doi: 10.1002/hep.29367 4
That's why nothing has worked yet
The use of parenteral injections can sometimes give rise to toxic reactions as well as allergic type responses with respiratory distress
Purification to homogeneity and characterization of human B-cell differentiation factor (BCDF or BSFp-2)

Beef liver, cooked, pan-fried (3 ounces) Amount in micrograms (mcg): 70.7 mcg Clams (without shells), cooked (3 ounces) Amount in micrograms (mcg): 17 mcg Oysters, eastern, wild, cooked (3 ounces) Amount in micrograms (mcg): 14.9 mcg Nutritional yeast, fortified Amount in micrograms (mcg): 8.324 mcg Salmon, Atlantic, cooked (3 ounces) Amount in micrograms (mcg): 2.6 mcg Tuna, light, canned in water (3 ounces) Amount in micrograms (mcg): 2.5 mcg Beef, ground, 85% lean meat (3 ounces) Amount in micrograms (mcg): 2.4 mcg 2% milk, 1 cup Amount in micrograms (mcg): 1.3 mcg Yogurt, plain, fat free (6 ounces) Amount in micrograms (mcg): 1 mcg Breakfast cereal fortified with 25% of daily value Amount in micrograms (mcg): 0.6 mcg Cheddar cheese (1.5 ounces) Amount in micrograms (mcg): 0.5 mcg 1 large egg, whole, cooked Amount in micrograms (mcg): 0.5 mcg Turkey, breast meat, roasted (3 ounces) Amount in micrograms (mcg): 0.3 mcg Vitamin B12 Overdose: Key Takeaways Vitamin B12 is a crucial nutrient that supports a variety of important bodily functions, including red blood cell formation, neurological health, and DNA synthesis

For best results, use consistently for at least 3 months