Blinding effect of sham Fu's subcutaneous needling in a healthy population

Fu's subcutaneous needling (FSN) has been shown potential positive effectiveness in clinical practice. However, its specific effects are still not clear. This study aims to evaluate the blinding effect of a non-penetrating sham FSN needle, developed for the first time by the authors' research team in healthy participants. Furthermore, to provide a reliable control tool to assess the specific effects of FSN. We conducted a randomized, sham-controlled trial in 60 healthy participants divided into FSN group and sham FSN group in a 1:1 ratio. The participants were assessed according to blinding index (BI), pain intensity, sensation type and acceptability of needling. The James' BI was (0.56, 95 %CI [0.45, 0.67]) for two groups. The Bang's BI was (0.50, 95 % CI [0.24, 0.76]) in the FSN group and (−0.36, 95 % CI [−0.67, −0.07]) in the sham FSN group. There was no significant difference between needling pain intensity ( P > 0.05) and type of needling sensation. A total of 96.6 % participants who received sham FSN and 86.6 % participants who received FSN considered the needling acceptable or better. This study confirmed the effective blinding capability of the sham FSN needles in healthy participants, indicating that the novel non-penetrating sham FSN needle can be served as eligible control to evaluate the specific effects of FSN.