That's a meaningful body of circumstantial evidence, but it's not the same as clinical proof of efficacy in humans
Vitamin B-12 is essential for the creation of DNA and the metabolism of cells, and deficiencies in these can lead to anemia, fatigue, muscle weakness, digestive issues, nerve damage, and mood swings
Assessment of body composition in health and disease using bioelectrical impedance analysis (BIA) and dual energy X-ray absorptiometry (DXA): a critical overview
It simulates absorption, distribution, and elimination hour-by-hour to plot your estimated blood concentration curve, and calculates how close you are to steady state the point where the amount entering your body each week equals the amount being eliminated
10.3390/ijms252011040 184 ParkM