At-Home Tooth Whitening Guide: How to Choose a Product and When Not to Use One

At-home whitening is a method of lightening tooth color by applying or attaching a quasi-drug whitening product yourself at home. Because low-concentration products with 3% hydrogen peroxide or less are used, following the labeled directions and period of use matters above all. If you have cavities, gum disease or sores in the mouth, it is better to see a dentist before using the product.

Published 2026-11-08 · Updated 2026-11-08 · DentalStatics editorial team

Key facts

Quasi-drug standard	Hydrogen peroxide content of 3% or less (source: Ministry of Food and Drug Safety (MFDS, 식품의약품안전처))
What to check when buying	Quasi-drug approval mark; approval can be looked up on the Drug Safety Portal (의약품안전나라) (source: Ministry of Food and Drug Safety (MFDS))
People who should avoid use	Hydrogen peroxide hypersensitivity, orthodontic treatment, children and adolescents, pregnant or breastfeeding women (source: Ministry of Food and Drug Safety (MFDS))
Gum irritation and sensitivity	Usually recover after stopping use for 1-2 days; consult a dentist if they persist (source: Ministry of Food and Drug Safety (MFDS))
Brushing right after use	Brush with a soft toothbrush without toothpaste and rinse so no ingredient remains (source: Ministry of Food and Drug Safety (MFDS))

How do I choose an at-home whitening product?

The Ministry of Food and Drug Safety (MFDS) classifies tooth whitening products with a hydrogen peroxide content of 3% or less as quasi-drugs and those above 3% as drugs. A whitening product that consumers buy directly at a supermarket or pharmacy must be approved as a quasi-drug and be labeled as such.

Check whether the package carries the quasi-drug mark, and you can look up on the Drug Safety Portal (의약품안전나라) whether a product is approved. There have been cases of people caught selling whitening products imported through overseas direct purchase without approval, so avoid high-concentration products of unclear origin.

The main ingredient is hydrogen peroxide or carbamide peroxide. Ingredients, content, duration of each use and period of use differ by product, so choose after reading the enclosed leaflet to the end.

Who should avoid at-home whitening products?

The MFDS does not recommend whitening products for people in the following groups. If it is unclear whether you fall into one, first consult a dentist or pharmacist.

If there is infection or a sore in the mouth, or tooth damage or gum disease, the irritation can be strong. People who already had sensitive teeth are also safer having the cause checked before starting.

If you find out you are pregnant while using a whitening product, stop using it right away and tell your doctor the product and the period of use to discuss it.

People with hypersensitivity to hydrogen peroxide
People wearing orthodontic appliances
Children and adolescents
Pregnant and breastfeeding women

How is each product type used?

The MFDS gives directions by type as below. Duration and frequency differ by product, so follow the directions on the container, package or enclosed leaflet.

Leaving it on longer or applying it more often than the set method can weaken and damage the teeth. Do not extend the time on your own because results are slow.

Before starting, writing the total period of use and the daily number of uses on a calendar helps prevent overuse. For products that include a whitening device such as a tray, first check that the part touching the gums is not lifting or pressing painfully.

Gel type: wipe moisture from the tooth surface, apply a suitable amount, and rinse with water after the set time. Do not close your mouth while applying.
Strip type: attach to the teeth according to the directions, then remove and rinse with water.
Toothpaste type: put a suitable amount on the toothbrush, brush, then rinse with water.

What if my gums sting or my teeth are sensitive?

Gum irritation or sensitivity can appear during at-home whitening. The MFDS advises that these usually recover after stopping use for 1-2 days, and that if symptoms continue you should stop using the product and consult a dentist.

Gums turning red or feeling sore can be a sign that the whitening product or device does not fit well. Before using the same product again, find the cause, and if there is pain even at rest, go to a dentist right away.

Right after whitening, do not use toothpaste; brush with a soft toothbrush and rinse so no whitening agent remains in the mouth. This is so that leftover ingredients do not keep irritating the gums.

How do at-home whitening and dental clinic whitening differ?

At-home whitening is a method of using low-concentration products within the quasi-drug range yourself, while professional whitening at a dental clinic uses drug-strength agents managed by the dentist. Low-concentration products work slowly and must be used consistently, and results differ greatly with usage habits.

If the discoloration is in the tooth itself rather than a surface stain, or the front teeth have resin or prostheses, it is hard to get the desired result with at-home whitening. If there is no change after several weeks, have the dentist check the cause of discoloration rather than switching products.

If the cause is tartar and staining on the tooth surface, cleaning and polishing at the dental clinic may come before a whitening agent. Having your teeth checked once at a regular checkup before starting at-home whitening also lets you avoid irritation caused by cavities or gum disease.

Common myths and facts

Myth: The more often and longer you use it, the faster the teeth whiten.

The MFDS advises that using it longer than recommended can weaken the teeth, so the set period of use must be observed.

Myth: High-concentration whitening products bought through overseas direct purchase are more effective and fine to use.

A whitening product that consumers use directly must be an approved quasi-drug, and above 3% hydrogen peroxide it is classified as a drug.

Frequently asked questions

Is whitening toothpaste alone effective?

The toothpaste type is one of the whitening product forms the MFDS describes. However, reducing surface stain and changing the tooth's own color are different, so use it as labeled and discuss the result you expect with the dentist beforehand.

Can I drink coffee during at-home whitening?

Strongly pigmented drinks such as coffee, black tea and wine, and tobacco, can bring staining back. During the whitening period it is better to cut down on these and brush right after eating them. After drinking, rinse your mouth with water.

What if a child swallows whitening product?

The MFDS stresses that the most important thing in preventing such accidents is to keep it out of children's reach from the start. If the amount swallowed is large or there are symptoms, take the product package and go to a medical institution right away, and if you cannot judge, call 119 for help.

Will a front tooth filled with resin also whiten with at-home whitening?

Whitening agents lighten the color of natural teeth, so the color of resin or prostheses may stay as it is. That can make the color difference more noticeable, so if a front tooth has a restoration, discuss it with the dentist before starting. Another option is to redo the resin to match the lightened tooth color after whitening.

Can I use sensitivity toothpaste together with a whitening product?

Right after whitening, brushing with a soft toothbrush without toothpaste is recommended. If you have sensitivity and want to use sensitivity toothpaste too, check the order and interval with a pharmacist or dentist, and stop whitening if the sensitivity continues.

References

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