the term B50 reminds me of the odd circumstance many years ago where an acquaintance took something marketed as B50. In it were high dose B vitamins, several of them occurring as 50 mg or 50 units or whatever it was, including B6 50 mg. B6 at 50 mg. is a high dose for B6, too high for many people. My acquaintance took this pill for two days, then ended up in the ER with seizures. She had not had a seizure before.
Later, I learned that many people cannot metabolize that much B6. I never order a multi-vitamin or B complex which has that high a dose of B6. My present multi-vitamin has 8 mg. of B6.
There is a way to get more B6, that is to take pre-metabolized B6, called sometimes p5p. Most people don't need to do this, but it is available if needed.