Robert F Kennedy Jr has left social media users scratching their heads after the Health and Human Services secretary nominee was recorded administering droplets of a mysterious blue liquid into his drink on board a flight.

Kennedy Jr. was spotted on a plane adding a blue liquid to his drink in a viral video that has sparked speculation online. Newsweek reached out to a representative for RFK Jr. outside of regular working hours via email for comment.

Robert F. Kennedy Jr. is going viral on social media after he was caught on camera adding a mysterious blue liquid to his in-flight beverage, and internet sleuths believe they know what it is. The leading theory among X users is that the prospective health secretary was dosing his drink with methylene blue.