Vitamin B 12 can also be absorbed by passive diffusion, but this process is very inefficient only about 1% to 2% of the oral vitamin B 12 dose is absorbed passively (2)
See where it ranks against the evidence-backed essentials in our guide to the top supplements for endurance athletes, or learn how to stack your nutrition for peak performance in our VO2 Max Supplements Guide
Severe allergic reactionssuch as difficulty breathing, rash, or swelling of the face and throatare extremely rare but require immediate medical attention
Vitamin B12 comes in many forms, however, sublingual B12 (taken under the tongue) is one option (NIH, 2020)
B12 injections can help to boost energy levels, reduce fatigue, and support muscle growth and recovery
Cognitive Difficulties : Memory loss, confusion, and trouble focusing