1. Peptide Hormones Peptide hormones or protein hormones are hormones whose molecules are peptides or proteins, respectively. Peptide hormones are hormones that consist of amino acids. Peptide hormones can be among the intracellular signalling peptides and proteins, and can include insect hormones, gastrointestinal hormones and thyroid hormones, but their actions are not limited to individual cells and they can act systemically. https://www.elementsarms.com/