Mouth ulcers, otherwise known as canker sores or aphthous ulcers, are the exact opposite of fun. Many of us will experience them at some point in our lives — the telltale white sore patch of skin, technically called a "lesion," on our gums or the sensitive inner lining of our mouths, that dooms us to a period of sensitivity and aching before it goes away. While canker sores are super common, they're also medically complex things — and we're still figuring out why they exist and how to make them go away quickly.
There isn't one "cause" of canker sores. The Mayo Clinic identifies several, including food sensitivities, mouth injuries (you'll likely experience them if you have braces, for example), bacteria, highly spicy or salty food, and (classic!) stress. Interestingly, they're also related to menstruation in women — the luteal phase, the stage of the menstrual cycle where there's a peak in progesterone, also sees an increase in mouth issues and ulcers in women because progesterone alters hormonal balance.
This information is helpful for preventing them, but is there anything you can do to get them gone for good? Science has a lot of answers, and new ones are appearing regularly. Canker sores are known as "self-limiting", in that they often go away on their own — though a particular type, herpetiform canker sores, forms a "cluster" of many tiny ulcers that get worse before they get better. Typically people with severe mouth ulcers are given products that contain mild antiseptics and pain relief, to help prevent further infection and stop the ulcers getting irritated.
But one study found that a pretty common supplement could help ward off future outbreaks if you're prone to the pesky sores: a nightly dose of vitamin B12. The study, which was published in the Journal of the American Board of Family Medicine in 2009, gave nightly doses of B12 to people diagnosed with recurrent aphthous stomatitis (RAS), aka commonly get canker sores. It then found that B12 treatment caused big reductions in the severity of outbreaks, how many ulcers people had, and whether they got any at all.
There are limitations to this, though. The B12 dosage was maintained over six months, which is a long time, so this is hardly a quick fix. The dose used by the scientists was 1mg a day, and the National Institutes Of Health report that it's not considered possible to "overdose" on B12, but it's still a good idea to talk to your doctor before using daily B12 doses to treat your canker sores, particularly if they're not recurrent ones. If you'd like a quicker fix, research has also shown that gels with propolis, the resin produced by bees to construct hives, are highly effective for helping the healing process.
In the future, though, things may be more high-tech; a study of mouth ulcers in patients undergoing chemotherapy in 2013 found that preventing further ulcers with low-level laser therapy is actually pretty effective. Low-level laser therapy is used a lot to help tissue healing, and it's not quite clear how effective this would be in people who aren't currently undergoing chemo, but it's still an interesting perspective. Maybe in a few decades your doctor will point a handheld laser at your mouth, rather than handing over yet another gel and encouraging you to stay away from spicy food.