b12 injection vs oral supplement Lipotropic Injections vs. Supplements: Which Is More Effective for Weight Loss? B12 Shots vs. Oral Supplements:

That absorption gap is the whole point

www.cdc.gov

Research suggests that intramuscular delivery achieves significantly higher plasma concentrations than oral supplementation, making injectable Vitamin C a clinically effective option for patients with deficiency, compromised immune function, or chronic fatigue

How often to test: if your ferritin is in the optimal range, an annual check is usually enough

doi:10.1016/s0022-3476(88)80114-8

Finally, many of the common prescription medications (including the aforementioned acid blockers, as well as antibiotics, synthetic estrogens, and even birth control pills ) we see as problematic for the thyroid, can also cause inflammation in the gut, further affecting our ability to extract nutrients from food, and result in nutrient deficiencies