VITAMINS
Vitamin B12 (methylcobalamin)
Methylcobalamin, an active form of vitamin B12, supports energy, nerve function and red blood cell formation.
Also known as: B12, cobalamin, methylcobalamin, methyl B12, vitamin B-12
At a glance
- Form
- Methylcobalamin
- Category
- Vitamins
- In an apiece formula
- 1,000 mcg a day (you can change it)
- Recommended intake
- 2.4 mcg
- Upper limit
- No established UL
- Studied for
- Energy & vitality*
- Reference
- NIH ODS: Vitamin B12 fact sheet
Who should be careful
Our safety rules leave vitamin B12 out of a formula, or keep the amount lower, with:
Kept to a lower amount with
- Phosphate binder
- Dialysis
- Chronic kidney disease
- Advanced kidney disease
Always check with your doctor or pharmacist before adding a supplement if you take medication, are pregnant or nursing, or have a health condition. Stay under the upper limit from all sources combined, including multivitamins.
Symptoms it’s studied for
- Tired or low energy
- Brain fog or poor focus
- Anxious or stressed
- Bloating or gas
- Constipation or irregularity
- Hair shedding
- Muscle cramps or twitches
From the Journal
- Are personalized vitamins worth it? Personalized blend vs a multivitamin
What a standard multivitamin does well, where it falls short, what research says about personalized nutrition, and how to tell whether a personalized blend makes sense for you.
- Folic acid vs methylfolate: does your MTHFR gene matter?
How folic acid and L-methylfolate differ, what an MTHFR variant does and doesn't mean, what the pregnancy guidance actually says, and the upper limit for folic acid.
- Which supplements interact with common medications?
The best-documented supplement and medicine interactions, from vitamin K and warfarin to St. John's wort, minerals and thyroid medicine, and 5-HTP with SSRIs.
- Which blood tests should you check before taking supplements?
The blood tests that can usefully guide supplements, what each one can and can't tell you, and when to recheck after you change what you take.
- Why am I always tired, and what causes the afternoon crash?
The everyday reasons for constant tiredness and the 3 pm slump, which blood tests to ask your doctor about, which nutrients have been studied, and the signs that need a doctor soon.
- What is functional medicine, and how does it use supplements?
What functional and integrative medicine mean, how practitioners use history and labs to choose supplements, and how to judge the evidence and the marketing yourself.
Questions
How much vitamin B12 a day?
apiece formulas usually include 1,000 mcg a day. The recommended intake for adults is 2.4 mcg. Upper limit: No established UL.
What is vitamin B12 used for?
Methylcobalamin, an active form of vitamin B12, supports energy, nerve function and red blood cell formation. In apiece it is part of formulas for Energy & vitality.*
Who should be careful with vitamin B12?
apiece’s safety rules leave it out or limit it with: Phosphate binder; Dialysis; Chronic kidney disease; Advanced kidney disease. Check with your doctor or pharmacist if any apply to you.
Can I get vitamin B12 in a personalized supplement?
Yes. apiece builds one daily blend around your goals and, if you have them, your lab results. Vitamin B12 can be part of it at the amount listed, with every ingredient shown and never more than 10 capsules a day.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This page is general information, not medical advice. Check with your doctor or pharmacist before starting a supplement, especially if you take medication, are pregnant or nursing, or have a health condition. Updated 2026-10-21.