Retatrutide pen is a term used for an injection-device format associated with retatrutide, an investigational triple hormone receptor agonist targeting GLP-1, GIP, and glucagon receptors. It is being studied for its potential role in weight management and metabolic health. Retatrutide is not an approved routine prescription treatment, and products marketed online may not have verified quality or authenticity. Consult a qualified healthcare professional for reliable information about its investigational status and safety.