Can I Take Vitamin B12 with Praluent (Alirocumab)?

The Short Answer: No Interaction Between Vitamin B12 and Praluent

Taking vitamin B12 alongside Praluent (alirocumab) does not raise any clinically meaningful drug-supplement interaction concern. Alirocumab is a fully human monoclonal antibody that works by binding proprotein convertase subtilisin/kexin type 9 (PCSK9) in the bloodstream, blocking LDL receptor degradation so that more LDL cholesterol gets cleared from circulation. Vitamin B12 (cobalamin) is a water-soluble vitamin that is absorbed through intrinsic factor in the gut, stored in the liver, and metabolized through pathways that have no known crossover with alirocumab's mechanism.

No published pharmacokinetic studies, case reports, or major drug-interaction databases, including the Natural Medicines Comprehensive Database, identify a direct interaction between alirocumab and any form of vitamin B12 (cyanocobalamin, methylcobalamin, adenosylcobalamin, or hydroxocobalamin). You do not need to separate doses, reduce the amount of either product, or choose one over the other.

The more clinically relevant question is the one sitting behind this search: why are you asking? If you are on Praluent and also taking metformin, for PCOS, insulin resistance, prediabetes, or type 2 diabetes, that metformin-B12 relationship deserves real attention.

How Alirocumab Works (and Why It Does Not Touch B12 Pathways)

Mechanism of Action

Alirocumab is a subcutaneous injectable biologic given every two weeks at 75 mg or 150 mg, or every four weeks at 300 mg. It targets PCSK9, a protein secreted by the liver that normally marks LDL receptors for destruction. By blocking PCSK9, alirocumab preserves LDL receptors on liver cells, lowering circulating LDL-cholesterol by approximately 50 to 60 percent compared with placebo in the ODYSSEY LONG TERM trial.

Why No B12 Interaction Exists

Monoclonal antibodies like alirocumab are not processed through cytochrome P450 enzymes. They are broken down by proteolysis into peptides and amino acids, exactly like any other protein in your body. Vitamin B12 is absorbed via the ileal intrinsic factor receptor (cubam), stored in the liver, and participates in methionine synthesis and odd-chain fatty acid oxidation. These two pathways never intersect. There is no shared transporter, no enzyme competition, and no overlapping receptor.

This is not an evidence gap. It is a mechanistic non-issue, and it is consistent with how all approved PCSK9 inhibitors (alirocumab and evolocumab) behave with water-soluble vitamins.

The Real B12 Story for Women on Praluent: Metformin

This is where the clinical picture gets genuinely important for a large subset of women reading this.

Who Takes Both Praluent and Metformin?

Women with PCOS are prescribed metformin more than any other non-insulin medication, with up to 30 to 40 percent of women with PCOS using metformin for insulin resistance or cycle regulation. Women with PCOS also carry a significantly elevated cardiovascular risk profile, including dyslipidemia, that may eventually warrant a PCSK9 inhibitor. Women with type 2 diabetes or prediabetes who have established atherosclerotic cardiovascular disease (ASCVD) are another group where metformin and alirocumab co-prescribing is entirely plausible.

If you are in either group, the B12 question is not about alirocumab at all. It is about metformin.

How Metformin Depletes Vitamin B12

Metformin interferes with the calcium-dependent binding of the intrinsic factor-B12 complex to the cubam receptor in the terminal ileum. Long-term metformin use reduces serum B12 by a clinically meaningful margin: a systematic review and meta-analysis published in Diabetes Care found that metformin use was associated with a 19 percent higher prevalence of B12 deficiency compared with placebo. The depletion is dose-dependent and duration-dependent. Women on 2,000 mg per day for more than four years carry the greatest risk.

B12 deficiency causes peripheral neuropathy, megaloblastic anemia, cognitive changes, and elevated homocysteine, a marker that itself carries cardiovascular implications. This matters in a population already managing cardiovascular risk, which is precisely the population taking Praluent.

What to Monitor and When

The following monitoring framework applies specifically to women taking metformin alongside any PCSK9 inhibitor. No published guideline has formalized this combined scenario, so this represents a synthesis of current evidence, applied to the clinical reality of co-prescribing in women.

• Baseline B12 before or at the start of metformin: Serum B12, and ideally methylmalonic acid (MMA), since MMA rises before serum B12 falls and catches functional deficiency earlier.
• Annual B12 check for the first three years of metformin use, then every two years if levels remain stable above 300 pg/mL.
• Supplementation threshold: Most clinicians initiate supplementation when serum B12 falls below 300 pg/mL or when MMA rises above 0.40 micromol/L, even if serum B12 appears borderline.
• Form and dose: Oral crystalline cyanocobalamin 500 to 1,000 mcg daily bypasses the intrinsic factor defect because high-dose oral B12 is absorbed passively in small amounts. This is consistent with the American Diabetes Association Standards of Care, which note that long-term metformin use is associated with B12 deficiency and that periodic measurement should be considered.

Who Is Most Affected: Life-Stage Breakdown

Reproductive Years (Age 18 to 40)

Women in their reproductive years who take metformin for PCOS are the group most likely to be B12-depleted silently. Neurological symptoms of B12 deficiency, including tingling in the hands and feet and fatigue, often get attributed to PCOS symptoms, thyroid dysfunction, or iron deficiency anemia without checking B12. PCOS itself is associated with a higher prevalence of subclinical hypothyroidism and thyroid autoimmunity, adding another layer of diagnostic complexity.

If you are in your twenties or thirties, on metformin for PCOS, and your cardiologist or lipid specialist has now added alirocumab because of familial hypercholesterolemia or premature ASCVD, get a baseline B12 checked now if you have not had one in the past year.

Trying to Conceive (TTC)

B12 adequacy is directly relevant to fertility and early pregnancy. Adequate B12 supports neural tube closure alongside folate. Women with PCOS on metformin who are actively trying to conceive need B12 levels confirmed before stopping contraception. A serum B12 below 200 pg/mL in early pregnancy has been associated with increased neural tube defect risk, though the effect is smaller than that of folate deficiency and the evidence is less definitive.

Perimenopause (Age 40 to 55)

Women approaching menopause have additional reasons to monitor B12. Gastric acid production declines with age, reducing B12 absorption from food. If you are also perimenopausal and on metformin, the cumulative risk of deficiency is real. The cardiovascular risk profile of perimenopause, including rising LDL-cholesterol and decreasing HDL after ovarian estrogen declines, may be the moment when a PCSK9 inhibitor enters the picture. This is the life stage where alirocumab and metformin co-prescribing is most plausible, and the monitoring framework above is most relevant.

Postmenopause

Familial hypercholesterolemia (FH) affects approximately 1 in 250 people, and postmenopausal women with FH who have not reached LDL targets on statins plus ezetimibe are likely candidates for alirocumab. If type 2 diabetes co-exists, metformin continues. Annual B12 monitoring should be part of the cardiometabolic review.

Pregnancy and Lactation Safety (Required Reading if You Are of Childbearing Age)

This section is mandatory for any woman of reproductive age taking alirocumab. Alirocumab is not recommended during pregnancy.

Pregnancy

Alirocumab carries no FDA pregnancy category under the current labeling system, but the prescribing information states that animal reproductive studies showed no adverse developmental outcomes at doses substantially higher than clinical exposures. Human data are essentially absent because women of childbearing potential were excluded or underrepresented in the major ODYSSEY trials.

The clinical guidance, based on the lack of human safety data and on the fact that LDL-cholesterol lowering is not an acute medical necessity during the short window of pregnancy, is to discontinue alirocumab before attempting conception. The drug has a half-life of approximately 17 to 20 days, so stopping at least three to four half-lives before conception (roughly 10 to 12 weeks) allows clearance. Statin use, which is typically a co-prescription, must also be stopped before conception because statins are contraindicated in pregnancy.

If you become pregnant while on alirocumab, discontinue it immediately and contact your prescribing clinician.

Lactation

It is unknown whether alirocumab transfers into human breast milk. Given that monoclonal antibodies are large proteins and are largely degraded in the infant gastrointestinal tract if transferred, theoretical infant exposure is expected to be low. However, no human lactation pharmacokinetic data exist. Until data are available, most clinicians recommend avoiding alirocumab during breastfeeding if alternatives exist for the underlying lipid condition.

Vitamin B12 in Pregnancy and Lactation

Vitamin B12, by contrast, is safe and recommended during pregnancy and breastfeeding. The recommended dietary allowance for B12 rises to 2.6 mcg per day in pregnancy and 2.8 mcg per day during lactation, compared with 2.4 mcg per day for non-pregnant adults. Women following vegan or vegetarian diets or those with prior metformin use should supplement and confirm adequacy before and during pregnancy.

Contraception Requirement

Because alirocumab should not be used in pregnancy and statins (the typical co-therapy) are teratogenic, reliable contraception is required for any woman of childbearing potential who is sexually active and taking either drug. Discuss your contraceptive plan with your prescribing clinician before starting alirocumab.

Female-Specific Conditions Alirocumab Addresses

Familial Hypercholesterolemia in Women

Women with heterozygous familial hypercholesterolemia (HeFH) often go undiagnosed longer than men. Premenopausal estrogen partially masks LDL elevation; after menopause, LDL rises sharply and cardiovascular risk accelerates. The ODYSSEY FH I and FH II trials showed that alirocumab reduced LDL-cholesterol by approximately 49 percent in HeFH patients who remained on maximally tolerated statin therapy.

PCOS and Dyslipidemia

PCOS-associated dyslipidemia typically presents as elevated triglycerides, low HDL, and small dense LDL particles. Alirocumab is not a first-line treatment for PCOS dyslipidemia, but for the subset of women with PCOS plus FH or established ASCVD, it fills an unmet need. The intersection of metformin, PCOS, and alirocumab is exactly where the B12 monitoring framework becomes clinically actionable.

Statin Intolerance in Women

Women report statin-associated muscle symptoms at higher rates than men, with some cohort analyses suggesting a 30 to 50 percent higher rate of myalgia in women on equivalent statin doses. PCSK9 inhibitors offer an alternative or adjunct route to LDL reduction for women who cannot tolerate adequate statin doses. The ODYSSEY OUTCOMES trial, which enrolled patients with recent acute coronary syndrome, showed alirocumab reduced major adverse cardiovascular events by 15 percent versus placebo on a background of high-intensity statin or maximum tolerated statin therapy.

Is Vitamin B12 Supplementation Right for You?

Women Who Should Supplement Proactively

• Women on metformin for more than 12 months at any dose
• Women on metformin at doses of 1,500 mg per day or above, regardless of duration
• Women following a vegan or vegetarian diet
• Women over age 50 (gastric acid declines with age, reducing B12 absorption from food bound forms)
• Women who have had bariatric surgery, which reduces intrinsic factor production
• Women with confirmed serum B12 below 300 pg/mL or elevated MMA

Women Who Do Not Need Extra B12 Solely Because of Praluent

If the only reason you are searching this question is because you started alirocumab and want to know whether it depletes B12 or blocks its absorption, the answer is no. Alirocumab does not affect B12 status. Supplementing B12 when it is not needed does not harm you (excess is renally excreted), but it also does not add cardiovascular benefit.

Choosing a B12 Form

All four forms of B12 are effective for correcting deficiency, though the evidence for clinical superiority of one form over another is thin. Oral cyanocobalamin 1,000 mcg per day is as effective as intramuscular injection for correcting B12 deficiency in most people without severe malabsorption, according to a randomized trial by Kuzminski et al. Methylcobalamin is commonly marketed as superior but has no convincing head-to-head advantage in published randomized data.

Practical Checklist for Women Taking Praluent

• Confirm you are not pregnant before starting or continuing alirocumab.
• Use reliable contraception if you are sexually active and not ready to conceive.
• Ask your clinician to check serum B12 (and MMA if available) if you have been on metformin for more than 12 months.
• Supplement B12 at 500 to 1,000 mcg daily if your level is below 300 pg/mL or if you have been on metformin for more than two to three years.
• No timing separation is needed between your Praluent injection and your B12 supplement.
• Continue annual lipid panels; alirocumab targets LDL-C below 70 mg/dL in high-risk patients and below 55 mg/dL in very-high-risk patients per American Heart Association guidelines.

What the Evidence Gap Looks Like for Women

Women were underrepresented in the foundational alirocumab trials. The ODYSSEY OUTCOMES trial enrolled approximately 40 percent women, which is better than many prior cardiovascular trials but still leaves sex-stratified efficacy and safety data incomplete. The FH trials enrolled a higher proportion of women but were not powered for sex-specific subgroup analysis. The interaction between sex hormones and PCSK9 expression is an active area of investigation: estrogen appears to upregulate PCSK9, which may explain why postmenopausal women see sharper LDL rises than men of the same age. Whether this means postmenopausal women derive greater absolute benefit from PCSK9 inhibition than male counterparts is not yet definitively established. Ask your clinician what the best available data says for your specific risk profile.

"Women with PCOS who are on long-term metformin and now need a PCSK9 inhibitor represent a clinical phenotype that no single trial was designed to study," says Maya Okafor, MD, WomanRx clinical reviewer and board-certified OB-GYN. "The B12 monitoring gap in this group is real, and it is straightforward to close with a single annual lab draw."