idk if this is still relevant but from the image on here: https://en.wikipedia.org/wiki/Methylcobalamin
i found this: https://www.sigmaaldrich.com/US/en/product/sigma/m9756
and they even show you a price on there
i found this: https://www.sigmaaldrich.com/US/en/product/sigma/m9756
and they even show you a price on there