These links below are a start for looking at research studies on tapping (EFT). There continues to be research done on it.
Veterans Project
http://stressproject.org/scientific-research/research-information/
Mercola.com article
http://articles.mercola.com/sites/articles/archive/2013/12/26/emotional-freedom-technique.aspx
EFT Universe Tapping Research
http://www.eftuniverse.com/research-studies/eft-research#top
http://www.eftuniverse.com/eft-related-press-releases/study-finds-eft-tapping-lowers-cortisol-significantly
Research Review PDF
http://innersource.net/ep/images/stories/downloads/Acupoint_Stimulation_Research_Review.pdf
NCBI Group Borrowed Benefits
www.ncbi.nlm.nih.gov/pubmed/29468884
VA Approves EFT for treating VETs, it was studied in over 100 clinical trials
https://www.huffpost.com/entry/veterans-administration-approves-eft-emotional-freedom_b_597fc82ee4b0cb4fc1c73be2?ncid=engmodushpmg00000003

Development of Tapping
EFT means "Emotional Freedom Technique". We mostly use the term "Tapping”. EFT was developed by Gary Craig in the 1990's. Since then tapping has been refined by many practitioners and used around the world. Tapping is so natural that many people do it without thinking, such as tapping a foot to deal with stress.
EFT means "Emotional Freedom Technique". We mostly use the term "Tapping”. EFT was developed by Gary Craig in the 1990's. Since then tapping has been refined by many practitioners and used around the world. Tapping is so natural that many people do it without thinking, such as tapping a foot to deal with stress.