Modifiers matching peptide:

• active,
• natural,
• foreign,
• endogenous,
• addictive,
• anticancer,
• psychoactive,
• synthetic,
• analgesic,
• interesting,
• antigenic,
• minor,
• proinflammatory,

Simple categories matching psychoactive:

• property,
• substance,
• pharmaceutical,
• benzodiazepine,
• drug,
• agent,
• plant,
• herb,
• cactus,
• ligand,
• constituent,
• stimulant,
• alkaloid,
• effect,
• medication,
• peptide,
• intoxicant,
• food,
• compound,
• amine,
• chemical,
• medicine,