Growth hormone secretagogue peptides fall into two categories: 'type one' GHRH-mimicking peptides (sermorelin, tesamorelin, CJC-1295) which are mostly human-tested and in several cases FDA-approved, and 'type two' growth-hormone-releasing peptides (ipamorelin, hexarelin, GHRP-2/3/6, MK-677) which act by mimicking or stimulating ghrelin and thus also increase hunger and anxiety.