Abstract: The present invention relates to a (poly)peptide or a peptidomimetic thereof having the biological activity of Conkunitzin-S1, wherein said (poly)peptide is selected from (a) a polypeptide comprising or having the amino acid sequence of SEQ ID NO: 1; (b) a polypeptide having at least 85% sequence identity to SEQ ID NO:1; or (c) a fragment of a) or b); wherein said (poly)peptide or peptidomimetic specifically modulates the activity of a channel having the activity of a Kv1.7 containing channel, for the treatment or prevention of metabolic diseases or conditions, or secondary diseases or conditions related to said metabolic diseases or conditions. The present invention furthermore relates to a method of screening for (poly)peptides derived from Conkunitzin-S1 suitable for specifically modulating the activity of a channel having the activity of a Kv1.