. After one year 7 of the participants were found to have lost fat in their thymus and healthy tissue had grown in its place. Epigenetic marker methylation testing was also conducted which showed that all of the participants had experienced reverse epigenetic aging; on average the participants had grown biologically younger by 2.5 years.
It was noted that the study was limited and that further study is required to replicate findings and to determine if human growth hormone can reverse the aging process.