Importantly, nasal sprays enable rapid absorption through the nasal mucosa, allowing the peptide to bypass first-pass metabolism and enter systemic circulation with greater efficiency
Potential long-term health consequences
At ThinWorks, we recommend trying both to see what works best for you
When given by intramuscular injection, the dose bypasses the digestive tract and is absorbed reliably, which matters because dietary B12 absorption depends on stomach acid and a protein called intrinsic factor, both of which decline with age, medication and certain gut conditions
But this year after testing my thyroid was told to do exercise
A physician investigating unexplained hypercobalaminemia will typically order some combination of the following: Complete blood count (CBC) with differential to check for abnormal red blood cell, white blood cell, or platelet counts Liver function tests (ALT, AST, ALP, bilirubin, albumin) to assess liver health Kidney function tests (creatinine, BUN, estimated GFR) to evaluate renal clearance Peripheral blood smear if a myeloproliferative disorder is suspected Abdominal imaging (ultrasound or CT) if liver or abdominal pathology is a concern Cancer-specific markers or screenings if clinical suspicion warrants them The NIH Office of Dietary Supplements fact sheet notes that observational data from a Danish registry analysis of 757,185 people found the adjusted 1-year cancer risk was 1.74 to 4.72 times higher among those with B12 above 813 pg/mL compared to those in the normal range of 203 to 813 pg/mL