Here's an explanation of those hormone types: Steroid hormones are lipid-soluble hormones derived from cholesterol. Because they are fat-soluble, they can easily pass through the cell membrane to bind to receptors inside the cell, influencing gene expression. Examples include estrogen, testosterone, and cortisol*. Peptide hormones are composed of chains of amino acids, ranging from a few to hundreds. They are water-soluble and cannot pass through the cell membrane, so they bind to receptors on the cell surface, triggering a signaling cascade inside the cell. Examples include insulin, growth hormone, and oxytocin*. Amino acid-derived hormones are synthesized from the modification of a single amino acid. Their solubility and mechanism of action can vary. For instance, adrenaline (epinephrine) and noradrenaline (norepinephrine) are derived from tyrosine and are water-soluble, while thyroid hormones* (T3 and T4), also derived from tyrosine, are lipid-soluble.