Honestly, Pablo, and I know you're looking for pill recommendations, your best bet for B vitamins would be to eat or juice more of these vegetables each day, and get natural sources of B vitamins:
Asparagus, Broccoli, Brussel Sprouts, Collard Greens, Green Peas, Mustard Greens, Spinach, or Turnip Greens.
I know the fresh variant is less convenient and usually more expensive, fresh is provably more beneficial than processed. Read a little bit about
Gerson Therapy and see why I think you should reconsider.