Does a med spa in Missouri need a medical director?

Short answer
The cited rules do not settle this — none require a med spa to name a medical director. They only limit Class E estheticians to surface cosmetic work and require medical practice to be by a licensed physician or delegated under a collaborative arrangement.

Missouri fixes the supervision burden in numbers, and it counts charts. a physician may enter collaborative practice arrangements with registered professional nurses, in the form of written agreements, jointly agreed-upon protocols or standing orders, and those arrangements may delegate authority to administer or dispense drugs and provide treatment — but only within the nurse’s scope of practice and consistent with that nurse’s skill, training and competence. The statute then fixes the review burden in numbers: the APRN must submit at least ten percent of the charts documenting their delivery of health care services for physician review every fourteen days, and the collaborating physician must review every fourteen days at least twenty percent of the charts in which the APRN prescribes controlled substances. Where the arrangement covers diagnosis and initiation of treatment for acutely or chronically ill or injured persons, the collaborating physician must be present for sufficient periods of time at least once every two weeks. Geographic proximity is required, subject to the exceptions the section itself sets out. Separately, delegating professional responsibilities to a person not qualified by training, skill, competency, age, experience or licensure is a ground for discipline. On the cosmetology side the licensed practice is enumerated: the Class E esthetician occupation is defined by a list of manual and apparatus-based skin practices, with cosmetic preparations not to exceed ten percent phenol.