Sublingual and oral forms show similar absorption in most research
My personal protocol to keep my periods regular is eating for blood sugar balance, eating a high-protein diet, taking thyroid meds on an empty stomach, reducing caffeine intake (no more than three cups of black tea per day), taking two capsules per day of MTHFR Pathways , taking 2000 mg of myo-inositol per day (which is actually closer to a PCOS dose of myo-inositol than the Hashimotos dose of 600 mg), and trying Beeya seed cycling
Oral supplementation (50150 g daily) may suit dietary deficiency without nerve involvement, but malabsorption cases require injections
Understanding when to talk to doctors about B12 dosage is important for safe treatment of neuropathy
Frequency varies by individual
This provides valuable insight, especially for the vegan or vegetarian athlete with a genetic tendency to inadequately process or absorb vitamin B12