Do Teeth Whitening Strips Work?

Best Teeth Whitenning

Thinking of buying teeth whitening strips but not sure if they'll work? No doubt, teeth whitening strips are one of the cheapest products available to brighten your smile. However, they may not be ideal for every dental case.

It’s best that you understand how teeth whitening strips work (and in what situations) before making a purchase. The truth could save you time, money, and, most of all, disappointment from an unchanged smile.

In this article, you’ll learn everything there is to know about teeth whitening strips: how they work, in which cases they give the best result, and what to expect when using them to get the whitest possible smile from your treatment.

How to Use Teeth Whitening Strips

It’s best practice to brush your teeth before using teeth whitening strips—or any form of tooth whitening treatment. Brushing will remove food debris stuck between your teeth to ensure an even application of the whitening agent over your enamel.

When it comes to promoting optimal oral hygiene, we’d like to take it a step further. We typically recommend that you have a cleaning done with your dental hygienist before beginning your whitening treatment. The ultrasonic scaling instrument used for oral cleanings will remove any plaque over your teeth. This ensures that the whitening strips will have full contact with your tooth surfaces. Otherwise, you may notice that areas with untreated plaque are much darker than the rest of your teeth.

That said, it’s safe to brush your teeth at least 30 minutes before applying whitening strips to prevent gum irritation.

How do you apply teeth whitening strips?

Every package comes with two whitening strips—one for your upper arch and another for the teeth on your lower arch. One side of the strip is glossy, while the other has a gel coating that contains the whitening agent. You’ll notice there’s also a liner over the gel to prevent smudges.

Here’s how you apply the teeth whitening strips:

  1. Start by drying your teeth with a clean paper towel. The whitening gel adheres best to dry surfaces; saliva can cause the strips to slip off your teeth.
  2. Peel away the liner over the gel-coated side of the whitening strip.
  3. Place the gel-coated surface over your teeth and align the edge of the strip with your gum.
  4. Gently press on the strip to help it adhere to your teeth.
  5. Fold any overhanging ends of the strip on the inner surface of your teeth. It’s not unusual for the strip to extend past your teeth. Over-the-counter whitening products are one-size-fits-all, so to speak, and some people have smaller jaws than others.

Leave the strips on for as long as the packaging indicates. Some whitening products may ask you to apply them for as little as 5 minutes, while others go up to half an hour. Brands like Crest 3DWhitestrips also include an LED Accelerator Light that you’ll need to wear during application.

Other brands may also advise you to use the whitening strips twice a day to achieve the best results. This all depends on the concentration of hydrogen peroxide used in the gel. The stronger the product, the less time needed to take full effect.

It’s important that you follow the instructions on your packaging carefully. Using whitening agents for too long can cause the enamel to become soft and prone to damage. For this reason, we recommend rinsing with tap water once you’ve removed the strips. Rinsing will help to remove any whitening gel stuck on your teeth. You can also try wiping the gel off with a clean tissue.

Do not use a toothbrush immediately after using whitening strips. The bristles of the toothbrush can damage the softened enamel and roughen the tooth surface2.

You can resume brushing your teeth with a soft-bristle toothbrush approximately half an hour after removing the strips to avoid gum irritation.

How Do Teeth Whitening Strips Work?

Teeth whitening strips use a low concentration of hydrogen peroxide to bleach the teeth. Carbamide peroxide is a much stronger form of peroxide. It is usually used for professional whitening appointments. However, some at-home whitening strips may contain low concentrations of this bleaching agent as well.

Do strips actually work to whiten teeth?

The peroxide in whitening strips works by penetrating the tooth surface to lift mild stains and discolorations. The result: a brighter, whiter smile.

Know that you may still have slightly yellow teeth after the first application. Remember, most over-the-counter whitening products use less than 6% peroxide in their bleaching gels, so you’ll need more than one session to achieve full results. Even Crest Whitestrips Supreme, which uses 14% hydrogen peroxide, indicates to use the strips twice daily3.

Are Teeth Whitening Strips Safe?

Teeth whitening strips are generally safe and efficient at boosting your confidence with a pearly white smile.

Wondering what other benefits there are to using teeth whitening strips?

Firstly, they’re one of the most affordable whitening products. Teeth whitening strips cost $50 (or less) per box. Compare that with professional teeth whitening treatment, which costs upwards of $650, or take-home trays in the range of $4001, and you’ve got a true bargain! Cosmetic dentistry doesn’t have to be expensive.

Teeth whitening strips are also easier to apply than other at-home bleaching packages. Gel trays, for example, pose the risk of oozing peroxide that can burn your gums, tongue, and throat. This tends to happen when people don’t follow instructions directly and insert too much gel into the trays. Luckily, whitening strips come prepared with just enough gel to coat your teeth. You won’t have to worry about excess gel dripping into the back of your mouth.

Will Whitening Strips Make My Teeth Permanently White?

Most whitening strip treatments last for 14 days (that’s when the strips in the box usually run out). However, you’ll need to retouch your whitening treatment every 6 months to maintain a bright smile. Of course, your teeth may develop stains during that time without proper oral hygiene.

Here are a few tips for keeping your teeth as white as possible in between treatments:

  • Brush your teeth after every meal to safeguard against developing stains from food and beverages with natural dyes. These include curry, turmeric, red wine, teas, and coffee.
  • Drink through a straw, especially if you’re having colas or other colored sodas that can stain your teeth.
  • Abstain from cigarette smoking as nicotine creates deep, black tooth stains.
  • Floss twice every day to keep your gums and teeth healthy.
  • Schedule regular 6-month cleanings with your dental hygienist to maintain your oral health. In some cases, your dental care provider may recommend that you see a hygienist sooner.

Should I Use Teeth Whitening Strips?

You might be wondering, “Will teeth whitening strips work for me?” If you are, then kudos to you! Too often, patients avoid talking to their dental care providers before purchasing over-the-counter whitening products. However, not all whitening products work effectively; and teeth whitening strips may not be the best option for you.

It’s important that you speak with a dentist before starting teeth whitening treatment, especially if you suffer from:

  • Tooth decay
  • Tooth sensitivity
  • Gingivitis (gum disease)
  • Thrush (an oral yeast infection)
  • Cold sores
  • Canker Sores

Bleaching agents contain potent ingredients which may irritate existing blisters or aggravate tooth pain.

In addition, teeth whitening strips (or any bleaching agent) cannot alter the color and shade of tooth restorations. This means that the peroxide will not turn a silver crown to the color of your teeth. Neither will it brighten the shade of porcelain veneers5.

You should also note that teeth whitening strips are only effective on surface stains, or extrinsic stains. They can also brighten mild tooth discolorations.

Large brown or black stains need more invasive bleaching treatment with your hygienist (no need to worry: whitening treatments don’t usually involve any sedation dentistry). These procedures may involve whitening agents with higher concentrations of peroxide to penetrate deep into the enamels. Dental hygienists - and some dentists - are trained to use these products to ensure your safety.

Moreover, teeth whitening products cannot whiten teeth that have turned black due to a traumatic injury. Say you fell and knocked your tooth, then it turned black. The discoloration here isn’t a stain. Instead, it’s the result of damage to the tooth’s blood supply. A lack of nutrients causes the tooth to “die” and darken6.

What are the Side Effects of Teeth Whitening Strips?

Tooth whitening strips have 3 main side effects: gum irritation, tooth sensitivity, and demineralization5.

Gum irritation may occur if you use a hard-bristle toothbrush which causes micro blisters on your gums. When the peroxide comes in contact with those blisters, it stings—similar to when you pour disinfectant over a wound! The good news is that the irritation is usually temporary.

Tooth sensitivity occurs when the bleach in whitening strips penetrates the enamel and reaches the dentin. The dentin is the layer closest to the nerves in the pulp of your teeth.

Mild sensitivity is expected with any whitening treatment. The discomfort will usually subside within 24 to 48 hours. Your dentist may prescribe desensitizing toothpaste to reduce the sensation4.

However, you should discontinue the use of any product if you begin to experience increased tooth sensitivity or extreme pain.

Bleaching agents may enter the dentin if you’ve used your whitening strips for too long. It could also happen if you’re using a whitening agent with dangerously high concentrations of peroxide. The latter is not as uncommon as you think. Many online manufacturers sell teeth whitening products with peroxide concentrations that surpass the American Dental Association’s guidelines. In severe cases, patients have had to receive crowns to protect their teeth from heat, cold temperatures, and other common triggers for their ongoing sensitivity.

For your safety, our advice is to only purchase whitening products from trusted brick-and-mortar pharmacies.

Demineralization refers to when the enamel loses ions, like calcium, from its crystal structure. Wearing whitening strips for extended periods may give leeway for the bleach to begin eroding the tooth and causing permanent damage.

These side effects may sound concerning. However, the odds of experiencing any of these are low, so long as you follow the directives of your care provider and the instructions on your whitening package.

Are Teeth Whitening Strips Worth It?

Teeth whitening strips are a convenient solution to achieving a whiter smile. However, you should speak with a trained professional at your regular dental office to ensure that bleaching is safe for you.

Once you’ve got the all-clear from your dentist, be sure to purchase a teeth whitening kit from a reputable oral hygiene brand. Your dentist may be able to recommend a brand that they trust.

Follow the manufacturer’s directives to receive the best result from your whitener strips. This will reduce your likelihood of experiencing gum irritation, tooth sensitivity, or damage to your teeth.

Enjoy your new, pearly white smile!


  1. Addleson, L. (Ed.). (2019, April 18). Professional teeth whitening: Dentist-administered whitening treatments. Your Dentistry Guide. Retrieved August 18, 2022, from,is%20not%20a%20permanent%20solution
  2. Carey, C. M. (2014). Tooth whitening: What we now know. Journal of Evidence Based Dental Practice, 14, 70–76.
  3. Sagel, P. A., & Landrigan, W. F. (2004). A new approach to strip-based tooth whitening: 14% hydrogen peroxide delivered via controlled low dose. Compendium of continuing education in dentistry (Jamesburg, N.J. : 1995), 25(8 Suppl 2), 9–13.
  4. Sensitive teeth. Mouth Healthy TM. (n.d.). Retrieved August 18, 2022, from
  5. Whitening. American Dental Association. (n.d.). Retrieved August 18, 2022, from
  6. Whitening: 5 things to know about getting a brighter smile. Mouth Healthy TM. (n.d.). Retrieved August 18, 2022, from