(Click here  for more coverage of preventing canker sores.)
We’ve previously reported that taking supplementary lysine can significantly reduce the frequency and severity of canker sores, medically referred to as recurrent aphthous stomatitis (RAS). Up to 25% of the general population suffers from these oral lesions, and they can be extremely painful, take weeks to heal, and occur many times per year. So it would be really nice to have some options to help alleviate problems with canker stores.
Happily, vitamin B12 has been found to be yet another option for preventing canker sores. A recent study  was published in the January 2009 issue of the The Journal of the American Board of Family Medicine  that covered a small double-blind placebo-controlled trail following 58 patients suffering from RAS for a period of 6 months. 31 participants received 1000mcg (1mg) of vitamin B12  via sublingual lozenges (mouth-dissolving tablets used under the tongue), and 27 participants received placebos.
The study found that usage of vitamin B12 in this manner significantly reduced the frequency and severity of canker sores. In the last month of the 6 month study, 74.1% of the group using the vitamin B12 supplements had no canker stores versus only 32.0% in the control group receiving the placebo. The number of RAS outbreaks per month was reduced by about 77% by the use of vitamin B12.
Of particular interest, it appeared to take about 4 months for the effects of the vitamin B12 supplements to clearly differentiate the results in the two groups. It is theorized that the relatively low dosage of vitamin B12, at 1000mcg per day, took about four months to accumulate enough to have significant effect. Previous observations by the doctors conducting the study were that injection vitamin B12 at higher doses achieved a more rapid response. Vitamin B12 has very low risk of toxicity, so dosages much higher than 1000mcg per day present little risk. For instance, sublingual tablets with 5000mcg are readily available without prescription.
Some questions that remain about this study’s conclusions. For one, it is not clear if forms of vitamin B12 other than sublingual tablets would have similar effects. Regular vitamin B12 tablets that can be swallowed are very inexpensive, sublingual tablets are somewhat more expensive but can be directly absorbed into the bloodstream.
Secondly, the study does not state which form of vitamin B12 was used. Most inexpensive B12 supplements use the cyanocobalamin  form of B12 that can be converted by most human bodies into the biologically active form known as methylcobalamin . However, some people, especially the elderly and those with digestive problems, may have trouble absorbing the cyanocobalamin form and would benefit from the more expensive methylcobalamin form available in such dietary supplements as those shown to the left of this paragraph. Also, doctors have the option of prescribing Metanx  which is a swallowed tablet containing 2000mcg of methlycobalamin along with metabolically active forms of folate and vitamin B6.
If the inexpensive “swallowed tablets” form of B12 as cyanocobalamin work as effectively as the sublingual tablets did, the treatment could cost less than US$0.04 (4 cents) per day. For instance, two bottles of Puritan’s Pride Vitamin B12 (cyanocobalamin) having 250 tablets with 1500mcg of B12 per tablet  cost about US$23.99 as of this writing on the latest “buy 1 get 1 free” sale or US$47.98 for five bottles on “buy 2 get 3 free” sale. That works out to between US$0.038 (3.8 cents) to $0.048 (4.8 cents) per day or about US$14 to $17 per year.
The sublingual form at higher dosages would likely achieve a faster effect, but the cost will be somewhat higher. For instance, five bottles of Puritan’s Pride Vitamin B12 (cyanocobalamin) containing 100 lozenges each with 2500mcg of B12  would cost US$28.78. That works out to a daily treatment cost of US $0.058 (5.8 cents) per day or about US$21 per year.
If you’d really like to ramp up your B12 levels quickly and keep them high, even higher dosages are available. The 5000mcg sublingual lozenges  cost US $33.98 for 300 lozenges, or about US $0.113 (11.3 cents) per day. That’s about $41 per year, not a lot of money. When compared to the pain and inconvenience of canker sores and the cost of oral analgesic creams you may be using, it is likely to be very worthwhile.
If you combine one of these products or similar vitamin B12 supplements with L-lysine supplements, we suspect you’ll get a better overall result. L-lysine is inexpensive at about US$23.98 for five bottles on the “buy 2 get 3 free” sale of Puritan’s Pride 250 tablets of 500mg lysine  per bottle. At a typical dosage of 1500mg per day of lysine, that works out to about US$0.058 (5.8 cents) per day or $21 per year.
Vitamin B12 Overdose 
These statements have not been evaluated by the Food and Drug Administration. The products mentioned in this post are not intended to diagnose, treat, cure or prevent any disease.