In the case of B12, it could be recommended that you provide 100% if it is a daily supplement and you do not eat several fortified foods every day.
Its forms should be those that to date have been most studied for their bioavailability, such as: iron bisglycinate, cyanocobalamin, zinc bisglycinate, etc. In the case of B12, it could be recommended that you provide 100% if it is a daily supplement and you do not eat several fortified foods every day.