'peptide-containing' originates from modern English as a compound of 'peptide' and the present-participle form 'containing' of the verb 'contain'. 'peptide' ultimately comes from Greek via German: German 'Peptid' (scientific coinage) from Greek root 'pept-'/'peptein' meaning 'to digest', and 'containing' derives from Latin 'continēre' (con- + tenēre) meaning 'to hold together or within'.

'peptide' passed from Greek roots ('peptein', 'peptos') into scientific Neo-Latin/German ('Peptid') in the 19th–20th century and was adopted into English as 'peptide'; 'contain' evolved from Latin 'continēre' → Old French 'contenir' → Middle English forms (e.g. 'containen') → modern English 'contain', with 'containing' as the present participle.

Initially the Greek root related to 'digestion' or 'cooked' substances; over time 'peptide' became the technical term for a short chain of amino acids. 'Contain' originally meant 'to hold together/within' and has retained the sense of 'having something inside'; combined, 'peptide-containing' now specifically means 'having peptides present (as an ingredient or component)'.