Does Vitamin B12 Prevent Canker Sores? (Or Cure Them?)


Vitamin B12 is known for having wide-reaching effects on the nervous system.

But more and more research is showing that consuming vitamin B12-rich sources (or taking vitamin B12 supplementscan help prevent or even cure canker sores.

I’m going to summarize that research in this short post so that you understand if it’s worth

Does Vitamin B12 Prevent Cankers or Heal Them?

Let’s start with a study that lasted 6 months in a population of people with recurrent aphthous stomatitis (fancy name for recurring canker sores). Subjects were split into a control (placebo) group and an intervention group that consumed a 1000 mcg tablet of vitamin B12 per day, which isn’t a particularly high dose (1).

It took until the 5 month point to see a significant difference in the 2 groups, suggesting that people with recurring cankers are more likely to be deficient in B12. But the results were impressive:

During the last month of treatment a significant number of participants in the intervention group (who took B12) reached “no aphthous ulcers status” (74.1% vs 32.0%; P < .01).

For something so cheap and easy like taking a B12 supplement once a day, those results are great.

The graphs below shows that not only did the group that took B12 have fewer cankers in the 5th and 6th months (by a large margin), but their cankers also went away much faster (they lasted about half as long).

graph showing that taking vitamin b12 reduced cankers after 5 months of daily usage

This suggests that taking vitamin B12 tablets not only prevented the canker sores, but also made them less severe.

Other research that reviewed all the different ways to treat canker sores found that Amlexanox 5% paste is the most effective option, but it’s not easy to get over the counter in most countries (2). Your doctor may prescribe it if you have frequent canker sores.

The more interesting finding from that research was that oral vitamin B12 supplements and avoiding toothpastes containing sodium lauryl sulfate are the two most convenient ways of preventing cankers that have decent evidence behind them.

Side note for this research: Almost all research on this topic is done on subjects taking a B12 supplement. In theory, it shouldn’t matter if you get B12 from food or a supplement, but it’s possible that it makes a difference in this specific case.


There’s a decent amount of research showing that long-term vitamin B12 supplementation can reduce the frequency and severity of cankers in those that suffer from recurring canker sores.

Can Vitamin B12 Deficiency Cause Cankers?

The earlier research showed that it took until the 5 month mark for the group taking vitamin B12 supplements to see a statistically significant reduction in canker sores. This may suggest that having a B12 deficiency is at least partly responsible for the sores.

Other research has shown that those with a lower regular intake of vitamin B12 are more likely to have recurring canker sores (3).

Will Vitamin B12 Help Anyone With Canker Sores?

Let’s be clear – While vitamin B12 has a neutral or positive effect on canker sores, it’s not a miracle medication in most cases.

A vitamin B12 deficiency (or low intake) is only one possible cause of canker sores.

If canker sores are caused by something different, it’s unlikely that extra vitamin B12 will have much of an effect (although you should still get the recommended daily amount).

Other causes of canker sores include:

  • Stress – Research shows that stressful life events often trigger canker sore outbreaks (4). Mental stress is more of an issue than physical stress.
  • Mouth injury – Any injury to the inside of the mouth is likely to result in a canker sore. The most common causes are dental fixtures like braces or biting the inside of your mouth while eating.
  • Acidic foods – Studies have shown that acidic foods (e.g. citrus) increases the risk of developing cankers (5).
  • Certain drugs – While a bit ironic, anti-inflammatory drugs like ibuprofen (i.e. Advil) will reduce the pain of canker sores, but also makes it more likely to develop them (6).
  • Sodium lauryl sulfate – This is a common ingredient in many popular toothpastes that triggers frequent canker sores in a significant amount of the population (yours truly included) (7). Finding a different toothpaste without it often helps those with frequent cankers (Tom’s is a good brand).

So while a vitamin B12 deficiency may be the root cause of cankers for some people, it’s important to evaluate each individual case and see if any of the above factors may also need to be addressed.

About the author

Dale Cudmore

Your friendly neighborhood vegan from Toronto. Chemical engineer turned semi-professional soccer player and freelance nutrition writer. I've been vegan for years and try to make life easier for others by sharing what I've learned.