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A low level can also mean that you are over-methylating

Nat Commun 13 , 841 (2022)

The thread on tests for PA and B12 deficiency mentions other tests that can help to diagnose PA eg gastrin test and others (link in my other reply) Forum Support in reply to When you were tested for coeliac disease

Somethings different

Some patients notice increased energy or mental clarity within hours to days, while others experience gradual improvement over multiple sessions

Effect of intranasal administration of neuropeptide Y and single prolonged stress on food consumption and body weight in male rats
