This requires drawing blood or collecting a urine sample
The vitamin can be stored in the liver for a long time, so it may take a few years for a deficiency to develop ( Summary Vitamin B12 is a water-soluble vitamin that plays an important role in brain function and red blood cell production
doi:10.21037/tau.2018.08.14
Based on this publication, the conversion rate from rat to human doses is about 1:6.2
Social media, podcasts, and influencer culture have really accelerated the awareness, says Jen Sogol Ash, ND, a doctor of naturopathic medicine, functional medicine expert, and a longevity director at Concierge MD and Drip Hydration in Los Angeles
Cycle length 8 to 12 weeks on, 4 to 6 weeks off in common research community protocols