It’s been found to deliver “no significant effect” [1], produce “no significant difference” [2], and have “no effect” [3]. Please stop wasting your breath.
1: https://www.ncbi.nlm.nih.gov/pubmed/11761499 (2001)
2: https://www.ncbi.nlm.nih.gov/pubmed/16023511 (2005)
3: https://www.ncbi.nlm.nih.gov/pubmed/16569567 (2006)