Low B12 levels may lead to tiredness, weakness, cognitive difficulty, or numbness and tingling in the extremities
Angew Chem Int Ed Engl 58(23):77977801
In contrast the findings for glutamine were inconsistent with two studies reporting no significant difference in serum glutamine in children with autistic disorder compared with controls [69, 89], a later study reporting a significant decrease in platelet glutamine in children with autistic disorder [68] and further studies that reported serum glutamate to be significantly higher in adults with autistic disorder [75] and children with autism spectrum disorders (mixed diagnoses) than controls [87]
From this information, they developed a remediation plan to resolve the issues that resulted from the adverse reaction to the injection
The clear answer is yes when taken in the right form, dosage, and routine, glutathione and collagen are safe to take together and are often more effective when combined
"Glutathione metabolism and its selective modification"