Canker Sores, Explained by the Science
Not home remedies. Not medical disclaimers. Mechanisms, evidence levels, and honest answers — written by someone who's read every study so you don't have to.
Every claim is sourced. Every treatment is evidence-rated.
Core Guides
The five pages every canker sore sufferer should read.
What Are Canker Sores? The Complete Guide to Aphthous Ulcers
Canker sores (aphthous ulcers) are painful oral lesions affecting 20% of the population. Here's the actual science on what they are, their three types, and what makes them distinct from cold sores.
Read guide →What Causes Canker Sores? — Mechanisms, Not Just Triggers
Canker sores are immune-mediated, not viral. Here's the actual mechanism — why immune dysregulation, nutritional deficits, SLS, stress, and genetics all converge to destroy the oral epithelium.
Read guide →Best Supplements for Canker Sore Prevention — Evidence-Graded Review
L-lysine, B12, zinc, iron, folate — which supplements actually reduce canker sore frequency? We grade the evidence for each and recommend specific products.
Read guide →Natural Remedies and Home Remedies for Canker Sores — Do They Actually Work?
Salt water, Manuka honey, baking soda, ACV, aloe — every popular natural canker sore remedy graded by what the evidence actually shows. Some work. Most don't. A few are actively harmful.
Read guide →How to Get Rid of a Canker Sore Fast — Evidence-Ranked Treatments
OTC and prescription treatments ranked by what actually speeds healing versus what just numbs pain. Steroid gels, cauterization, laser — and what to do right now if you have one.
Read guide →Canker Sore vs. Cold Sore — How to Tell Them Apart (And Why It Matters)
Canker sores and cold sores are completely different conditions — one is immune-mediated and non-contagious, the other is a contagious herpes virus. Getting this wrong means treating with the wrong drugs. Here's how to tell them apart definitively.
Read guide →Get the Treatments Guide
Free 2-page PDF: every canker sore treatment grouped by how it works and rated by the actual evidence — what speeds healing, what only numbs pain, and what's a waste of time.
Recent Articles
All articles →Did Debacterol Make My Canker Sore Worse? What's Normal and What Isn't
Debacterol usually stops canker sore pain within minutes — but sometimes the sore looks bigger, hurts again two days later, or a new raw patch appears next to it. Here's what's expected after chemical cauterization, the five real reasons it disappoints, and the signs that mean you should call the dentist.
Read →Fluoride Rinse and Canker Sores — Is It the Fluoride or Something Else?
There's no good evidence that fluoride itself causes or heals canker sores. When a fluoride rinse stings or seems to set off outbreaks, the usual suspects are the other ingredients — alcohol, detergents, flavorings, antiseptics, or an acidic formula. Here's how to tell, and how to pick a rinse if you need fluoride.
Read →Sleep and Canker Sores — Does Poor Sleep Trigger Outbreaks?
Short sleep, late bedtimes, and insomnia are consistently associated with more canker sores — in student surveys, an 11,000-person prospective cohort, and a genetic study designed to test causation. The evidence is observational, but it points one way. Here's what the studies found, the likely mechanisms, and what's worth changing.
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