Doctors and nutritionists alike recommended dietary allowance (RDA) for vitamin B12 is 2.4 micrograms per day for adults aged 19 years or older
Practically: document diagnosis, insulin use (if applicable), and/or specific hypoglycemia events
However, as with many experimental compounds, its unregulated nature makes it high-risk for athletes
Additionally, many ME/CFS patients experience symptoms similar to bacterial or viral infections which may correlate to specific regions
4 from United States, 3 from Japan
140 A meta-analysis published in 2023 analyzing three observational studies identified that serum vitamin D levels were 22% lower in patients with tinnitus compared to those without, suggesting lower vitamin D levels may be a contributing factor to tinnitus