Processed foods are sometimes fortified with B12 to enhance their nutritional value
B12 testing involves measuring serum B12 levels, though methylmalonic acid and homocysteine tests provide more accurate assessments of functional B12 status
For this reason, patients with Parkinsons disease on levodopa therapy should avoid high B intake unless they are also taking carbidopa (which prevents this interaction)
(2) Varadraj Vasant Pai, Prasana Bhandari, and Pankaj Shukla (2017) Topical peptides as cosmeceuticals Indian Journal of Dermatology Venereology and Leprology, 2017 Jan-Feb, Volume 83 (Issue 1), Pages 9-18
My bottom line: a balanced view Thoughtful use, open communication and routine monitoring keep B12 injections useful and safe
Clinical Toxicology , 47 (2), 101111