Feeling worse after B12 Injection: Answering concerns. La Vie Med Spa McCartan's Boost Your Energy with ! Symptoms of low B12 includes: Constant fatigue Lack of energy Memory problems Pins and needles sensations Depression or mood Quick question why do people talk about B12 injections versus ingestible pills? I wish I injections. I do not have the cash for that little backstory. I've been eating vegan style for Vitamin B12 Injections: Boost Energy & Support Weight Loss It might not be your lifestyle it could be a B12 deficiency. B12 is essential for energy, mood, and overall wellness and when levels are low, your body feels it. Our Low B12 levels can lead to fatigue, numbness, irritability, and moreyet many people don't realize they're deficient. The good news? Testing and treatment are simple with options like injections or dissolvable tablets.