Do People with ADHD Need More B12? Exploring the Connection

November 16, 2025 •

2 min read

A systematic review and meta-analysis found that children with ADHD often have significantly lower levels of vitamin B12 compared to their healthy peers. This finding has prompted a key question for many families and individuals: Do people with ADHD need more B12, or is the observed correlation a symptom of other underlying issues?

Quick Summary

Studies show a consistent link between lower vitamin B12 and ADHD, though this is not a causal relationship. Supplementation is not a primary treatment but can help individuals with diagnosed deficiencies.

Key Points

Correlation, Not Causation: Studies show a correlation between lower B12 levels and ADHD, but this doesn't mean deficiency causes ADHD.
Not a Primary Treatment: B12 supplementation should not replace standard ADHD treatments like medication and therapy.
Testing is Key: It's crucial to get B12 levels tested by a healthcare provider to confirm a deficiency before starting supplements.
Addresses Overlapping Symptoms: For those with a confirmed deficiency, B12 supplementation can help alleviate overlapping symptoms like fatigue, low mood, and memory issues.
Affects Neurotransmitter Function: B12 is vital for producing neurotransmitters like dopamine and serotonin, which play a key role in ADHD.
Dietary Sources are Preferable: For those without a diagnosed deficiency, focusing on a diet rich in B12 from animal products or fortified foods is the recommended approach.
Elevated Homocysteine: A B12 deficiency can lead to high homocysteine levels, a neurotoxic substance often found to be elevated in ADHD patients.

The Scientific Link Between B12 and ADHD

Vitamin B12 is essential for nerve function and producing neurotransmitters. Research indicates individuals with ADHD often have lower B12 levels than those without the condition. Some studies also suggest an inverse relationship between B12 levels and the severity of certain ADHD symptoms.

The Role of Metabolism and Homocysteine

One proposed link involves B12's role in one-carbon metabolism, crucial for synthesizing neurotransmitters. B12 helps convert homocysteine to methionine; deficiency can lead to elevated homocysteine. Studies show ADHD patients often have lower B12 and higher homocysteine levels. High homocysteine is linked to neurotoxicity, potentially contributing to ADHD symptoms.

Recognizing B12 Deficiency Symptoms

Many B12 deficiency symptoms can resemble or overlap with ADHD symptoms, making diagnosis complex.

Common physical symptoms of B12 deficiency include:

Fatigue or weakness
Tingling or numbness
Difficulty with coordination
Sore tongue
Pale or jaundiced skin

Common neurological and psychological symptoms include:

Memory and cognitive problems
Depression or irritability
Confusion or difficulty concentrating
Mood swings
Insomnia

Diagnosing and Treating B12 Deficiency in ADHD Patients

Distinguishing between B12 deficiency and ADHD is important, as they require different treatments. A blood test can measure B12 levels and markers like homocysteine and methylmalonic acid to diagnose a deficiency.

Comparison Table: B12 Supplementation for ADHD


Feature	B12 Supplementation for Confirmed Deficiency	B12 Supplementation Without Confirmed Deficiency
Efficacy	Can alleviate overlapping symptoms like fatigue and cognitive issues.	No strong evidence suggests improvement in core ADHD symptoms.
Purpose	To correct a nutritional deficit that may be exacerbating ADHD-like symptoms.	Unlikely to resolve ADHD symptoms if no underlying deficiency exists.
Medical Advice	Recommended under medical supervision to determine proper dosage and form (e.g., oral, sublingual, injection).	Not recommended as a primary treatment and should not replace standard ADHD therapy.
Associated Benefit	Potential for noticeable improvement in energy, concentration, and mood.	Unlikely to provide additional benefits beyond basic nutritional needs.

Should You Supplement with B12?

For most people with ADHD without a B12 deficiency, supplementation is unlikely to significantly improve symptoms. However, individuals with risk factors, such as restrictive diets (vegan/vegetarian), malabsorption issues, or certain medications, should consider testing.

Focusing on dietary sources of B12 is recommended first. Since B12 is found in animal products, those with dietary restrictions need to be particularly aware. Good sources include:

Meat and fish
Eggs
Dairy products
Fortified foods

Conclusion: The Final Takeaway

While research shows a correlation between lower B12 and ADHD, particularly in children, it's not a simple cause-and-effect. B12 deficiency and ADHD have overlapping symptoms, and treating a confirmed deficiency can help with issues like fatigue and cognitive impairment. However, B12 supplements are not a substitute for standard ADHD treatments and require medical guidance. Consulting a healthcare provider for testing before supplementing is crucial. Addressing nutritional deficiencies can be a helpful addition to an ADHD management plan, but it is not a cure.

For more information on the biochemical markers associated with ADHD, including B12, you can read the study published in MDPI.

Frequently Asked Questions

No, vitamin B12 is not a cure for ADHD. It is a vital nutrient for brain function, and while correcting a deficiency might help with some overlapping symptoms like fatigue or concentration issues, it does not treat the core neurodevelopmental aspects of ADHD.

The only way to know for certain is to have your B12 levels tested by a doctor. Some symptoms of deficiency, such as fatigue, memory issues, and mood swings, can mimic or worsen ADHD symptoms, but a blood test is required for a definitive diagnosis.

No, vitamin B12 supplementation should not replace any prescribed ADHD medication. It is considered an adjunctive therapy for individuals with a confirmed deficiency and should be used alongside—not in place of—conventional, evidence-based treatments.

Vitamin B12 is generally considered safe, even at high doses, because it is water-soluble and the body excretes excess. However, excessive amounts are not proven to provide extra benefits and can potentially cause side effects. Always follow medical guidance on dosage.

Primary risk factors for B12 deficiency include having a restrictive diet (like vegan or vegetarian), issues with malabsorption (e.g., from bariatric surgery or certain stomach conditions), and older age. Certain medications can also interfere with B12 absorption.

Yes, since B12 is primarily found in animal products, a strict vegetarian or vegan diet is a significant risk factor for deficiency. This means individuals with ADHD who follow these diets are at a higher risk of low B12 and should be vigilant about testing and supplementation.

Homocysteine levels rise when B12 is deficient because the vitamin is needed to metabolize it. High homocysteine is neurotoxic and can cause oxidative stress, potentially contributing to the neurological challenges and symptoms experienced by people with ADHD.