It sends B12 straight into the blood, skipping the guts absorption hurdles
nicotine and flavoring aerosols also drive oxidative stress
Given that there is no placebo-controlled human data, no established dose, and a mechanism whose foundational papers were retracted, an absence of noticeable effect is fully consistent with the current evidence it does not necessarily indicate a defective product, the wrong route, or an insufficient duration
Some companies and research consortia are now investing in phytopharmaceutical development essentially taking promising herbal compounds through the full drug development pipeline (purification, formulation, trials)
Like nasal sprays, capsules are non-invasive and appealing for regular use [10, 24, 26]