The toothpastes worth avoiding fall into two categories: those with ingredients that can irritate your mouth or disrupt your body, and those missing the one ingredient proven to prevent cavities. Most mainstream toothpastes are safe, but certain formulas contain harsh abrasives, foaming agents, or flavorings that cause real problems for a significant number of people.
Highly Abrasive Whitening Toothpastes
Every toothpaste is rated on something called the Relative Dentin Abrasivity (RDA) scale, which measures how aggressively it scrubs your teeth. An RDA under 40 is considered low abrasion, 40 to 80 is moderate, and anything above 80 is classified as highly abrasive. The problem is that most brands don’t print their RDA value on the box, so you’re left guessing.
Whitening toothpastes tend to sit at the top of that scale. In lab testing, products like Colgate Optic White produced the most enamel surface change among the toothpastes evaluated. Signal White System, Biorepair, and Colgate Total Original all scored above 80, putting them in the “highly abrasive” category. If you use a high-RDA toothpaste twice a day for years, you’re gradually wearing down your enamel, which doesn’t grow back. This is especially risky if you already have receding gums or exposed root surfaces, since dentin (the layer beneath enamel) wears away faster.
Charcoal toothpastes get a lot of suspicion, and the concern isn’t unfounded. While one lab study simulating 18 months of brushing found no significant difference in enamel roughness between charcoal and regular toothpastes, other research has shown that long-term use combined with heavy brushing pressure can cause enamel wear. The bigger issue with charcoal toothpastes is that many skip fluoride entirely, which leads to the next problem.
Fluoride-Free Toothpaste
Fluoride-free toothpaste is one of the most popular “natural” trends in oral care, and it’s the single easiest way to increase your cavity risk. A large Cochrane review, the gold standard of medical evidence, found that standard fluoride toothpaste (1,000 to 1,500 ppm) consistently reduces cavities compared to fluoride-free paste across every age group studied.
In children’s baby teeth, kids using fluoride-free toothpaste developed an average of 1.86 more decayed tooth surfaces than those using fluoride toothpaste. In older children and teens with permanent teeth, fluoride toothpaste reduced cavity development by a meaningful margin across 55 separate studies. In adults, fluoride users had roughly half a decayed surface fewer over the study period, which adds up over a lifetime of brushing. The evidence is high-certainty for children and moderate-certainty for adults.
Brands marketed as “natural,” “clean,” or “toxin-free” often drop fluoride as their main selling point. Hydroxyapatite toothpaste is gaining attention as an alternative, but it doesn’t yet have the same volume of long-term evidence behind it. If you’re choosing a toothpaste and cavity prevention matters to you, fluoride should be in it.
Toothpastes With SLS if You Get Canker Sores
Sodium lauryl sulfate (SLS) is the foaming agent in most toothpastes. It’s what makes that lather you feel while brushing. For most people it’s harmless, but if you’re prone to canker sores, SLS may be making them worse. The compound strips away the protective mucus layer lining your mouth, leaving the tissue underneath exposed and more vulnerable to ulceration.
If you get recurring canker sores, switching to an SLS-free toothpaste is one of the simplest things to try. Brands like Sensodyne, Biotene, and Verve explicitly skip SLS. Many people who make the switch notice fewer outbreaks within a few weeks, though it won’t eliminate canker sores caused by other triggers like stress or nutritional deficiencies.
Cinnamon-Flavored Formulas
Cinnamon flavoring in toothpaste uses cinnamic aldehyde, a compound derived from cinnamon cassia oil. It’s a known topical sensitizer, meaning it can trigger allergic contact reactions in the mouth. Symptoms include acute stomatitis (painful inflammation of the mouth lining), redness, swelling, and sometimes a rash spreading to the lips and surrounding skin.
Cinnamon allergy is not rare, and the tricky part is that cinnamic aldehyde shows up in many products beyond toothpaste, so people who react to it may not immediately connect their symptoms to their oral care. If you’ve noticed persistent mouth irritation, peeling tissue, or a burning sensation that doesn’t match other causes, your toothpaste’s flavoring is worth investigating. Mint-flavored alternatives are far less likely to cause contact reactions.
Toothpastes Still Containing Triclosan
Triclosan is an antibacterial chemical that was once the star ingredient in Colgate Total. In 2016, the FDA banned triclosan from consumer antiseptic wash products after manufacturers failed to prove it was both safe and more effective than regular soap. Toothpaste wasn’t included in that ban because Colgate did submit data showing triclosan helped prevent gingivitis, but the company has since reformulated, and triclosan is no longer in most products on U.S. shelves.
The concern with triclosan centers on its potential to interfere with hormone function and contribute to antibiotic resistance. While you’re unlikely to find it in major American brands today, it still appears in some imported or off-brand toothpastes. Check the ingredient list if you’re buying unfamiliar brands, particularly from international sellers.
Microplastic-Containing Toothpastes
Some toothpastes contain tiny polyethylene microbeads, originally added for a scrubbing texture. These plastic particles can become trapped under the gumline, where they aggravate gum inflammation over time. You also swallow small amounts of toothpaste with every brushing session, and ingesting microplastics daily is a growing health concern.
A systematic review of toothpastes from multiple countries found that microplastic content varies widely by region. Products from Malaysia, Turkey, and India contained polyethylene, polypropylene, polyvinyl chloride, or polyamide particles, while those from China, Vietnam, Myanmar, and the UAE tested clean. In the U.S., most major brands phased out microbeads after the Microbead-Free Waters Act of 2015, but they can still appear in some imported products. Look for “polyethylene” in the ingredients list to spot them.
How to Pick a Safe Toothpaste
The simplest shortcut is the ADA Seal of Acceptance. To earn it, a toothpaste must submit clinical or laboratory data proving both safety and effectiveness. The seal is renewed every five years, and any formula change during that period requires the company to resubmit safety data before selling the product with the seal. It’s not a perfect guarantee, but it filters out the worst offenders.
Beyond the seal, a good toothpaste for most people contains fluoride at 1,000 ppm or higher, has a low to moderate RDA (under 80), skips SLS if you’re canker-sore prone, and avoids cinnamon flavoring if you have sensitive oral tissue. You don’t need activated charcoal, microbeads, or antibacterial additives. A basic fluoride toothpaste with the ADA Seal does everything the expensive, heavily marketed alternatives claim to do, usually for a fraction of the price.