Side effects of b12 tablets: Vitamin B-12 Side Effects
Vitamin B-12 Side Effects
Vitamin B-12 Side Effects
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Medically reviewed by Jared Meacham, Ph.
D., RD, PMP, MBA, CSCS — By Emily Cronkleton — Updated on June 8, 2023
Your doctor will give you the right dosage of vitamin B-12 supplement, especially if you will inject it. Taking too much can cause side effects like nausea, headache, dizziness, and in rarely, blood clots or cancer.
Everyone needs vitamin B-12, and most people get enough through their diet. However, it’s important to know what side effects occur when you take too much.
Vitamin B-12 is water-soluble and absorbed in the intestines. After it’s absorbed, it’s used to make DNA and red blood cells. Vitamin B-12 that isn’t being used is stored in the liver. But if you take supplements, you might ingest more than your body needs.
Oral vitamin B-12 is safe to take at recommended doses for healthy people.
Injectable vitamin B-12, which is used to treat significant deficiencies, can cause the following side effects:
- mild diarrhea
- itching
- skin rash
- headache
- dizziness
- nausea
- vomiting
- pulmonary edema and congestive heart failure early in treatment
- vein thrombosis
- sensation of swelling
- polycythemia vera (rare, slow growing blood cancer)
Vitamin B-12 can cause very rare but serious allergic reactions (anaphylaxis).
This includes swelling of the face, tongue, and throat, and difficulty swallowing and breathing. If this occurs after you take vitamin B-12, call 911 or your local emergency services immediately.
Some agents are linked to reduced absorption or serum levels of vitamin B-12. You may need vitamin B-12 supplements if you take any of the following:
- colchicine
- metformin
- proton pump inhibitors
- vitamin C
- chloramphenicol
- h3 blockers
- aminosalicylic acid
Folic acid supplements may interfere with vitamin B-12. Be sure to tell your doctor if you take folic acid.
You may need to take vitamin B-12 separately from the above drugs and supplements — say, one in the morning and one at night — so you can get the full dose of vitamin B-12.
Don’t take vitamin B-12 supplements if you have sensitivities or allergies to vitamin B-12, cobalt, and any other ingredients. Vitamin B-12 is safe to take in recommended dosages if you’re pregnant or breastfeeding.
If you notice any adverse effects after you start taking vitamin B-12 supplements, you should discontinue use immediately. Seek medical attention if your symptoms get worse or are severe.
You can consult your doctor to establish an appropriate dose if it’s determined that you don’t get enough B-12 from food sources.
According to the National Institutes of Health, the recommended dietary amounts (RDAs) are as follows:
- 2.4 micrograms (mcg) daily for ages 14 years or older
- 2.6 mcg daily for pregnant women
- 2.8 mcg daily for breastfeeding women
If you’re over the age of 50, you should try to get your RDA by eating foods with B-12 or by taking a supplement containing 25 to 100 mcg of B-12.
Foods with vitamin B-12 include:
- eggs
- cheese
- fish
- shellfish
- liver
- kidney
- red meat
See your doctor if you have bothersome side effects that don’t go away once you stop taking the supplements.
Avoid taking supplements if possible, and try to get B-12 from food sources.
If you develop any side effects from taking vitamin B-12, you can stop taking the supplement and the symptoms should subside.
After this, you’ll need to determine either an appropriate dose or how to get the vitamin B-12 you need from food sources. You can discuss this with your doctor.
Article resources
- Cyanocobalamin – cyanocobalamin injection. (2023). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a66eb3c4-3e1d-4d49-b963-4fa2334cc9b6
- Vitamin B12: Fact sheet for health professionals. (2022). https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
Last medically reviewed on June 8, 2023
How we reviewed this article:
Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.
Current Version
Jun 8, 2023
Written By
Emily Cronkleton
Edited By
John Bassham
Medically Reviewed By
Jared Meacham, Ph.
D., RD, PMP, MBA, CSCS
Copy Edited By
Copy Editors
Feb 15, 2023
Written By
Emily Cronkleton
Edited By
Frank Crooks
VIEW ALL HISTORY
Share this article
Medically reviewed by Jared Meacham, Ph.D., RD, PMP, MBA, CSCS — By Emily Cronkleton — Updated on June 8, 2023
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- Vitamin B12 Deficiency and Weight Gain — What to Know
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Vitamin B12 deficiency can cause various symptoms, and you may wonder whether weight gain is among them. This article reviews whether a vitamin B12…
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- What Is a Vitamin B-12 Test?
Medically reviewed by Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT
A vitamin B-12 test measures the amount of B-12 in your blood. Find out what your B-12 results mean and how to optimize your B-12 intake.
READ MORE
- Vitamin B12 (folate deficiency anemia) Signs and Symptoms
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Here are nine signs and symptoms of vitamin B12 deficiency.READ MORE
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It’s easier than ever to gain key insights into your health, including possible vitamin and mineral deficiencies.
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Here are nine signs and symptoms of vitamin B12 deficiency.
This is a detailed review of choline and its health effects.Vitamin B-12 Side Effects
Vitamin B-12 Side Effects
- Health Conditions
- Featured
- Breast Cancer
- IBD
- Migraine
- Multiple Sclerosis (MS)
- Rheumatoid Arthritis
- Type 2 Diabetes
- Articles
- Acid Reflux
- ADHD
- Allergies
- Alzheimer’s & Dementia
- Bipolar Disorder
- Cancer
- Crohn’s Disease
- Chronic Pain
- Cold & Flu
- COPD
- Depression
- Fibromyalgia
- Heart Disease
- High Cholesterol
- HIV
- Hypertension
- IPF
- Osteoarthritis
- Psoriasis
- Skin Disorders and Care
- STDs
- Featured
- Discover
- Wellness Topics
- Nutrition
- Fitness
- Skin Care
- Sexual Health
- Women’s Health
- Mental Well-Being
- Sleep
- Product Reviews
- Vitamins & Supplements
- Sleep
- Mental Health
- Nutrition
- At-Home Testing
- CBD
- Men’s Health
- Original Series
- Fresh Food Fast
- Diagnosis Diaries
- You’re Not Alone
- Present Tense
- Video Series
- Youth in Focus
- Healthy Harvest
- No More Silence
- Future of Health
- Wellness Topics
- Plan
- Health Challenges
- Mindful Eating
- Sugar Savvy
- Move Your Body
- Gut Health
- Mood Foods
- Align Your Spine
- Find Care
- Primary Care
- Mental Health
- OB-GYN
- Dermatologists
- Neurologists
- Cardiologists
- Orthopedists
- Lifestyle Quizzes
- Weight Management
- Am I Depressed? A Quiz for Teens
- Are You a Workaholic?
- How Well Do You Sleep?
- Tools & Resources
- Health News
- Find a Diet
- Find Healthy Snacks
- Drugs A-Z
- Health A-Z
- Health Challenges
- Connect
- Breast Cancer
- Inflammatory Bowel Disease
- Psoriatic Arthritis
- Migraine
- Multiple Sclerosis
- Psoriasis
Medically reviewed by Jared Meacham, Ph.
D., RD, PMP, MBA, CSCS — By Emily Cronkleton — Updated on June 8, 2023
Your doctor will give you the right dosage of vitamin B-12 supplement, especially if you will inject it. Taking too much can cause side effects like nausea, headache, dizziness, and in rarely, blood clots or cancer.
Everyone needs vitamin B-12, and most people get enough through their diet. However, it’s important to know what side effects occur when you take too much.
Vitamin B-12 is water-soluble and absorbed in the intestines. After it’s absorbed, it’s used to make DNA and red blood cells. Vitamin B-12 that isn’t being used is stored in the liver. But if you take supplements, you might ingest more than your body needs.
Oral vitamin B-12 is safe to take at recommended doses for healthy people.
Injectable vitamin B-12, which is used to treat significant deficiencies, can cause the following side effects:
- mild diarrhea
- itching
- skin rash
- headache
- dizziness
- nausea
- vomiting
- pulmonary edema and congestive heart failure early in treatment
- vein thrombosis
- sensation of swelling
- polycythemia vera (rare, slow growing blood cancer)
Vitamin B-12 can cause very rare but serious allergic reactions (anaphylaxis).
This includes swelling of the face, tongue, and throat, and difficulty swallowing and breathing. If this occurs after you take vitamin B-12, call 911 or your local emergency services immediately.
Some agents are linked to reduced absorption or serum levels of vitamin B-12. You may need vitamin B-12 supplements if you take any of the following:
- colchicine
- metformin
- proton pump inhibitors
- vitamin C
- chloramphenicol
- h3 blockers
- aminosalicylic acid
Folic acid supplements may interfere with vitamin B-12. Be sure to tell your doctor if you take folic acid.
You may need to take vitamin B-12 separately from the above drugs and supplements — say, one in the morning and one at night — so you can get the full dose of vitamin B-12.
Don’t take vitamin B-12 supplements if you have sensitivities or allergies to vitamin B-12, cobalt, and any other ingredients. Vitamin B-12 is safe to take in recommended dosages if you’re pregnant or breastfeeding.
If you notice any adverse effects after you start taking vitamin B-12 supplements, you should discontinue use immediately. Seek medical attention if your symptoms get worse or are severe.
You can consult your doctor to establish an appropriate dose if it’s determined that you don’t get enough B-12 from food sources.
According to the National Institutes of Health, the recommended dietary amounts (RDAs) are as follows:
- 2.4 micrograms (mcg) daily for ages 14 years or older
- 2.6 mcg daily for pregnant women
- 2.8 mcg daily for breastfeeding women
If you’re over the age of 50, you should try to get your RDA by eating foods with B-12 or by taking a supplement containing 25 to 100 mcg of B-12.
Foods with vitamin B-12 include:
- eggs
- cheese
- fish
- shellfish
- liver
- kidney
- red meat
See your doctor if you have bothersome side effects that don’t go away once you stop taking the supplements.
Avoid taking supplements if possible, and try to get B-12 from food sources.
If you develop any side effects from taking vitamin B-12, you can stop taking the supplement and the symptoms should subside.
After this, you’ll need to determine either an appropriate dose or how to get the vitamin B-12 you need from food sources. You can discuss this with your doctor.
Article resources
- Cyanocobalamin – cyanocobalamin injection. (2023). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a66eb3c4-3e1d-4d49-b963-4fa2334cc9b6
- Vitamin B12: Fact sheet for health professionals. (2022). https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
Last medically reviewed on June 8, 2023
How we reviewed this article:
Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.
Current Version
Jun 8, 2023
Written By
Emily Cronkleton
Edited By
John Bassham
Medically Reviewed By
Jared Meacham, Ph.
D., RD, PMP, MBA, CSCS
Copy Edited By
Copy Editors
Feb 15, 2023
Written By
Emily Cronkleton
Edited By
Frank Crooks
VIEW ALL HISTORY
Share this article
Medically reviewed by Jared Meacham, Ph.D., RD, PMP, MBA, CSCS — By Emily Cronkleton — Updated on June 8, 2023
Read this next
- Vitamin B12 Deficiency and Weight Gain — What to Know
By Alina Petre, MS, RD (NL)
Vitamin B12 deficiency can cause various symptoms, and you may wonder whether weight gain is among them. This article reviews whether a vitamin B12…
READ MORE
- What Is a Vitamin B-12 Test?
Medically reviewed by Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT
A vitamin B-12 test measures the amount of B-12 in your blood. Find out what your B-12 results mean and how to optimize your B-12 intake.
READ MORE
- Vitamin B12 (folate deficiency anemia) Signs and Symptoms
By Jillian Kubala, MS, RD
Vitamin B12 is an important water-soluble vitamin that many people are deficient in.
Here are nine signs and symptoms of vitamin B12 deficiency.READ MORE
- Vitamin B12 Dosage: How Much Should You Take per Day?
By Melissa Groves
The ideal dose of vitamin B12 varies based on your sex, age, and reasons for taking it. This article examines the scientific evidence behind…
READ MORE
- 8 Best Personalized Vitamin Subscription Services of 2023, According to Dietitians
By SaVanna Shoemaker, MS, RDN, LD
Vitamin subscription services not only deliver vitamins to your door but also help you keep track of what to take when. They may even offer…
READ MORE
- What Is Anamu, and Does It Have Benefits?
By Ryan Raman, MS, RD
Anamu is an herb that has long been used in folk medicine to boost immunity, treat various chronic illnesses, and fight inflammation and pain. This…
READ MORE
- What Is Choline? An Essential Nutrient With Many Benefits
By Mary Jane Brown, PhD, RD (UK)
Choline is an essential nutrient that has many benefits for your health.
This is a detailed review of choline and its health effects.READ MORE
- 5 Vitamin Deficiency Tests You Can Order Online, Plus Answers to Common Questions
It’s easier than ever to gain key insights into your health, including possible vitamin and mineral deficiencies.
READ MORE
- What Is Magnesium Malate, and Does It Have Benefits?
By Rachael Ajmera, MS, RD
The mineral magnesium plays a key role in nearly every aspect of your health, and many people take supplements to increase their intake. This article…
READ MORE
- 7 Emerging Benefits of Pueraria mirifica
By Ansley Hill, RD, LD
Pueraria mirifica — or Kwao Krua — has long been used as a rejuvenation therapy in traditional Thai medicine practices. Here are 7 emerging health…
READ MORE
Here are nine signs and symptoms of vitamin B12 deficiency.
This is a detailed review of choline and its health effects.Cyanocobalamin (Vitamin B12) – instructions for use, doses, side effects, reviews of the drug:
Description of the drug in 1998
Date of approval: 07/31/1998
Content
- Active substance
- ATX
- Pharmacological group
- Nosological classification (ICD-10)
- Composition and form of release
- pharmachologic effect
- pharmachologic effect
- Indications
- Contraindications
- Dosage and administration
- Side effects
- Interaction
- Precautionary measures
- Storage conditions
- Best before date
- Reviews
Active ingredient
Cyanocobalamin* (Cyanocobalamin*)
ATX
B03BA01 Cyanocobalamin
Pharmacological group
Stimulants of hematopoiesis
Vitamins and vitamin-like products
Nosological classification (ICD-10)
ICD-10 code list
Composition and formulation
1 ml solution for injection contains cyanocobalamin (vitamin B 12 ) 200 or 500 mcg; in ampoules of 1 ml, in a cardboard box 10 pcs.
Pharmacological action
Pharmacological action –
hematopoietic , stimulating cell metabolism .
Participates in the transfer of methyl fragments, the formation of choline, methionine, creatine, nucleic acids, the maturation of erythrocytes, promotes the accumulation of compounds containing sulfhydryl groups in erythrocytes.
Participates in the transfer of methyl fragments, the formation of choline, methionine, creatine, nucleic acids, the maturation of erythrocytes, promotes the accumulation of compounds containing sulfhydryl groups in erythrocytes.
Indications
Anemia (Addison-Birmer, alimentary macrocytic, iron deficiency,
posthemorrhagic, aplastic, caused by toxic substances and drugs), cirrhosis of the liver,
hepatitis, myelosis, polyneuritis, sciatica, trigeminal neuralgia, amyotrophic lateral sclerosis, children
cerebral palsy, multiple sclerosis, Down’s disease, skin diseases, peripheral nerve injuries.:max_bytes(150000):strip_icc()/inositol-what-should-i-know-about-it-89466-1a6f6de880a14d9190afa5e1b65e647c.png)
Contraindications
Thromboembolism, angina.
Dosage and administration
Information for healthcare professionals only.
Are you a healthcare professional?
S/C, IM, IV and intralumbar.
Addison-Birmer anemia – 100-200 mcg every other day; with Addison-Birmer anemia with symptoms of funicular myelosis and with macrocytic anemia with disorders of the nervous system – 500 mcg or more per injection (daily for the first week, and then with intervals between injections of up to 5-7 days). Simultaneously appoint folic acid. In the period of remission, in the absence of funicular myelosis phenomena, 100 mcg is administered for maintenance therapy 2 times a month, and in the presence of neurological phenomena, 200-400 mcg 2-4 times a month.
For iron deficiency and posthemorrhagic anemia – 30-100 mcg 2-3 times a week; with aplastic anemia (especially in children) – 100 mcg until the onset of clinical and hematological improvement; with alimentary anemia in children at an early age and in premature babies – 30 mcg / day for 15 days.
In diseases of the central nervous system and neurological diseases with pain syndrome, it is administered in increasing doses from 200 to 500 mcg per injection, and when the condition improves, 100 mcg/day; course – up to 2 weeks.
In traumatic lesions of the peripheral nerves – 200-400 mcg every other day for 40-45 days.
For hepatitis and liver cirrhosis, 30–60 mcg per day or 100 mcg every other day for 25–40 days.
With dystrophies in young children, Down’s disease and cerebral palsy – 15-30 mcg every other day.
In case of funicular myelosis, amyotrophic lateral sclerosis, multiple sclerosis, sometimes 15-30 mcg is injected into the spinal canal (gradually increasing the dose to 200-250 mcg).
Side effects
Excitation, pain in the heart, tachycardia, allergic reactions.
Interactions
Information for healthcare professionals only.
Are you a healthcare professional?
Incompatible (in one syringe) with thiamine bromide, riboflavin.
Precautions
In angina pectoris, use with caution and in lower doses.
Storage conditions
In a place protected from light.
Keep out of reach of children.
Expiry date
2 years.
Do not use after the expiry date which is stated on the packaging.
Update date: 04/30/2020
Vitamin B12 – instructions for use, doses, side effects, reviews of the drug: instant tablets, 5000 mcg
0.004 ‰
Analogs
Description selection
| Lec. form | Dosage |
|---|---|
instant tablets | 5000 mcg |
injection | 0. |
2 mg/mlinstant tablets
5000 mcg
injection
0.2 mg/ml
All forms of release, dosages, registration certificates, drug manufacturers, drug characteristics
Product description Vitamin B12 (solution for injection, 0.2 mg/ml) based on the official instructions, approved by the manufacturer in 1998
Date approved: 07/31/1998
Contents
- Active substance
- ATX
- Pharmacological group
- Composition and form of release
- Dosage and administration
- Storage conditions
- Best before date
- Reviews
Active ingredient
Cyanocobalamin* (Cyanocobalamin*)
ATX
B03BA01 Cyanocobalamin
Pharmacological group
Stimulants of hematopoiesis
Vitamins and vitamin-like products
Composition and form of release
1 ampoule with 1 ml solution for injection contains cyanocobalamin 200 or 500 mcg; in a box of 10 pcs.
, complete with ampoule knife.
Dosage and administration
Information for healthcare professionals only.
Are you a healthcare professional?
S/C, IM, IV and intralumbar. For Addison-Birmer anemia (in combination with folic acid)
– 100-200 mcg once a day, for 2 days; with Addison-Birmer anemia with symptoms
funicular myelosis and macrocytic anemia with disorders of the nervous system – 500 mcg and
more per injection (in the first week daily, and then at intervals between injections up to 5-7 days). During
remissions – 100 mcg 2 times a month (maintenance therapy), in the presence of neurological phenomena
(funicular myelosis) – 200-400 mcg 2-4 times a month. With iron deficiency and
posthemorrhagic anemia – 30-100 mcg 2-3 times a week; with aplastic anemia
(especially in children) – 100 mcg until the onset of clinical and hematological improvement; with alimentary
anemia in children at an early age and in premature babies – 30 mcg / day for 15 days.:max_bytes(150000):strip_icc()/vitamin-b12-and-multiple-sclerosis-2440634_FINAL-1f1c3e9232974109b15f5c5c5aa6f120.png)