Peptides are chains of amino acids, while steroids are ring-shaped fatty molecules. Both can help you build muscle and burn body fat, but they do it through different processes. And while peptides don't seem to have many side effects, steroids can have many serious and sometimes permanent side effects
Steroids increase testosterone levels unnaturally in the body whereas peptides simply increase the signal allowing the body to create more of this hormone naturally. So, peptides are the much safer option