Does Vitamin B12 Lower Cholesterol?

Vitamin B12 does not lower cholesterol the way a statin or other lipid-lowering drug does. No clinical trial has shown that taking a B12 supplement reduces LDL or total cholesterol in people who already have adequate B12 levels. The relationship runs in a different and more interesting direction: being deficient in B12 can push cholesterol upward through specific changes in how your cells regulate fat production. That distinction matters, because it means B12’s connection to cholesterol is real but conditional, and popping a supplement when you are not deficient is unlikely to move your numbers.

What Large Observational Studies Show

The strongest association data comes from a study of more than 20,000 adults that used advanced lipoprotein profiling to look at the relationship between B12 blood levels and various cholesterol markers. People in the highest quarter of B12 levels had meaningfully better lipid profiles: higher HDL cholesterol, lower triglycerides, lower levels of small dense LDL particles (the type most linked to artery damage), and a more favorable atherogenic index overall.¹ That pattern held after adjusting for age, sex, and other confounders.

Taken at face value, that sounds like B12 protects your lipid profile. But observational data can only show that two things travel together, not that one causes the other. People with higher B12 levels may eat differently, exercise more, or simply be healthier in ways the study could not fully account for. The question is whether giving B12 to someone with low levels actually changes their cholesterol, and that requires controlled trials.

What Happens When People Actually Take B12

The trial evidence is sobering for anyone hoping B12 is a cholesterol shortcut. A randomized controlled trial in patients with non-alcoholic fatty liver disease gave one group B12 supplements and another a placebo, then tracked their lipid panels. B12 supplementation did not change fasting triglycerides or LDL cholesterol, and while HDL drifted downward slightly in both groups, there was no meaningful difference between the supplement and placebo arms.²

A separate trial gave coronary patients a combination of folic acid, B12, and antioxidant vitamins. Homocysteine dropped sharply and LDL oxidation fell, but serum lipid levels themselves did not change at all.³ The oxidation finding is worth noting, since oxidized LDL is particularly harmful to arteries, but it is a different outcome from lowering cholesterol concentrations in your blood. In other words, B12 may make existing LDL particles slightly less dangerous without reducing their number.

A two-year trial in elderly people with high homocysteine tested whether B12 and folic acid improved markers of blood vessel health and inflammation. They did not. Measures of endothelial function and systemic inflammation changed at nearly identical rates in the supplement group and the placebo group.⁴ So even on related cardiovascular markers, supplementation in people who are not severely deficient does not seem to help.

How B12 Deficiency Raises Cholesterol at the Cellular Level

The gap between the observational associations and the trial results makes more sense once you understand the mechanism. B12 is not a lipid-lowering agent. It is a cofactor your cells need to regulate certain genes involved in cholesterol production. When B12 is scarce, one of the chemical reactions it supports, the conversion of homocysteine to methionine, slows down. That bottleneck reduces the supply of a molecule called S-adenosylmethionine, which your cells use to tag genes with methyl groups and keep them quiet.

Research on human fat cells and clinical samples from women at different reproductive stages found that when B12 is low, two genes that control cholesterol production, SREBF1 and LDLR, lose some of their methyl tags and become overactive. The result is that cells ramp up cholesterol synthesis on their own. In the clinical arm of the same research, women with lower B12 had higher total cholesterol, higher LDL, and a worse cholesterol-to-HDL ratio.⁵ A broader review of pre-clinical and clinical work confirmed that these epigenetic changes, along with effects on microRNAs and histone modifications, are plausible pathways through which low B12 disrupts lipid metabolism.⁶

This mechanism explains why the observational data looks strong but the supplement trials do not: if your B12 levels are already adequate, those genes are already properly regulated, and adding more B12 does nothing further. It is like filling a gas tank that is already full. But if you are genuinely deficient, correcting the deficiency could, in theory, restore normal cholesterol regulation. That specific scenario, correcting a true deficiency, has not been cleanly tested in a large randomized trial focused on cholesterol as the primary endpoint.

Who Is Actually at Risk for B12 Deficiency

The groups most likely to be deficient are the ones where the cholesterol connection becomes practically relevant. B12 comes almost exclusively from animal products, so vegans and strict vegetarians are at the top of the list. Estimates put the prevalence of subnormal B12 status at roughly half to three-quarters of vegetarians and vegans across studies in multiple countries.⁷ B12 levels below 300 pmol/L are associated with a significant risk of metabolic deficiency, and many vegetarians fall in that range.

Here is where the picture gets complicated. Vegetarians and vegans tend to have better cardiovascular risk profiles overall, including lower blood pressure, lower glucose, lower body weight, and improved serum lipids, compared to meat-eaters.⁸ Their diet protects them through several pathways even as it exposes them to B12 deficiency. Whether the rising homocysteine and subtle lipid shifts caused by that deficiency partially offset the cardiovascular benefits of a plant-based diet is an open question that researchers have flagged but not yet answered definitively. For vegans, supplementing B12 is already standard advice for neurological and blood-health reasons; the potential lipid benefit is a bonus argument for not skipping it.

The Metformin and Type 2 Diabetes Angle

Metformin, one of the most widely prescribed diabetes drugs in the world, is well known to deplete B12 over time. That creates a natural experiment: a large population of people who become B12-deficient not by choice but as a side effect of a medication they need. Studies in this group consistently show that B12 deficiency tracks with worse lipid numbers.

In a study of type 2 diabetic patients on metformin in Iran, those who were B12-deficient had significantly higher total cholesterol than those with normal B12 levels. The association remained statistically significant after adjusting for other variables, with deficiency linked to meaningfully elevated cholesterol.⁹ A larger study comparing European and Indian populations with type 2 diabetes found similar patterns: B12 deficiency was independently associated with higher triglycerides in both groups and a worse cholesterol-to-HDL ratio in the Indian cohort. Deficiency prevalence was around a quarter of European patients and about one in eight Indian patients, with rates climbing in those taking metformin.¹⁰

If you are on metformin, this is one of the more actionable pieces of the puzzle. Checking your B12 levels periodically and supplementing if needed may help keep your lipid profile from quietly worsening alongside your blood sugar management. Many endocrinologists already recommend this, but the lipid angle is not always part of the conversation.

Obesity, Insulin Resistance, and B12

People with obesity tend to have lower B12 levels, and that gap correlates with markers of metabolic dysfunction. A study comparing obese and non-obese individuals found that B12 was significantly lower in the obese group, while their triglyceride-to-HDL ratio and a triglyceride-glucose index (both markers of insulin resistance) were significantly higher. B12 levels were inversely correlated with both of those markers, and moderately correlated with insulin resistance measured by HOMA-IR.¹¹

Again, this is correlation rather than proven causation. Lower B12 in obesity could result from dietary patterns, reduced absorption, dilution in a larger body mass, or chronic inflammation. But the consistent finding across multiple populations, obese adults, diabetics on metformin, vegetarians, women of childbearing age, is that low B12 and unfavorable lipid markers travel together. The mechanistic work on gene methylation offers a plausible explanation for why that is not a coincidence.

Does B12 Interfere with Statins or Other Cholesterol Drugs?

If you are already on a statin and wondering whether adding B12 could help or hurt, the trial data is reassuring. A pilot study for the large SEARCH trial tested whether combining folic acid and B12 with simvastatin caused any interaction. The combination group saw an LDL reduction of about 55%, while the simvastatin-only group saw a reduction of about 52%. The groups lowered homocysteine at similar rates too. Researchers found no antagonistic effect between the statin and the B vitamins, and all therapies were well tolerated.¹²

So B12 does not boost or blunt the effect of statins. If you need a statin for cholesterol and B12 for a deficiency, there is no reason the two cannot coexist. But do not expect B12 to add meaningful cholesterol reduction on top of what the statin is already doing.

The Fatty Liver Complication

Non-alcoholic fatty liver disease adds an unexpected wrinkle. A genetic analysis using large population datasets found that higher genetically predicted B12 levels were actually associated with increased risk of NAFLD, with a combined odds ratio of about 1.30 per standard-deviation increase in B12. The relationship also ran the other way: genetic liability to NAFLD was associated with higher B12 concentrations.¹³ A separate review confirmed that alterations in B12 and folate levels show a strong correlation with NAFLD severity.¹⁴

This does not mean B12 causes fatty liver. The bidirectional genetic evidence suggests the liver’s handling of B12 is disrupted when liver fat accumulates, and that certain B12-related metabolic pathways may also predispose toward fat deposition. For the cholesterol question, it is a reminder that the B12-lipid relationship is not a simple “more is better” story. The liver is central to both B12 metabolism and cholesterol processing, and when liver health is compromised, both systems can go off the rails in ways that are not easily fixed by a supplement alone.

When Correcting B12 Deficiency Might Actually Help Your Lipids

Pulling together the observational, mechanistic, and trial evidence, here is the practical picture. If your B12 levels are genuinely low, you have a biologically plausible reason to expect that your cholesterol production is running a bit hotter than it should because of disrupted gene regulation. Correcting the deficiency should, in principle, restore normal methylation patterns and dial back that excess production. The populations where this is most likely to matter are:

Vegans and vegetarians: High rates of deficiency, already advised to supplement for other reasons.
Metformin users: Drug-induced depletion, especially over years of use.
Older adults: Declining B12 absorption is common after age 60 due to reduced stomach acid production.
People who have had gastric surgery: Reduced intrinsic factor production impairs B12 uptake.

For these groups, getting B12 levels into the normal range is good practice regardless, and a subtle improvement in lipid markers would be a welcome side effect. But if your B12 levels are already healthy, adding a supplement on top of that has shown no cholesterol-lowering effect in any randomized trial to date. The vitamin is not a statin alternative, a statin booster, or a lipid-lowering hack. It is a nutrient whose absence can create metabolic problems, including lipid problems, and whose presence at normal levels is simply unremarkable in the cholesterol department.