I've found mixed information online about using Spirulina as a source of vitamin B12 for humans when searching google for "Spiralina B12".
For instance the first match states that Spirulina has a mix of B12 analogues which are often inactive.
And the second match states: "Spirulina is a rich source of B12. Despite that, some experts believe that in B12 in spirulina is in a form that is not absorbed.
However, a 2010 study in the Journal of Agricultural and Food Chemistry found the opposite. It showed that B12 in spirulina contains 'methylcobalamin, a form of B12 of high biological activity'."
but doesn't name the study, so I can't find which study it is referring to in 2010.
Can Spirulina be used as an effective source of B12 for humans? If so how, and according to what research.