There are more than 100 published clinical trials from the US National Institute of Health National Library of Medicine showing the benefits of Reiki, including:

• Kurebayashi LFS, Gnatta JR, Kuba G, Giaponesi ALL, Souza TPB, Turrini RNT. Massage and Reiki to reduce stress and improve quality of life: a randomized clinical trial. Rev Esc Enferm USP. 2020 Oct 12;54:e03612. Portuguese, English. doi: 10.1590/S1980-220X2018059103612. PMID: 33053005.
• Vergo MT, Pinkson BM, Broglio K, Li Z, Tosteson TD. Immediate Symptom Relief After a First Session of Massage Therapy or Reiki in Hospitalized Patients: A 5-Year Clinical Experience from a Rural Academic Medical Center. J Altern Complement Med. 2018 Aug;24(8):801-808. doi: 10.1089/acm.2017.0409. Epub 2018 Apr 5. PMID: 29620922; PMCID: PMC6422004.
• McManus DE. Reiki Is Better Than Placebo and Has Broad Potential as a Complementary Health Therapy. J Evid Based Complementary Altern Med. 2017 Oct;22(4):1051-1057. doi: 10.1177/2156587217728644. Epub 2017 Sep 5. PMID: 28874060; PMCID: PMC5871310.
• Winnegge, Kimberly Ann, "When East meets West : an exploratory study of how Reiki is integrated into psychodynamic practice" (2011). Masters Thesis, Smith College, Northampton, MA.