Daily How Much

Most adults with diabetes aim for 2.4 mcg of vitamin B12 daily, with 25–100 mcg supplements used if diet or medicines lower levels.

Most healthy adult women need about 2.4 micrograms of vitamin B12 per day, with slightly higher amounts during pregnancy and breastfeeding.

Most adults on metformin often take 500–1000 micrograms of vitamin B12 daily, set after blood tests and a shared plan with their doctor.

Most healthy adult men only need about 2.4 micrograms of vitamin B12 a day, usually met through a mixed diet or a modest supplement.

Most healthy adults need about 0.0024 mg (2.4 mcg) of vitamin B12 per day, with slightly higher amounts during pregnancy and breastfeeding.

Healthy adults need about 2.4–2.8 mcg of vitamin B12 per day, and up to 2 mg daily from supplements appears safe for long-term use.

One standard 8.4 oz Red Bull contains around 5 micrograms of vitamin B12, with larger cans delivering even more per serving.

One large chicken egg contains around 0.6 micrograms of vitamin B12, roughly one quarter of the daily amount recommended for healthy adults.

One cup of cow’s milk usually provides around 1.1 micrograms of vitamin B12, which covers close to half of an adult’s daily need.

Most healthy adults need about 2.4 micrograms of vitamin B12 per day, with a small increase during pregnancy and breastfeeding.