What Happens When You Stop Taking B12 Supplements?: A Guide to the Risks and Re-emerging Symptoms

October 8, 2025 •

4 min read

It is a surprising fact that the body can store Vitamin B12 in the liver for several years, with stores potentially lasting 3 to 5 years. This long storage period means that when you stop taking B12 supplements, symptoms of deficiency may not reappear immediately, leading to a false sense of security.

Quick Summary

When ceasing B12 supplements, individuals with an underlying deficiency will eventually see symptoms return, though this can take a significant amount of time due to the body's storage capacity. The timeframe depends on initial B12 levels, dietary intake, and the specific reason for supplementation.

Key Points

Delayed Symptoms: Symptoms of B12 deficiency may take months or even years to reappear after stopping supplementation, thanks to the body's liver stores.
Neurological Risks: Untreated B12 deficiency can lead to permanent nerve damage, resulting in persistent tingling, numbness, and balance issues.
Consult a Doctor: Never stop B12 supplements abruptly without consulting a healthcare provider, especially if you have a chronic condition like pernicious anemia or malabsorption issues.
Return of Anemia: For those with B12 deficiency anemia, stopping treatment will cause the anemia and its associated fatigue and weakness to return.
High-Risk Groups: Individuals on vegan/vegetarian diets, older adults, and those with GI conditions often require lifelong supplementation to maintain adequate B12 levels.
Subtle Onset: The gradual return of symptoms means they can be mistaken for other conditions or simple aging, delaying necessary treatment and increasing the risk of complications.
Blood Monitoring: Regular blood tests are necessary for individuals who require B12 supplementation to confirm levels are adequate and to detect any drops before symptoms re-emerge.

The Gradual Re-emergence of B12 Deficiency

Vitamin B12 is a vital nutrient crucial for several bodily functions, including nerve health and red blood cell production. For individuals who require supplementation due to malabsorption issues, diet, or other medical conditions, stopping this treatment can have significant consequences. Unlike many other water-soluble vitamins that are quickly excreted, B12 is stored efficiently in the liver, which acts as a reserve. This storage capacity means that stopping supplementation does not cause an immediate crash in B12 levels. Instead, the effects can emerge slowly over months or even years, making the cause of returning symptoms easy to overlook.

Why Do People Stop Taking Supplements?

People might decide to stop taking vitamin B12 supplements for a variety of reasons, not all of them medically sound. Some common justifications include:

Symptom Resolution: After feeling better, some people mistakenly believe their deficiency is permanently cured and that they no longer require supplementation.
Feeling Healthy: The long period of symptom-free living due to B12 reserves can create a false sense of security that the problem has been resolved. The slow return of symptoms, which can mimic normal aging, further reinforces this misconception.
Dietary Changes: Some individuals may attempt to manage their B12 intake solely through diet, which is insufficient for those with malabsorption issues.
Lack of Awareness: For some, it may simply be a matter of forgetting to take the supplement or not understanding that their underlying condition requires lifelong management.

The Timetable for Symptom Recurrence

The exact time it takes for B12 deficiency symptoms to return after stopping supplementation varies significantly between individuals. Factors include the initial severity of the deficiency, the length of treatment, and the body's intrinsic storage capacity. Generally, the timeline is not immediate.

Weeks to Months: For those with limited B12 stores, especially if they have an ongoing malabsorption problem, symptoms could begin to return within weeks or months.
Years: For those with a large reserve in the liver, it could take several years before symptoms become noticeable again.

What to Expect When Symptoms Return

The symptoms that reappear after stopping B12 supplementation are the same ones experienced during the initial deficiency, but they can gradually intensify over time. The following is a list of common symptoms:

Neurological Changes: A lack of B12 can affect the nervous system, causing tingling (pins and needles) in the hands and feet, numbness, muscle weakness, and problems with balance.
Anemia and Fatigue: As red blood cell production falters, anemia can return, leading to extreme tiredness, lack of energy, and shortness of breath.
Cognitive Difficulties: B12 is important for brain function. Deficiency can cause memory loss, confusion, and other cognitive issues.
Psychological Problems: Mood changes, including depression, anxiety, and in severe cases, more serious psychological disturbances, can return.
Gastrointestinal and Physical Signs: A swollen, red tongue (glossitis), mouth ulcers, and pale or yellowed skin can also signal a returning deficiency.

A Comparison of Deficiency and Corrected States

To highlight the impact of stopping B12 supplements, consider the differences between a corrected state and a returning deficiency:


Feature	When Taking B12 Supplements (Corrected)	After Stopping B12 Supplements (Deficient)
Energy Levels	Normal, reduced fatigue.	Extreme tiredness (fatigue) and lethargy.
Neurological Symptoms	Reduced or resolved tingling, numbness.	Pins and needles, memory issues, unsteady gait (ataxia).
Psychological State	Stable mood, reduced anxiety.	Depression, confusion, irritability, or other psychological problems.
Physical Signs	Healthy skin tone, no glossitis.	Pale or yellowed skin, swollen red tongue, mouth ulcers.
Cognitive Function	Clear thinking, better memory.	Memory loss, difficulty thinking and reasoning.

The Critical Importance of Medical Guidance

Stopping B12 supplementation, especially if it was prescribed for a diagnosed deficiency, should never be done without consulting a healthcare provider. This is particularly true for individuals with conditions like pernicious anemia, where the body cannot absorb B12 from food and requires lifelong treatment. Attempting to manage B12 levels on your own is risky and can lead to a gradual but serious decline in health. For certain at-risk populations, ongoing supplementation is a necessity, not a temporary fix.

Conclusion: The Long-Term Consequences of Neglect

While the body’s ability to store vitamin B12 provides a buffer, it is not an excuse to stop supplementation without medical advice. The risks associated with a recurring deficiency, particularly the potential for irreversible neurological damage, are too significant to ignore. If you have been diagnosed with a B12 deficiency and are considering discontinuing your supplements, speak with your doctor. Regular blood tests are essential to monitor your B12 levels and ensure that you are maintaining the appropriate nutritional status to avoid the long-term, damaging effects of deficiency.

National Institutes of Health (NIH) Office of Dietary Supplements

Frequently Asked Questions

The time it takes for symptoms to return varies based on individual factors, but due to the body's ability to store B12, it can take several months to years. For those with underlying malabsorption issues, symptoms may reappear more quickly.

No, stopping B12 supplements does not cause withdrawal symptoms in the traditional sense. Any negative effects experienced are simply the return of the underlying B12 deficiency symptoms that the supplements were managing.

Early signs of a returning B12 deficiency can include fatigue, a lack of energy, and subtle neurological symptoms like tingling or numbness in the extremities.

For most individuals with a diagnosed B12 deficiency, especially those with malabsorption issues, switching to a diet alone is not enough to maintain adequate levels. Always consult your doctor before making any changes to your treatment plan.

Some nerve damage caused by a B12 deficiency can be improved with appropriate treatment, but if the deficiency is left untreated for an extended period, the damage can become permanent.

If you have pernicious anemia and stop taking B12 supplements or injections, the anemia and its associated symptoms will return. Without a functioning intrinsic factor, you will not absorb B12 from food, making lifelong supplementation necessary.

The only reliable way to know if your B12 levels are adequate is through blood tests ordered by a healthcare provider. Self-assessment based on symptoms is unreliable due to the delayed onset and subtle nature of the deficiency.

Yes, older adults are often at higher risk for B12 deficiency and are more susceptible to its negative effects, especially neurological problems. Stopping supplementation without medical oversight is particularly dangerous for this population.