Indeed, the effects of C12TPP on food intake resemble the effects of the anorexic gut peptide YY.54 Development of tolerance to appetite suppression appears to be a common feature of many anti-obesity drugs: for example, rimonabant, sibutramine and tesofensine (reviewed in Fernstrom et al.55). Here, PYY is linked to obesity due to melanocortin 4 receptor deficiency.