Teeth whitening is sold in three very different places: a dentist's chair, a salon or mall kiosk, and your own bathroom. The chemistry is mostly the same. The strength of the product, who checks your mouth first, and who is legally allowed to apply it are not.
This guide covers what the American Dental Association (ADA) says about each route, what the FDA has said about whitening products, and how Texas and Arizona law treats whitening done by someone who isn't a dentist.
How whitening works, and what it can't do
The ADA's whitening topic page sorts tooth discoloration into two kinds:
•Extrinsic stains sit on the enamel surface. Coffee, tea, red wine, cola, and tobacco are common causes. Brushing with a whitening toothpaste or a professional cleaning can reduce many of them.
•Intrinsic stains are inside the tooth, in the enamel or the dentin underneath. Aging, fluorosis, and certain antibiotics taken in childhood (tetracycline, for example) are among the causes. Reducing these takes a chemical reaction.
That chemical reaction comes from peroxide. The ADA says the most common bleaching ingredients are carbamide peroxide and hydrogen peroxide. Carbamide peroxide releases about one-third of its content as hydrogen peroxide, and hydrogen peroxide diffuses through enamel easily enough to reach the pulp within 15 minutes of exposure. That's part of why sensitivity is so common.
Two limits are worth knowing before you spend anything:
•Only natural teeth whiten. The ADA notes that tooth-colored restorations, including crowns, won't change color. If you have visible dental work on your front teeth, whitening the teeth around it can leave a mismatch.
•The type of stain matters. According to the ADA, brown stains from fluorosis or tetracycline may respond better than white spots, and tetracycline staining can take an average of three to four months of nightly treatment.
The three routes
In-office whitening at the dentist
In-office treatment usually means a peroxide gel applied by the dentist, sometimes with a light meant to speed the process. The ADA also describes "power bleaching," which uses concentrated hydrogen peroxide solutions for up to 30 minutes.
The ADA describes a clinical exam before bleaching, with X-rays and other tests as appropriate, to work out what's causing the discoloration. The health history covers allergies, which can include ingredients in bleaching materials, and any history of tooth sensitivity. Because in-office gels are strong, the dentist protects the gums with a barrier. One researcher the ADA cites suggests avoiding local anesthesia during in-office bleaching so patients can feel any burning that signals gel leaking past the barrier.
Take-home trays from the dentist
The second route is a custom tray made in the dental office and filled with gel at home. The trays are built to fit closely and keep gel off the gums. The ADA says these systems typically use 10% to 38% carbamide peroxide. One systematic review it cites found daily wear times from 2 to 10 hours over 6 to 28 days, depending on the product.
Over-the-counter products
Drugstore strips, paint-on gels, trays, and toothpastes use the same peroxides at lower concentrations, according to the ADA. Whitening toothpastes rely mainly on abrasives to remove surface stains, though some contain small amounts of peroxide.
The trade-off is time. The ADA cites a study in which an over-the-counter product took 16 days to reach the whitening level of a 7-day take-home tray system and a 1-day in-office procedure.
If you buy over the counter, the ADA Seal of Acceptance is a voluntary program. The ADA's whitening page says products carrying the Seal include toothpastes and whitening strips, and that the company behind each one has shown the product meets the Seal program's safety and effectiveness requirements when used as directed. Products dentists supply or apply are "professional products" and aren't eligible for the Seal, so a missing Seal on those doesn't mean anything.
What about charcoal and other DIY methods?
The ADA says there's insufficient evidence that charcoal-based products whiten teeth safely and effectively. It describes one study in which a charcoal-and-salt mixture was abrasive and ineffective and left deep abrasion cavities on the front teeth. Another study it cites found no measurable whitening from a strawberry-and-baking-soda mix. The ADA also notes no documented whitening from oil pulling.
Side effects
The ADA lists two common adverse effects:
•Tooth sensitivity. It can affect up to two-thirds of users early in treatment. It's usually mild and temporary. With strips or trays, it may start two to three days into treatment and usually resolves by the fourth day after you finish. Higher concentrations tend to cause more of it.
•Gum irritation. This usually comes from poorly fitting trays or gel that gets past a barrier. It's typically temporary too.
Three less obvious points from the same page:
•Enamel surface. Some research suggests bleaching may change the surface roughness of enamel, which may also weaken how well bonding materials stick to the tooth afterward. Mention any recent or planned bonding to your dentist.
•Children. The American Academy of Pediatric Dentistry discourages full-arch cosmetic bleaching in children who still have baby teeth or a mix of baby and adult teeth.
•Cancer concerns. A 2022 systematic review the ADA cites concluded that hydrogen peroxide whitening products do not appear to have carcinogenic effects on the lining of the mouth.
What the FDA has said about whitening products
In 2009, the ADA filed a citizen petition asking the FDA to "review and establish an appropriate regulatory classification" for peroxide whiteners. On April 22, 2014, the FDA denied the petition (Docket No. FDA-2009-P-0566). The letter says three things worth knowing:
•Most whiteners are cosmetics. The FDA wrote that "most peroxide-containing tooth whiteners would meet the definition of a cosmetic." Cosmetics can be sold without FDA preapproval.
•Whether they're also drugs is unresolved. The FDA said there was "insufficient data to determine whether, as a group," these products meet the definition of a drug, and that it would need to look at specific products case by case.
•No concentration limit. The FDA said whiteners "may be suitable for use without the supervision of a licensed practitioner and used safely," but that it didn't have enough data to draw a definitive conclusion about the risks or to say what concentration limit would be safe for consumer use.
As of November 2026, the FDA's 2014 letter is the latest document in that petition's public docket. In practice, labels such as "dentist-strength" or "professional-grade" on a consumer product aren't FDA designations.
Who can legally whiten your teeth
This is where the setting matters most, and where the answer depends on your state.
The ADA's position isn't law
The ADA's 2008 policy on whitening by non-dentists, published on the same ADA page, urges state dental societies to support laws or rules treating the application of "any intra-oral chemical for the sole purpose of whitening/bleaching of the teeth," other than self-application or application by a parent or guardian, as the practice of dentistry. That's a professional association's position. Whether it's the law depends on each state's dental practice act.
The Supreme Court case about whitening
Whitening by non-dentists reached the U.S. Supreme Court in North Carolina State Board of Dental Examiners v. FTC, decided February 25, 2015. The Court's syllabus notes that North Carolina's Dental Practice Act "does not specify that teeth whitening is 'the practice of dentistry,'" yet the state board, after complaints from dentists, issued at least 47 official cease-and-desist letters to non-dentist whitening providers and product manufacturers.
The Court held that a board controlled by active market participants can claim state-action immunity from antitrust law only if the state actively supervises it, and North Carolina's board wasn't actively supervised. The case was about antitrust and how boards make decisions. It didn't decide whether whitening is safe or whether it's dentistry.
Texas
The Texas Dental Practice Act doesn't mention whitening by name. Its definition of practicing dentistry, in Texas Occupations Code § 251.003, includes a person who "performs or offers to perform by any means the ... removal of stains, concretions, or deposits from teeth in the human mouth."
Texas lawmakers have tried to name whitening outright. House Bill 3220 in 2011 and House Bill 502 in 2013 would have added "a teeth whitening treatment" to the definition of practicing dentistry, while excluding products sold over the counter to consumers. Neither became law. HB 3220 was referred to committee and went no further. HB 502 passed the Texas House and was last referred to a Senate committee on April 29, 2013.
So as of November 2026, Texas has no whitening-specific statute, and how the stain-removal language applies to a non-dentist whitening business is for the Texas State Board of Dental Examiners and the courts to decide.
Arizona
Arizona's definition is more direct. Arizona Revised Statutes § 32-1202 defines the practice of dentistry to include "removing stains, discolorations and concretions."
A 2018 bill, HB 2402, would have let businesses not registered with the dental board offer "teeth-whitening services" with nonprescription products. They would have had to post a sign saying the service is unregulated, serve only customers 18 and older, and throw away trays and other items after each use. The bill was held in committee and didn't become law. As of November 2026, the statute's definition is unchanged, and the Arizona State Board of Dental Examiners interprets and enforces it.
What this means for you
Both states' statutes put stain removal inside the definition of dentistry. If a salon, spa, or kiosk offers whitening, ask:
•Who will apply the product, and what license do they hold?
•Will you apply it yourself, with staff only supplying the product?
•What product is it, and what peroxide concentration?
If the answer is "a technician," with no dental license involved, you're in the area these statutes and the ADA's policy address. To check a dental license, use your state dental board's online lookup. If a med spa offers whitening, our guide to checking a provider's credentials walks through license lookups for the rest of the staff.
Questions to settle before you whiten
•What's causing the discoloration? Surface stains, intrinsic stains, and discoloration from decay or old fillings call for different approaches. That's the main reason the ADA describes an exam before bleaching.
•Do you have crowns or bonding on visible teeth? They won't whiten, and you may want to plan around them.
•Have you had sensitivity before? Tell your dentist. The ADA notes higher concentrations and longer contact times tend to cause more of it.
•Is the person under 18, or does the child still have baby teeth? The pediatric dentistry academy's caution applies.
•For over-the-counter products, does it carry the ADA Seal? It's voluntary, but it means the maker has shown the product meets the program's safety and effectiveness requirements when used as directed.
•Who is applying the gel, and are they licensed? In Texas and Arizona, the answer matters legally as well as clinically.
Whitening is cosmetic, but it's still a chemical applied to living teeth. The exam, the product, and the person applying it all deserve the same scrutiny you'd give any other treatment.
This article is educational and does not constitute medical advice. Always consult a licensed medical professional for personalized recommendations.
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