The safe dosage of Vitamin B12 varies depending on the individual's age and dietary needs. For adults, the Recommended Dietary Allowance (RDA) is 2.4 micrograms per day¹². In pregnancy, this increases to 2.6 micrograms, and for breastfeeding women, it's 2.8 micrograms¹.

Vitamin B12 is considered safe because it is water-soluble, meaning excess amounts are excreted through urine, and no adverse effects have been associated with its high intake from food and supplements in healthy individuals³. Even high doses, such as 1000 micrograms per day, used to treat deficiencies, are considered safe⁴.

There is no established Tolerable Upper Intake Level (UL) for Vitamin B12 as it has not been shown to cause harm². However, some evidence suggests that very high doses (25 micrograms per day or higher) might increase the risk of bone fractures⁵. Thus, it's generally safe, but it's always advisable to consult with a healthcare provider before beginning any high-dose supplementation.

Footnotes

1. Office of Dietary Supplements - Vitamin B12 ↩ ↩²

2. Vitamin B12 - Dietary Reference Intakes ↩ ↩²

3. Vitamin B12 ↩

4. Vitamin B12 - Mayo Clinic ↩

5. Vitamin B12 - Harvard ↩