
Methylene Blue is a synthetic compound used as a dye and a medication. In supplement form, it is sometimes used for its potential cognitive-enhancing and antioxidant properties, though the speaker warns about its side effects.
There's methyline blue where people take it and they think it's going to make them live forever. Don't take this. It literally will stain your nails blue and your hair blue.
"
"The speaker explicitly names Methylene Blue, noting that people take it for longevity but warning that it stains hair and nails blue."