Posted by www.iwanttoquitsmoking.com OTC NRT versus OTC placebo studies The OTC NRT versus OTC placebo trials were all randomised, parallel groups studies in which subjects received free product. The first study by Schneider et al29 was the only placebo controlled OTC study of nicotine gum. The study was published in 1983, 14 years before the next study and had a much smaller sample size (n = 36) than other OTC studies. In addition "laboratory changes" resulted in a notably uneven distribution.