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#sahabatpramita, have you heard that recurring canker sores always mean the body lacks vitamin C? The idea sounds reasonable because vitamin C supports tissue repair. However, scientific evidence does not identify vitamin C deficiency as the main cause of recurrent mouth ulcers.

Recurrent aphthous stomatitis, or canker sores that repeatedly appear inside the mouth, is considered a multifactorial condition. Research has linked it with immune responses, stress, minor mouth injuries, genetic factors, and nutrient deficiencies. One ulcer pattern therefore cannot be traced to one vitamin without assessment.

A 2024 systematic review and meta-analysis combined 22 studies examining blood-related nutrients in people with recurrent canker sores. Among vitamin B12, ferritin, folate, iron, and zinc, vitamin B12 deficiency showed the strongest association. People with low vitamin B12 were nearly three times more likely to be in the recurrent canker sore group than healthy controls. Low ferritin, which reflects reduced iron stores, showed the next strongest association at about 2.5 times.

These numbers show an association, not proof that low vitamin B12 directly causes every episode. The researchers also stated that the role of vitamin B12 deficiency remains unknown. Therefore, saying “recurring canker sores are caused by vitamin C deficiency” is a myth when presented as a universal explanation.

What about vitamin C? A study involving 16 children reported that vitamin C treatment was linked with a 50 percent reduction in ulcer outbreaks and lower pain levels. However, the authors called the findings preliminary and recommended larger randomized trials. The study tested whether vitamin C could ease symptoms; it did not prove that participants had vitamin C deficiency.

When canker sores keep returning, taking high-dose supplements without checking the underlying problem may miss the real issue. Depending on a healthcare professional’s assessment, testing may include vitamin B12, hemoglobin, ferritin, folate, or iron.

Testing becomes more relevant when sores keep recurring because studies assess vitamin B12, hemoglobin, ferritin, folate, and iron in these patients.

The takeaway is simple: vitamin C matters, but it is not the only answer. Current evidence points more strongly toward an association with vitamin B12 deficiency and low iron stores.