Sporadic, haphazard application will lead to disappointing results
Vitamin B12 boosts energy levels and metabolism, but it will never work unless you do something about it, which is still proper diet and exercise
The staff are very friendly and not much of a wait time
Methionine metabolism in health and cancer: a nexus of diet and precision medicine
These symptoms may suggest inadequate B12 replacement, concurrent iron or folate deficiency, or alternative haematological conditions requiring investigation
Look for third-party testing (certificate of analysis), domestic US shipping (faster, fewer customs issues), and a verifiable track record