face with acne
Julie Hambleton
Julie Hambleton
May 16, 2023 ·  5 min read

Do Vitamin B12 Supplements Cause Acne, Bone Fractures, and Lung Cancer?

B12 is a vitamin that’s crucial for your body to function properly. It’s found in animal foods, including meat and fish. People who don’t eat animal products are often advised to take vitamin B12 supplements or use fortified foods to make up for the lack of B12 in their diets. But there are some common misconceptions about this vitamin that you should know before you start taking it.

What Is Vitamin B12?

Vitamin B12 is a water-soluble vitamin that’s essential for many bodily functions. It helps your body make red blood cells, keeps nerves healthy, and supports the immune system. Vitamin B12 also helps make DNA and keeps your brain cells functioning properly. It’s important for pregnant women because it helps prevent birth defects and promotes the development of a healthy baby. (1)

Vitamin B12 comes from a variety of foods, including meat, fish, and dairy products. It’s also found in some plant-based foods like legumes, fortified cereals, and nutritional yeast. In most cases, you don’t have to worry about getting enough vitamin B12. Most people eat a balanced diet that includes foods that contain this important nutrient. There are some exceptions, however, such as vegans and vegetarians who need to be aware of their sources of B12.

What Happens if You Don’t Consume Enough Vitamin B12?

If you don’t get enough vitamin B12, your body can’t make new cells. This means that your body doesn’t grow and repair itself properly, which could lead to pernicious anemia, fatigue, and weakness. It may also cause cognitive issues like memory loss or confusion. The symptoms of a B12 deficiency can be mild or severe. Most people don’t have any symptoms, but there are some warning signs that you may need to increase your intake of this nutrient. (2) Some of the symptoms of a B12 deficiency include:

  • Mild tingling in your hands and feet
  • Fatigue and weakness
  • Memory loss or confusion
  • A sore mouth or tongue
  • A pale and smooth tongue
  • Loss of balance and coordination
  • Feeling dizzy when you stand up from a seated position

If you are experiencing these symptoms, talk to your healthcare practitioner. They can order blood tests to see if your vitamin B12 status is low. If it is, they will likely prescribe you a supplement. Most often, they will start you with an oral supplement; however, if that doesn’t work, they will prescribe you injections.

Read: Mouth warnings to look for if your vitamin B12 levels are low

Vitamin B12, Acne, Bone Fractures, and Cancer

If you regularly keep up with nutrition news or have done a simple internet search on vitamin B12, you may have come across some information that might scare you a bit. These include studies that potentially connect the vitamin to things such as acne, fractures, and even lung cancer. Does this mean that you shouldn’t be taking this supplement, even if you are at risk of deficiency? Let’s clear up some of the confusion.

Does Vitamin B12 Supplementation Cause Acne?

The short answer is: It can, but usually, only injections will cause it. This is because injections are considered megadose, or 5,000 to even 10,000 micrograms per week. Even in those cases, only about 1 out of 10 people will experience vitamin B12 injection-induced acne. This is because Vitamin B12 modulates the gene expression of the skin bacteria that cause acne. In other words, it affects the way your skin bacteria behave. This means that in some cases, vitamin B12 supplementation can cause acne by changing the skin’s environment. However, this is not as common with oral supplementation of vitamin B12 as it is with injections. (3, 4, 5)

Most people who take oral supplements do not experience any side effects, and many who get injections do not experience side effects either. If you do experience acne from taking vitamin B12 supplementation, then it will usually go away once you stop taking the supplement. This can be true even if you’ve been taking it for years.

Read: B vitamins could help treat severe nonalcoholic fatty liver disease

Does vitamin B12 supplementation increase your risk of bone fractures?

This one is not exactly true. High doses of B6 and B12 together were found to increase the risk of hip fractures in postmenopausal women. Other research shows, however, that high doses of B6 do this on their own, and B12 alone had no effect. If you have osteoporosis and are taking B6 and B12 together, then it’s best to check with your doctor before increasing the dose. If you’re healthy, you don’t need to worry about bone fractures. (6, 7)

Does B12 supplementation increase your risk of lung cancer?

A 2017 study found that in men who smoked, there seemed to be an increased risk of lung cancer in those with elevated vitamin b12 status. This might be because those who eat more meat tend to have higher vitamin b12 status. It could be that these men simply were eating more red meat than the others, which is why their vitamin b12 was higher. High consumption of meat, especially red meat, is associated with a higher risk of cancer. If you are not a smoker and have never been diagnosed with lung cancer, then it’s unlikely that your vitamin b12 levels will increase your risk of lung cancer. (8, 9)

The Bottom Line

While some research shows that there could be a connection between Vitamin B12 and acne, bone fractures, and lung cancer, the truth is that most of this research is highly inconclusive. Especially for those who follow a vegan or vegetarian diet, the risks of not supplementing their diet likely outweigh those of supplementation. As always, before starting a new supplement, speak with your health care provider and check your current vitamin status to ensure it is something you need.

Keep Reading: Vitamin B12 Deficiency and Dementia Symptoms: What You Should Know


  1. Vitamin B-12.” Mayo Clinic
  2. Vitamin B12 deficiency from the perspective of a practicing hematologist.” Pubmed. Ralph Green. May 2017.
  3. Vitamin B-12 induced acnes.” Pubmed. A Dupré, et al. August 1979.
  4. Vitamin B12 modulates the transcriptome of the skin microbiota in acne pathogenesis.” Pubmed. Dezhi Kang , et al. June 2015.
  5. Acneiform eruption due to “megadose” vitamins B6 and B12.” Pubmed. E F Sherertz. 1991.
  6. B Vitamins and Hip Fracture: Secondary Analyses and Extended Follow-Up of Two Large Randomized Controlled Trials.” Pubmed. Maria Garcia Lopez, et al. October 2017.
  7. Vitamin B12, folate, homocysteine, and bone health in adults and elderly people: a systematic review with meta-analyses.” Pubmed. J P van Wijngaarden, et al. February 2013.
  8. Long-Term, Supplemental, One-Carbon Metabolism-Related Vitamin B Use in Relation to Lung Cancer Risk in the Vitamins and Lifestyle (VITAL) Cohort.” Pubmed. Theodore M Brasky, et al. August 22, 2017.