Clinically, however, the evidence is mixed : Vitamin B12 has a well-established role in energy metabolism, especially in deficient individuals
Men should avoid applying it right after shaving if the skin feels irritated
When evaluating side effects, the following frequencies are used as a basis: Very common: more than 1 in 10 people Common: less than 1 in 10, but more than 1 in 100 patients Uncommon: less than 1 in 100, but more than 1 in 1000 patients Rare: less than 1 in 1,000 but more than 1 in 10,000 patients Very rare: less than 1 in 10,000 patients treated, or unknown
H2 Receptor Antagonists: Ranitidine and Other Acid Reducers H2 receptor antagonists, like ranitidine, can lower vitamin B12 absorption