Dr Mesen is the founder, and the Chief Medical Officer of the Stem Cells Transplant Institute in San Jose, Costa Rica which is specialized in the treatment of human diseases using mesenchymal stem cells. Dr Mesen is also a co-founder and the Chief Medical Officer of the Anti-Aging and Wellness Clinic. Under his direction, the Anti-Aging and Wellness Clinic has grown to four clinics in three countries; two clinics in Costa Rica, one clinic in Tijuana, Mexico and one clinic in Panama City, Panama. He had also served as a Chief Medical Officer at Costagenics Age Management Program from 2007-2010 and after that, he worked for the Anti-Aging Institute of the Americas as a chief medical officer until 2013.

Dr Mesen has been an active member of the American Academy of Anti-Aging and Regenerative Medicine (AAARM) and the American College of Physicians Central America since 2009. In 2015, he became a member of the International Organization for Training and Medical Research (IOCIM). This organization is committed to ensuring quality healthcare in the countries in Latin America. In 2015, this organization awarded him the “Prize to the Medical by Achievement for a Better Life” award as a token of recognition towards his excellent academic career and continuous education and commitment to improving human life. In addition to this Dr. Leslie Mesen also received the award for Excellence in Healthcare from the IOCIM recognizing his leadership, outstanding performance and quality of service.

Dr Mesen has a passion for helping patients and has built both, the Stem Cells Transplant Institute and the Anti-Aging and Wellness Clinic on a foundation of research, scientific innovation, and individualized patient care. His focus is to improve the quality of life of each patient, while gaining a better understanding of cellular senescence and regeneration.