What happens when you take choline with vitamin b12?
This is a cooperative, low-risk pairing rather than a clash. Both nutrients feed the body's machinery for recycling homocysteine back into methionine, and they do so through two parallel routes that back each other up.
- The methionine synthase route fires first. The most familiar pathway uses 5-methylfolate as the methyl donor and methylcobalamin (vitamin B12) as a cofactor. When folate and B12 are plentiful, this enzyme carries most of the load.
- The BHMT route provides backup. Betaine-homocysteine methyltransferase (BHMT) uses betaine, the oxidation product of choline, as the methyl donor. It works mainly in the liver and kidneys and picks up more of the work when folate or B12 is marginal.
- The two pathways complement each other. When choline (and therefore betaine) is plentiful, the BHMT route can help compensate for low folate or B12 status. Dietary choline and betaine intake are associated with lower plasma homocysteine, an effect that appears strongest in people with low folate or B12.
Because the two nutrients support different arms of the same process, meeting both needs helps keep methylation running even when one pathway is stressed.
Why is this important?
Methylation is one of the body's most fundamental reactions. It produces S-adenosylmethionine (SAMe), the universal methyl donor used to make phospholipids such as phosphatidylcholine, to support neurotransmitter metabolism and creatine synthesis, and to regulate genes through DNA methylation.
When methylation is poorly supported, homocysteine tends to rise and SAMe tends to fall. Adequate choline matters in its own right too: phosphatidylcholine is needed to export fat from the liver, and controlled feeding studies show that frank choline deficiency can cause fatty liver and muscle changes.
The practical point is about adequacy, not danger. The link between choline intake and lower homocysteine is most pronounced in people with marginal folate or B12 status, which is exactly the group most likely to lean on the BHMT pathway. Older adults, vegans (whose richest choline foods, eggs, liver, and meat, overlap heavily with the richest B12 sources), and people taking metformin or acid-suppressing drugs are the most likely to fall short on both at once.
What should you do?
There is nothing risky to time or separate here, so the guidance is simply about meeting both needs reliably. Choline does not yet have an RDA, only an Adequate Intake, and most multivitamins supply little or no choline, so food matters.
Before changing anything: Take stock of your usual diet. If you regularly eat eggs, liver, fish, or soy, you are probably meeting much of your choline need already. If you eat little animal food, or you are pregnant, over 50, vegan, or taking metformin or a PPI, flag this with your doctor or pharmacist so they can check whether B12 and choline are both covered.
Every day: Aim to hit your choline Adequate Intake mostly from food, and pair it with a B-complex or multivitamin that supplies vitamin B12. Take supplements with a meal. If your diet is low in eggs, liver, and meat, a choline supplement (choline bitartrate, citicoline, alpha-GPC, or phosphatidylcholine) is a reasonable addition alongside B12.
After a change: Stay within the recommended ranges on the label rather than chasing high doses. Very high choline intake can cause a fishy body odor, sweating, low blood pressure, and stomach upset, so more is not better. If you start a supplement and notice any of these, ease back and discuss it with your pharmacist.
Which specific products are affected?
Dedicated choline supplements include Jarrow Citicoline, Now Foods Choline Bitartrate, Designs for Health PhosphatidylCholine, and Alpha Brain (which contains alpha-GPC). Several prenatal vitamins, such as Ritual Prenatal, Needed Prenatal, and FullWell, now include choline because the requirement rises in pregnancy and most prenatal formulas historically underdelivered it.
Standard B-complex and multivitamin products usually supply B12 but not meaningful choline. Liver-support and methylation-support formulas (for example Designs for Health Homocysteine Supreme and Thorne MediClear) often combine choline, betaine (TMG), B12, and folate in one product. The richest food sources of choline are eggs, beef liver, fish, and soy.
The science behind it
The biochemistry here is well established. The Linus Pauling Institute Micronutrient Information Center summarizes how choline-derived betaine and the folate/B12 pathway provide two parallel routes for remethylating homocysteine, and why choline can partly compensate when folate or B12 status is low.
Human observational data support a real but modest dietary association. Chiuve and colleagues found that higher betaine and choline intakes were associated with lower plasma homocysteine in women, with the relationship more apparent in those with lower folate status. This is correlational nutritional evidence, not proof that supplementing choline lowers disease risk, so the claim is best framed as supportive physiology rather than a strong clinical effect.
Frequently Asked Questions
Is taking choline and B12 together dangerous?
No. This is a cooperative nutritional pairing, not a harmful interaction. Both nutrients support the same methylation process through complementary pathways.
Do I need to take them at different times of day?
No. There is no timing conflict between choline and B12. Taking them together with a meal is fine.
If I take enough B12, do I still need choline?
Yes, choline has roles beyond homocysteine recycling, including liver fat export and phospholipid synthesis. B12 does not replace those functions, so both nutrients matter.
Who is most likely to fall short on both?
Vegans, older adults, and people taking metformin or acid-suppressing drugs are most at risk, partly because the richest choline foods overlap with the richest B12 foods.
Can I get enough choline from food alone?
Often yes, if your diet includes eggs, liver, fish, or soy. People who eat little animal food may find a supplement easier, but it is not mandatory if intake is adequate.
Can you take too much choline?
Yes. Very high intakes can cause a fishy body odor, sweating, low blood pressure, and stomach upset. Stay within label-recommended ranges and review high-dose use with your doctor or pharmacist.
Key takeaways
- Choline (via betaine) and vitamin B12 feed two parallel homocysteine-remethylation pathways, so meeting both needs supports healthy methylation.
- This is a benign nutritional synergy, not a risky drug interaction, and there is no need to separate them in time.
- The benefit of choline for homocysteine is most apparent in people with marginal folate or B12 status, based on observational human data.
- Get choline mostly from food (eggs, liver, fish, soy) and pair it with B12 from a B-complex or multivitamin.
- Vegans, older adults, and people on metformin or acid-suppressing drugs are most at risk of falling short on both, and should review intake with their doctor or pharmacist.