Yeah you can do pushups with just your weiner with B12.
No really, you should really do some research.
But since its apparent you didn't here some info.
Vitamin B12 is needed for normal nerve cell activity, DNA replication, and production of the mood-affecting
substance SAMe (S-adenosyl-L-methionine). Vitamin B12 acts with folic acid and vitamin B6 to control homocysteine levels. An excess of homocysteine is associated with an increased risk of heart disease, stroke, and potentially other diseases such as osteoporosis and Alzheimer’s disease. Vitamin B12 deficiency causes fatigue.