Robert F. Kennedy Jr. was recently seen adding a striking blue liquid to his drink while on an airplane. The footage, which quickly spread online, left viewers puzzled about the nature of the substance. The 72-year-old was caught on video dropping the vibrant cobalt-blue liquid into what appeared to be a cup of water. Some say it could be methylene blue.
While some social media users joked about the contents, medical experts believe and have tweeted that the substance is methylene blue, a synthetic dye with potential medical benefits.
That’s methylene blue that RFK Jr. is putting into his drink if I’ve ever seen it.
— Jesse Morse, M.D. (@DrJesseMorse) February 6, 2025
I did a post on yesterday if you’re interested. https://t.co/of7a1mHiYt
Though traditionally used for treating malaria, recent research suggests methylene blue may support cognitive function, slow aging, and combat certain diseases. However, much of this research has been conducted on animals or human cells, not on actual patients.
Originally developed in the late 19th century as a fabric dye, methylene blue was later repurposed to treat malaria. Today, it is FDA-approved for methemoglobinemia, a rare blood disorder that affects fewer than 100 Americans annually. Some studies suggest it may also help restore hemoglobin levels by converting iron in red blood cells.
Dr. Jesse Morse, a sports medicine physician, weighed in on social media, stating, “That’s methylene blue if I’ve ever seen it.” A source close to Kennedy also suggested he was using it as part of the biohacking trend. Whether for health benefits or another reason, Kennedy’s use of the substance has sparked widespread discussion.