Vitamin B12
Methylcobalamin
Last reviewed: June 2026 · Medically reviewed by a licensed pharmacist
What it does
B12 keeps your nerves insulated and firing properly and is needed to build healthy red blood cells that carry oxygen, which is why low levels often show up as fatigue and brain fog. It's found almost entirely in animal foods, so plant-based eaters and many people over 50 (who absorb it less well) commonly run low. We use the active methylcobalamin form.
The science
Vitamin B12 maintains nerve integrity, enables red blood cell formation, and supports DNA synthesis. Vegans and older adults are at highest deficiency risk.
Most relevant for
Vegans and vegetarians, adults over 50, and unexplained fatigue.
Key references
General wellness information, not medical advice. Consult your healthcare provider before starting any supplement. Build your personalized stack →