What Happens If You Stop Taking Vitamin B?

January 3, 2026 •

4 min read

According to the National Institutes of Health, vitamin B deficiencies are most common among older adults, pregnant individuals, and those with certain medical conditions. Therefore, understanding what happens if you stop taking vitamin B is crucial, as the effects can range from mild fatigue to serious neurological and psychological issues.

Quick Summary

Discontinuing vitamin B supplements can lead to a range of deficiency symptoms, including fatigue, cognitive impairment, mood changes, and nerve issues, particularly for individuals with specific dietary restrictions or absorption problems. The onset and severity of these symptoms depend on the specific B vitamin and the body's storage levels.

Key Points

Symptom Onset: Deficiency symptoms can appear weeks to years after stopping, depending on the specific B vitamin and the body's storage capacity.
Neurological Risks: Untreated deficiencies, particularly B12, can lead to serious and potentially irreversible nerve damage, memory loss, and cognitive decline.
Mood and Energy: Expect increased fatigue, weakness, and potential mood changes like irritability or depression, as B vitamins are essential for energy metabolism and brain function.
High-Risk Groups: Vegans, older adults, and those with certain digestive disorders are most vulnerable to deficiency after discontinuing supplements.
Consult a Doctor: It is critical to speak with a healthcare professional before stopping supplements, especially if you have a known deficiency or underlying condition.
Consider Dietary Adjustments: For individuals stopping supplements, incorporating more B-rich foods like meat, fish, eggs, and fortified cereals can help maintain adequate levels.

Understanding the B Vitamins and Their Function

Before delving into the consequences of cessation, it is vital to understand the roles of the eight individual B vitamins. As a water-soluble group, with the exception of B12 which is stored in the liver, your body does not retain large reserves of most B vitamins, requiring a consistent daily intake. When you stop taking vitamin B, your body quickly depletes its usable supply of the non-stored B vitamins, while B12 reserves can last for years.

The Roles of Key B Vitamins

Thiamine (B1): Essential for converting food into energy and maintaining a healthy nervous system.
Riboflavin (B2): Important for energy production and maintaining healthy skin, eyes, and the nervous system.
Niacin (B3): Supports energy conversion, skin health, and nervous system function.
Pantothenic Acid (B5): Helps the body release energy from food and supports mental performance.
Pyridoxine (B6): Involved in using and storing energy from carbohydrates and protein and helps form hemoglobin.
Biotin (B7): Helps the body process carbohydrates, fats, and proteins.
Folate (B9): Crucial for forming healthy red blood cells and preventing neural tube defects in unborn babies.
Cobalamin (B12): Vital for nerve and blood cell health, and creating DNA.

Immediate and Short-Term Effects of Stopping Vitamin B

For most healthy individuals who get enough B vitamins from their diet, stopping a supplement may cause no immediate or noticeable side effects. However, for those with pre-existing dietary deficiencies or absorption issues, symptoms can appear within weeks to months. The initial effects are often subtle and can include:

Fatigue and Weakness: Since B vitamins are critical for energy production, a drop in levels can lead to feelings of extreme tiredness and lethargy.
Mood Changes: B vitamin deficiencies, particularly B6 and B12, are linked to mood swings, irritability, and depression.
Cognitive Issues: Problems with memory, concentration, and general confusion can emerge due to the B vitamins' role in brain function.
Digestive Problems: Nausea, diarrhea, and constipation can arise from disruptions in the digestive processes that B vitamins help regulate.
Skin and Mouth Issues: A sore, red tongue, mouth ulcers, or skin rashes are common signs of deficiencies in vitamins B2, B3, B6, and B12.

Long-Term Risks and Complications

If left untreated, a persistent deficiency can lead to more severe and long-lasting health problems. The risks of long-term deficiency vary by the specific vitamin but often include serious neurological and hematological conditions.

Comparison of Deficiency Consequences (B12 vs. Folate)


Feature	Vitamin B12 Deficiency	Folate (B9) Deficiency
Symptom Onset	Gradual, often taking years due to liver stores.	Can appear more quickly, within months, as body stores are smaller.
Neurological Impact	Significant risk of permanent nerve damage, pins and needles, memory loss, and coordination problems.	Less severe neurological symptoms, though can cause irritability and cognitive changes.
Anemia Type	Megaloblastic anemia, where red blood cells are abnormally large and don't function properly.	Megaloblastic anemia, similar to B12 deficiency.
Mental Health	Can lead to severe psychological symptoms, including depression, paranoia, and dementia.	Associated with depression and cognitive impairment.
Pregnancy Risk	Increased risk of neural tube defects in the baby.	Higher risk of neural tube defects like spina bifida.

Who Is Most at Risk?

Certain individuals face a higher risk of developing a deficiency if they stop taking vitamin B supplements. These include:

Vegans and Vegetarians: B12 is found primarily in animal products, making supplementation essential for those following a strict plant-based diet.
Older Adults: Many older individuals have reduced stomach acid, which can hinder the absorption of vitamin B12.
People with Digestive Disorders: Conditions like Crohn's disease, celiac disease, or a history of gastric surgery can impair the body's ability to absorb B vitamins effectively.
Individuals with Alcohol Use Disorder: Excessive alcohol consumption can damage the digestive system and lead to vitamin deficiencies.

How to Safely Discontinue B Vitamins

For most people who take B vitamins as a general wellness supplement and already have a balanced diet, stopping is unlikely to cause major issues. However, if you have a known deficiency or an underlying condition, it is crucial to consult a healthcare provider before stopping. Your doctor can recommend a gradual tapering schedule and check your vitamin levels through a blood test to ensure a smooth transition and prevent relapse.

For those needing to address a deficiency, increasing dietary intake of B-rich foods can often help. For example, folate is found in leafy greens and legumes, while B12 is plentiful in meat, fish, eggs, and fortified cereals.

Conclusion

When you stop taking vitamin B, the outcome depends on your individual health, diet, and the specific B vitamin in question. While a healthy, well-nourished person may experience no adverse effects, those with dietary restrictions or underlying health conditions face a significant risk of developing or relapsing into a deficiency. Early signs often include fatigue, mood changes, and digestive issues. However, if left untreated, severe deficiency can lead to serious neurological damage and other complications. Always consult a healthcare professional before making significant changes to your supplement regimen to ensure your nutritional needs are being met safely and effectively.

Visit the Cleveland Clinic for more detailed information on Vitamin B12 deficiency.

Frequently Asked Questions

The first signs of stopping vitamin B supplements can include fatigue, a drop in energy levels, weakness, and potential mood changes such as irritability or depression. These symptoms may appear gradually over several weeks to months, depending on the specific B vitamin and your body's reserves.

For most healthy people with a balanced diet rich in meat, fish, dairy, and fortified grains, stopping a vitamin B supplement is unlikely to cause a deficiency. The exception is B12, which is stored in the liver for years, so symptoms would take longer to appear.

Because the body, particularly the liver, can store a significant amount of vitamin B12, it can take anywhere from a few months to several years for deficiency symptoms to manifest after you stop supplementation.

Neurological damage from a prolonged vitamin B deficiency, especially B12, can be severe and potentially irreversible if left untreated for too long. Early diagnosis and treatment are crucial for the best chance of recovery.

Vegans and vegetarians are at high risk for B12 deficiency since it is not naturally found in plant-based foods. They should not stop B12 supplementation without consulting a doctor and should either continue supplements or focus on B12-fortified foods to avoid potential neurological and health problems.

For individuals with a pre-existing deficiency or underlying health conditions, stopping B complex supplements 'cold turkey' is not recommended and can cause a rapid return of symptoms. A gradual tapering and consultation with a healthcare provider is the safest approach.

Stopping folate or folic acid supplements during or before pregnancy significantly increases the risk of the baby developing serious birth defects, such as spina bifida. Pregnant individuals are strongly advised to continue supplementing as directed by their doctor.