Brain Fog or B12? The Hidden Nutrient Deficiency Mimicking Memory Loss

5. Recommended Dosages and Correct Usage
The daily intake for a typical adult is about 2.4 micrograms, but if a deficiency is diagnosed, therapeutic doses are much higher (between 500 to 1000 micrograms). Sublingual (under-the-tongue) supplements or oral sprays are much more effective than swallowable pills for people with low stomach acid, as they enter the bloodstream directly through the oral mucosa.