26/12/2025
Your B12 Tablet May Be 1000 µg… But Your Gut May Use Only 10 µg!”
You may be proudly taking a “strong” B12 tablet – 500 or 1000 micrograms – but your healthy gut can actively absorb only about 1.5–2.5 µg per meal, and the rest depends on only around 1% passive absorption.
That means from a 1000 µg tablet, your body may use only about 10 µg in many cases.
Around 1 in 5 people above 60 years (≈20%) may have B12 deficiency, often without knowing it.
B12 blood level below 150 pg/mL usually means clear deficiency and risk of anemia and nerve damage.
B12 mainly has 3 types:
Cyanocobalamin – synthetic, cheap, needs conversion.
Methylcobalamin – active, nerve-friendly form.
Adenosylcobalamin – active, works in energy pathways.
Risk is higher if:
You are >50 years,
Vegan / strict vegetarian,
Have gastritis, IBD, celiac, bariatric or ileal surgery,
Take metformin, PPIs, H2 blockers, OCPs for months to years.
A network meta‑analysis of 13 studies with 4,275 people showed tablets, sublingual drops and injections can all correct B12 deficiency well, but methylcobalamin showed better improvement in nerve symptoms in several trials.
B12 is not a general “energy tonic” for everyone.
It is a life‑saving vitamin for your nerves, blood and pregnancy, when deficiency is real.
If you are vegan, >50, or have gut/medicine risks – check your B12 once, do not guess.
After testing, your doctor may choose the right dose and right form (often methylcobalamin or hydroxocobalamin for nerve issues) instead of random 1500–5000 µg tablets or injections.
“Don’t count only the milligrams on the strip – count how much B12 your body can absorb, activate and use.
