A minimum of 90 healthy subjects ranging from 20 to 25 years will be selected from students in Accademia Itliana di Medicina Osteopatica, Saronno, Italy (AIMO) and randomly assigned to the placebo, control or the CV4 arm. Randomization will account for sex and score in the STAI- 2 (form Y) questionnaire, assessing trait anxiety for each subject.