Medically reviewed by Sohaib Imtiaz, MD Key Takeaways Take vitamin B12 on an empty stomach in the morning or early afternoon to maximize absorption and avoid sleep disruptions.Vegans, older adults, and those with certain health conditions affecting nutrient absorption are at higher risk of deficiency.

Generally, taking your vitamin B12 consistently is most important, but there is a time of day you might want to prioritize taking it.