Can Statins Cause Vitamin B12 Deficiency?

Current evidence does not support the idea that statins directly cause vitamin B12 deficiency. The apparent link between the two turns out to be a case of mistaken identity: many people who take statins also take metformin, a diabetes drug with a well-documented ability to lower B12 levels. When researchers separate statin users who also take metformin from those who do not, the statin-only group shows no increased risk of B12 deficiency. The confusion is understandable, though, because the overlap between statin and metformin prescriptions is enormous, and the symptoms of B12 deficiency can mimic some common statin side effects.

What the Research Actually Found

A large cross-sectional study of elderly patients looked at statin use and vitamin B12 levels, and the initial numbers seemed to tell a worrying story. Patients using a statin appeared more likely to have B12 deficiency, with an odds ratio of about 1.2. But the picture changed when the researchers dug into who else was taking metformin alongside their statin. Among the more than 1,400 statin users in the study, over 300 were also on metformin. Once those dual-therapy patients were separated out, statin use alone was not associated with B12 deficiency at all. Even after the researchers adjusted for other factors that could muddy the results, statins without metformin showed no meaningful connection to low B12.¹

The combination of a statin and metformin, on the other hand, carried an odds ratio of about 2.6 for B12 deficiency, which was comparable to the risk from metformin on its own. That finding held up whether the researchers looked at raw numbers or corrected for confounders like age and other medications.¹ In plain terms, metformin was doing all the heavy lifting when it came to depleting B12. The statin was just along for the ride.

Why Metformin Gets Confused with Statins

The reason this mix-up persists has less to do with biology and more to do with prescribing patterns. Type 2 diabetes and cardiovascular disease share many of the same risk factors: obesity, high blood pressure, poor cholesterol profiles, and sedentary lifestyles. A huge number of people with type 2 diabetes end up on both metformin (to manage blood sugar) and a statin (to lower cholesterol and reduce heart attack risk). When a person on both drugs develops tingling in their feet or unusual fatigue, they or their doctor may suspect the statin, because statin side effects like muscle pain get more media attention. But B12 deficiency can produce remarkably similar symptoms, and metformin is far more likely to be the cause.

Metformin interferes with B12 absorption in the small intestine, and the effect compounds over time. People who have been on metformin for several years are at higher risk than those who just started. Because B12 stores in the liver can last for years, deficiency often creeps up slowly, arriving well after someone has settled into a stable medication routine. By that point, they may not connect the new symptoms to a drug they have been taking without problems for a long time.

Symptoms That Look Like Statin Side Effects

Part of the confusion stems from the fact that B12 deficiency and commonly reported statin complaints share some territory. Muscle weakness and general fatigue are common early symptoms of low B12. Peripheral neuropathy, the tingling or numbness that often starts in the hands and feet, can occur both with severe B12 deficiency and as a rare side effect of statins themselves. If you are taking a statin and develop these symptoms, a simple blood test for B12 can help sort out what is actually going on before you and your doctor consider changing your statin.

B12 deficiency has additional symptoms that do not overlap with statin complaints, which can help distinguish the two. These include:

Cognitive changes: difficulty concentrating, memory lapses, and in severe cases confusion
Glossitis: a swollen, smooth, reddish tongue
Megaloblastic anemia: fatigue and pallor caused by abnormally large red blood cells
Balance problems: unsteadiness when walking, especially in the dark
Mood changes: depression and irritability that may not have an obvious external trigger

If you are experiencing numbness and tingling alongside any of these additional signs, B12 deficiency moves up the list of likely explanations. This is especially true if you are also taking metformin or follow a diet low in animal products.

The Homocysteine Connection

One reason researchers have explored a possible link between statins and B12 is homocysteine, an amino acid in the blood. Elevated homocysteine levels are a recognized risk factor for cardiovascular disease, and B12 is one of the vitamins the body uses to break homocysteine down. A study of renal transplant recipients taking atorvastatin found that atorvastatin administration was independently associated with circulating homocysteine levels, and that patients with higher B12 and folate levels tended to have lower homocysteine.²

This does not mean atorvastatin was lowering B12. Rather, it highlights that B12 status, folate status, and statin use are all independently bouncing around in the same cardiovascular-risk pool. In people already at risk for heart disease, all three factors tend to be abnormal for different reasons. The interplay between these variables can create statistical associations that look causal at a glance but fall apart when you tease them apart. The study’s more useful takeaway is that maintaining adequate B12 and folate levels matters for keeping homocysteine in check, regardless of whether you take a statin.

What Statins Actually Deplete

While statins do not appear to drain your B12 stores, they do have a well-documented effect on another important molecule: coenzyme Q10, often called CoQ10. CoQ10 plays a role in energy production inside cells, and the same biochemical pathway that statins block to lower cholesterol also reduces the body’s production of CoQ10. Statins block an intermediate step in the synthesis of both cholesterol and CoQ10, which is why lowering one tends to lower the other.³

A meta-analysis of randomized controlled trials confirmed that statin treatment significantly reduces circulating CoQ10 levels compared to placebo. The drop happened regardless of whether the statin was lipophilic or hydrophilic, and it occurred at both lower and higher statin doses.⁴ A separate meta-analysis of placebo-controlled trials found the same pattern across all four types of statins tested, including atorvastatin, simvastatin, rosuvastatin, and pravastatin.⁵

Some researchers have proposed that this CoQ10 depletion could partly explain the muscle pain and fatigue that some statin users experience. The evidence on whether taking CoQ10 supplements actually relieves statin-related muscle symptoms is mixed, but the depletion effect itself is not in doubt. The reason this matters for the B12 question is that people sometimes lump all nutrient-depletion concerns about statins into a single bucket. CoQ10 depletion is real and worth knowing about. B12 depletion from statins alone is not supported by the current data.

Who Should Actually Be Watching Their B12

If statins themselves are not the problem, the practical question becomes: who among statin users should be paying attention to B12? The answer is anyone who has additional, independent risk factors for deficiency. These overlap heavily with the population of statin users simply because of shared demographics.

Metformin users: The biggest red flag. If you take both a statin and metformin, the research suggests your risk of B12 deficiency is roughly two and a half times higher than average, and metformin is the reason.
Older adults: The ability to absorb B12 from food declines with age, partly because stomach acid production drops. Since statins are widely prescribed to older adults, this demographic is overrepresented in both the statin-user population and the B12-deficient population, creating a coincidental overlap.
People on proton pump inhibitors: Long-term use of drugs that suppress stomach acid, taken by many of the same patients who take statins, can also reduce B12 absorption.
People with limited dietary intake of animal products: B12 is found almost exclusively in meat, fish, dairy, and eggs. Vegans and some vegetarians are at inherent risk regardless of what medications they take.
People who have had gastrointestinal surgery: Procedures that alter the stomach or small intestine can reduce the body’s ability to extract B12 from food.

For most statin users without these additional risk factors, routine B12 monitoring is not typically recommended by major medical guidelines. But if you fall into one or more of the groups above, asking your doctor about periodic testing is reasonable.

Getting Tested and What the Numbers Mean

A standard serum B12 blood test is the most common first step. Levels below about 200 pg/mL are generally considered deficient, while levels between 200 and 300 pg/mL fall into a gray zone where some people have symptoms and others do not. If your serum B12 is in that gray zone and you have symptoms that fit, a doctor may order a follow-up test for methylmalonic acid, which rises when B12 is functionally low even if serum levels look borderline acceptable.

Treatment for confirmed deficiency is straightforward. High-dose oral B12 supplements work for most people, though some with absorption problems may need intramuscular injections. If metformin is the underlying cause, supplementation can usually continue alongside the medication without needing to change the metformin prescription. The key is catching the deficiency before it progresses to neurological damage, which can become irreversible if left untreated for too long.

When to Reassess Your Medications

The temptation, when you hear that a medication might be causing a problem, is to stop taking it. With statins, that instinct can be counterproductive. The cardiovascular benefits of statin therapy are well established, and stopping a statin because of a B12 concern that is actually caused by metformin or age-related absorption issues means losing that protection for no reason.

If you develop symptoms that could be B12-related while on a statin, the smarter path is to get tested first. If B12 turns out to be low, look at the full list of medications you take and your dietary habits before pointing the finger at your statin. The real culprits are far more likely to be metformin, a proton pump inhibitor, or simply not eating enough B12-rich foods. If your B12 levels are fine, the symptoms might genuinely be statin-related (muscle soreness and fatigue do occur in a minority of statin users), and that is a separate conversation worth having with your doctor. But conflating the two issues leads to unnecessary medication changes and missed diagnoses.

Why This Misconception Sticks Around

Medical myths about widely used drugs are remarkably durable, and the statin-B12 one has a few features that help it persist. Statins are among the most commonly prescribed medications on the planet, which means millions of people are taking them. With that many users, the sheer number of people who happen to develop B12 deficiency while on a statin is large in absolute terms, even if the rate is no higher than in people not taking statins. It is the same statistical illusion that makes people connect any health change to a recently started medication: the temporal overlap feels causal, even when it is not.

Add to that the documented CoQ10 depletion, and statins develop a general reputation as “nutrient depleting drugs.” Once that label sticks, it is easy for people to extend it to nutrients that statins do not actually affect. Online health forums and supplement marketing sites are particularly prone to listing B12 alongside CoQ10 as nutrients “depleted by statins,” without distinguishing between confirmed and unconfirmed depletions. For the individual trying to make sense of their health, the nuance matters. CoQ10 concerns have solid data behind them. B12 concerns, at least when it comes to statins alone, do not.