Vitamin B12 is essential for energy production, nervous system function, and red blood cell formation. However, oral B12 supplementation doesn't work well for everyoneabsorption can be limited by digestive issues, certain medications, Sublingual B12 vs Injection WhyNotNatural How Quickly Does a B12 Shot Work? What to Expect Do B12 shots actually work? Short answer YESfor the right people. Benefits may include: Increased energy Better focus Improved metabolism Especially helpful if you're deficient. If