For those with normal absorption and adequate B12 stores, injections provide no unique metabolic advantage
Research shows clear benefits: Better stability than oral delivery, which exposes peptides to harsh stomach conditions Less breakdown by enzymes that would destroy the peptide before it reaches the blood Easier compliance no needles, no mixing, just spray Potential for targeted delivery to specific tissues, including the brain via the olfactory pathway Nasal delivery works very well for peptides like BPC-157 that target the whole body
Neither approach replaces the other
The FDA has not approved these peptides for obesity treatment (FDA guidance on unapproved peptides)
Some research also suggests that if you become vitamin B12 deficient, it can increase your risk of age-related macular degeneration (AMD), which is a gradual type of vision loss common in people over 50
If your B12 deficiency is due to an autoimmune disease or something that's not related to diet, you may need to get injections every two or three months for the rest of your life
