At the time, the FDA presented a lot of adverse event data that showed there was a risk of immunogenicity immune reactions and that raised some red flags for the committee, said Gupta, an adjunct assistant professor of anesthesiology at the Johns Hopkins University School of Medicine
When should I contact my healthcare provider about side effects
A 2025 meta-analysis of 16 studies involving 6,098 participants found no statistically significant difference between intramuscular, oral, and sublingual B12 supplementation routes
Its benefit depends heavily on exercise and baseline carnitine status: it is most useful for physically active people, vegetarians, and those with lower dietary intake, and shows little benefit as a standalone, sedentary-use supplement
This property makes it valuable for joint health