glutathione top 10 ConsumerLab | Recent tests found that many supplements sold on Amazon failed label claims. Only 6 of 12 products contained their claimed Glutathione Lightening Serum: Top 10

But some bodies don't pull B12 from pills efficiently

Yes for most adults when supervised by a qualified provider

There are 2 primary mechanisms: Ascorbic Acid (Ascorbate) uptake using sodium-dependent vitamin C transporter (SVCT) 1 or 2 Ascorbic Acid (Ascorbate) Recycling Ascorbic Acid (Ascorbate) transport using sodium-dependent vitamin C transporter (SVCT) 1 or 2 As shown below, SVCT 1 and SVCT 2 transport ascorbic acid or ascorbate into the cell against the concentration gradient (represented by the orange wedge in the figure below)

5 IM Injections For Glutathione Intramuscular (IM) injections are administered directly into a muscle, typically in the upper arm or buttock area