Crest Whitestrips: Do They Work? And Are They Safe?

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Hi, I’m Dr. B, practicing functional dentist for 35 years. I graduated from the Dugoni School of Dentistry in San Francisco, CA in 1987 and am a member of the American Academy of Dental Sleep Medicine (AADSM), Academy of General Dentistry (Chicago, IL), American Academy for Oral Systemic Health (AAOSH), and Dental Board of California. I'm on a mission to empower people everywhere with the same evidence-based, easy-to-understand dental health advice that my patients get. Learn more about Dr. B

Crest Whitestrips seem like the perfect solution to a smile that’s less white than you’d like—they’re convenient, affordable, and more popular than ever.

But the question is: Do Crest whitestrips really work? And are they safe?

In truth, teeth whitening strips do work to make teeth look whiter and brighter. But before you try them, I want you to understand some of the risks of this teeth whitening method.

But before I explain how Crest whitening strips (by P&G Brands) and similar brands work (and how to use them safely), I want to explain why teeth get stained and yellowed in the first place.

Later, I’ll also share some safer and more effective ways to brighten your smile and provide advice on how to prevent discoloration.

Let’s get started!

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How do teeth get stained?

There are two parts of your teeth—the inner dentin and outer enamel. Here’s a look at how the dentin and enamel can become stained or discolored.

Causes of Dentin Discoloration

Age: As we age, our dentin naturally becomes more yellow. Even with the whitest possible enamel, yellow dentin will cause teeth to look yellow because its color is refracted through the outer enamel like a prism.

Grinding and dental trauma: Any trauma to the tooth—whether caused by grinding (also known as bruxism), a fall, or direct force—causes the tooth to age prematurely. And, as mentioned above, aging dentin is yellow dentin.

Poor nutrition or hydration: Missing out on important nutrients? Your teeth will eventually show it as lack of proper nutrition also causes dentin to age sooner than it should. This can also happen when you don’t drink enough water, as your mouth (and entire body) needs to stay hydrated to stay young.

Think of it this way—your teeth can get dehydrated, just like the rest of your living tissue. And the fix is pretty simple: stay hydrated and nourished.

Other causes: There are other rare reasons your dentin can become yellow, like:

  • Taking the antibiotic tetracycline before 10 years old
  • A genetic disorder called amelogenesis imperfecta
  • Amalgam/mercury fillings
  • Genetics (some people are just more likely to have yellower teeth)

Causes of Enamel Staining

Highly pigmented foods and beverages: Certain foods and drinks like wine, kombucha, and coffee can cause staining of the teeth’s outer enamel. Rinsing your mouth with water during and after can help minimize staining.

Dental fluorosis: Drinking fluoridated water as a child can cause dental fluorosis, which can cause white or brown discolorations on teeth. Unfortunately, fluorosis can’t be reversed (and it’s a sign of more serious problems).

Tobacco: Similarly to pigmented beverages, the tobacco in cigarettes, chew, and cigars will yellow the enamel of your teeth.

How Crest White Strips Work + How to Use Them

Crest Whitestrips and similar products work by coating the teeth with a gel that contains hydrogen peroxide or carbamide peroxide. This gel is pressed against the teeth long enough for its ingredients to penetrate the teeth and create a whitening effect.

Whitening strips are small pieces of a flexible plastic called polyethylene, a common plastic that is safe for one-time use. Once coated with a whitening gel, each strip is molded around the teeth—one strip for the top and one strip for the bottom.

While the plastic used by white strips is seemingly non-toxic, the adhesive chemicals may be problematic for some.

Crest Whitestrips use polyvinylpyrrolidone (PVP) to bind strips to teeth. The Environmental Working Group (EWG) rates this adhesive as safe, meaning it doesn’t bioaccumulate or disrupt hormones, like many household chemicals. (1) The strips also contain carbomer, another fairly safe chemical, to increase the adhesion of the gel. (2)

Though they are considered safe, these adhesives can irritate the gums and unnecessarily damage enamel, especially when overused.

And regarding hydrogen peroxide, the whitening agent used in these strips, there is no question about its potential danger.

It is true that hydrogen peroxide does whiten teeth. This chemical can pass into the enamel of the tooth and help reverse some discoloration of both teeth and dentin by breaking down the organic molecules inside that make teeth look yellow.

But the European Union (EU) and Canada’s governmental body classify hydrogen peroxide as toxic or harmful when used in the mouth, and I totally agree with that assessment. (3)

It can destroy the oral microbiome, killing off the beneficial bacteria that prevent cavity formation, gum disease, bad breath, and other conditions.

I’m also concerned about the pH-balancing ingredient in white strips, sodium hydroxide. It’s an ingredient considered toxic when used inside the body and is a “caustic agent,” meaning it corrodes what it touches. (4)

Sodium hydroxide is also used in hair dye. Essentially, just like you can strip your hair too much from over-dyeing it, you can do the same with teeth. (Instead of brittle hair, think: sensitive teeth.)

That said, despite the risks, you may find the need to whiten your teeth. Let’s talk about how to do it effectively and safely so you minimize your risk while still getting the results you want.

How to Use Crest Whitestrips

When you open a package of whitening strips, you’ll see that there are different packets for upper and lower sets of teeth. Remove each strip from the packet and cut away any additional area that would touch your gums. Then, adhere the strips to the appropriate teeth.

Most Crest Whitestrips are designed to be worn about five minutes each day—even the Crest website suggests not using them for longer. More than five minutes increases your chance for tooth sensitivity.

For faster results, you can buy Crest 3D whitening strips, the most powerful Crest Whitestrips. These are designed to stay on the teeth for 30 minutes and whiten quickly in just one use. Some of these whitening kits come with UV lights to “speed” the process, although I’m skeptical of that part of the process offering much help.

According to Crest, you can use whitening strips up to twice every day. You should not brush your teeth before using whitening strips. Many people choose to brush afterwards, but this risks pressing down the abrasive chemicals into the enamel of your teeth.

Never wear Crest Whitestrips overnight or while sleeping/napping.

Manufacturers like Crest encourage you to use whitening strips along with Crest whitening toothpaste for a brighter smile. However, whitening toothpaste marketing is very clever—and sometimes misleading.

At best, Crest’s whitening toothpaste may help remove some surface stains (called extrinsic staining). The peroxide in Crest Whitestrips, however, will actually whiten the tooth’s color.

Crest Whitestrips Before & After

Check out the results some people have found with Crest Whitestrips:

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Problems with Crest Whitestrips

Here are some of the major problems I see with Crest Whitestrips and similar at-home whitening methods:

Gum Damage

The chemical reaction that must occur in order to make your teeth appear whiter can damage your gums. But it’s not just the whitening process that’s dangerous—both sodium hydroxide and PVP can irritate gums, particularly the former.

This is why it’s essential to make sure that whitening strips never touch your gums.

This is hard to do, but it’s possible: Cut the strips so they don’t overlap with or touch your gums, as they should touch only your teeth.

Yellow Spots

Whitening strips are one-dimensional, but teeth are three-dimensional. This creates a problem when it comes to getting the results you want because the flat strips can’t get into the in-between spaces or the curved bottoms of teeth.

Often, the center of the tooth is whitened, but the curved edges of the tooth remain yellow or gray.

The spots that weren’t whitened don’t become more yellow than before—they simply look more pronounced because the color difference is so striking. And it’s likely that your unevenly whitened teeth may be even more of a cosmetic frustration than having evenly discolored teeth.

Tooth Damage

When a dentist isn’t around to monitor a whitening treatment, I get a little nervous. It is very possible to overdo it and damage your teeth.

This is especially true with at-home whitening, because these agents work by oxidizing (whitening) the tissue in between the enamel rods within your tooth structure.

The truth is, enamel is there to protect your teeth from decay, so overuse of Crest Whitestrips and other similar products may cause unnecessary damage and make you more susceptible to cavities and sensitivity.

Increased Sensitivity or Pain

Damaging the enamel of your teeth can inadvertently expose more of the dentin, which is the living, inner layer of tooth tissue.

After using Crest Whitestrips or other at-home whitening kits, you may notice your teeth become more sensitive to hot or cold, or that you experience soreness or pain throughout your mouth when eating certain foods, especially sugary treats.

At the very least, you should visit your dentist and make sure you don’t have any cavities before using whitening strips.

Problems with the Oral Microbiome

Peroxide kills bacteria very successfully—which is exactly why you don’t want in your mouth.

You need a balance of good bacteria in your mouth in order to prevent cavities and other oral health issues, but hydrogen peroxide totally disrupts the balance of your oral microbiome and may cause more issues than the cosmetic one you’re trying to fix.

The Best Alternatives to Crest Whitestrips

As you may have guessed, I don’t personally use Crest White Strips. However, despite the risks, you may still want to use them.

There are two types of whitening—extrinsic (removing stains) and intrinsic (actually whitening enamel)—and each are achieved via different methods.

Best Extrinsic Whitening Methods

There are some great natural teeth whitening methods that can remove years of stains and external damage caused by pigmented drinks.

Before I share my favorites, though, I want to say this as an aside: Many people recommend teeth whitening at home via apple cider vinegar or strawberries. These things work because the acids they contain corrode the top layer of enamel.


Sure, you’ll see some stains go away at first, but using acidic agents like this can make your teeth age faster, which will make your dentin yellow more quickly and cause more discoloration in the long run.

In fact, I tell my patients to rinse their mouths with water after eating foods that contain vinegar, citrus, or acidic fruits such as strawberries.

1. Turmeric

My DIY Turmeric Teeth Whitening Paste uses the power of turmeric, one of the most powerful herbs on the planet, to remove stains.

Turmeric has primarily been researched because of its anti-inflammatory and disease-fighting prowess. (5, 6) But there has been some anecdotal support for its ability to remove dental stains.

To make this paste, you’ll combine turmeric with baking soda, L-arginine, and coconut oil. Not only will it help with removing stains, but it will also promote proper balance of your oral environment and help to prevent gum disease and other inflammatory concerns.

2. Activated Charcoal

Activated charcoal is another known stain-removing ingredient. Known as a detoxifier, activated charcoal binds to toxins and chemicals and serves as a vehicle to remove them from the body. In a similar fashion, it can bind to molecules on the teeth that cause discoloration from eating pigmented foods and drinks.

My DIY Activated Charcoal Toothpaste Recipe will allow you to replace your Crest Whitestrips with a much safer alternative. You simply let it sit for 5-10 minutes on the teeth to bind to stains before rinsing.

Some people get activated charcoal for the teeth from capsules, but the particle size can be too large and may scratch your teeth from being too abrasive. If you choose to do this, I recommend smearing the paste you make onto your teeth, rather than brushing it in.

When looking for an activated charcoal toothpaste, make sure the consistency is creamy rather than gritty. Here are some of my favorites:

Best for Non-Toxic Stain Removal
Image alt All-natural ingredients with no icky additives—this stain-removing toothpaste ticks all my boxes.

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Best for Stain Removal + Biome Management
Image alt Hyperbiotics includes some great oral probiotics in their charcoal paste. If you struggle with a dry mouth, bad breath, or cavities, this is the best option for you.

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Best for DIY toothpaste
Image alt This is the powder I’d recommend for any DIY charcoal toothpaste, as the particles are small enough not to scratch the surface of your teeth.

Buy Now

3. Stain-Removing Toothpaste

For stain removal, I believe the best whitening toothpaste is Jason’s Powersmile Toothpaste. But even though I recommend this brand, you shouldn’t use it regularly, as the ingredients are more abrasive than I typically like.

Best For Short-Term Stain Removal
Image alt For 2-3 weeks, try this more abrasive, non-toxic toothpaste to get rid of surface stains.

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2-3 weeks is all you should need to get rid of some of the more obvious stains—anything longer than that may start to damage the enamel.

Many people flock to whitening toothpastes to try to achieve a whiter smile. As I’ve mentioned, you can remove some extrinsic stains this way, but you won’t be able to actually change the color of your enamel or dentin with toothpaste.

4. An Electric Toothbrush

One of the best ways to eliminate stains and brighten teeth is to use a good electric toothbrush. For this purpose, I recommend the new Goby electric toothbrush. It is modeled after the Oral-B design and is great for removing stains from teeth.

The Goby can be purchased on a subscription model, which means that you never have to remember to buy replacement brush heads again—they’ll be delivered right to your door every 1-3 months.

Best For Short-Term Stain Removal

5. Non-Peroxide Whitening Strips

The results won’t be as drastic as peroxide-based products, but there are a few great brands of whitening strips that avoid peroxide altogether.

My favorite is Lumineux’s Whitening Strips, utilizing a coconut-oil based product for a 14-day treatment. (Plus, they won’t make your teeth sensitive!)

Best For Sensitivity-Free Whitening

The Best Intrinsic Whitening Method

Custom Whitening Trays

If you really want to whiten the enamel of your teeth and aren’t satisfied with the result of just removing external stains, I recommend just one choice: professional teeth whitening at your dentist’s office.

During this process, your dentist will take impressions of your teeth and create a custom tray that you can use indefinitely.

The biggest benefit of these—especially when compared to a product like Crest Whitestrips—is that the trays prevent the gel from touching and damaging the gums and other soft tissues in your mouth.

Additionally, custom trays have a better fit. As a result, all surfaces of your teeth will get coated with the whitening gel, leading to a more even result.

In comparison to whitening strips—which run around $40 per box and often, are used every few months, and must be regularly replaced—a custom tray costs around $250-300 and lasts forever, unless you have major dental work done.

Also, the peroxide gel you use in the trays is very inexpensive and can be easily purchased on Amazon as needed. My favorite whitening gels are Opalescense by ULTRADENT and Venus White Ultra Whitening Oral Care.

Best for Sensitive Teeth
Image alt

Venus White Whitening Oral Care

This is the whitening gel I use with patients, and I’ve found it results in the least sensitivity for patients who struggle with tender teeth and gums.

Buy Now

Image alt

Opalescence Teeth Whitening Gel

I’ve been recommending this brand for years, and it works great!

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Pro tip: Your dentist may recommend you buy whitening gel from his/her office, but it’ll often cost you three to four times more than simply buying it online.

The only major con to whitening with a custom tray is that the strong chemical used in them can cause sensitivity to hot and cold for about 24 hours after use.

To minimize any consequences as much as possible, be sure to always follow your dentist’s instructions, and don’t use it too often.

A Final Note on Intrinsic Whitening

There are some methods of teeth whitening I recommend avoiding entirely for safety reasons. These include:

  • Zoom/light/halogen/LED/laser whitening: These methods are ineffective and can destroy the nerves of your teeth.
  • Whitening mouthwash: Because whitening ingredients need to be held against the teeth for a sustained period of time in order to be effective, whitening mouthwash doesn’t work either. It also exposes your sensitive gums to harsh chemicals.
  • DIY whitening: Many DIY whitening recipes contain acidic ingredients like strawberry or lemon. These ingredients can wear away the enamel on teeth and contribute to decay and other dental issues.
  • Bleach: While peroxides in whitestrips and whitening gels do brighten your teeth, these aren’t actually bleach. Please don’t use actual bleach in your mouth, as it will do a lot of damage to anything it touches.

Stain Prevention: The Best Way to Keep Teeth White

If you really want to have the whitest teeth possible, Crest Whitestrips aren’t your best option.

Prevention is.

Here are a few options for preventing teeth from aging and yellowing too fast, while also catching stains before they stick:

  • Stay hydrated: Drinking adequate amounts of water during the day both rinses your mouth of stain-causing compounds from foods and drinks and prevents dry mouth, which can lead to decay and premature yellowing.
  • Limit staining foods and beverages: A glass of wine is good for the body (and soul), but try to limit the amount of time each day you eat or drink items that will stain your teeth. Time of exposure makes more of a difference than quantity consumed when it comes to staining.
  • Swish after staining foods and beverages: If you do consume any highly pigmented foods or drinks, you should rinse your mouth with water immediately after. Brushing is a good idea, too—just be sure to wait 30-45 minutes, as enamel may be more vulnerable to erosion just after eating or drinking.
  • Get regular cleanings: Allowing your dental hygienist to remove tartar and calculus from your teeth every six months is a great method to prevent tooth decay that may lead to premature yellowing.
  • Stop mouth breathing: A dry mouth is a major cause of tooth decay and aging teeth. Mouth breathing is a major cause of dry mouth, but practicing nasal breathing during the day and using mouth tape at night can help reverse this dangerous habit. Plus, if you’re a mouth breather, you’re thickening the biofilm on your teeth faster than normal. That means water can’t be as useful a buffer to stop your teeth from being stained.
  • Can’t mouth tape? Try a retainer: Some CPAP users, as well as those with chronic allergies or other breathing abnormalities, might not be able to mouth tape regularly. To protect your teeth from mouth breathing, try wearing a clear retainer over your teeth to keep them moist. Talk to your dentist about being fitted.
  • Treat teeth grinding (also known as bruxism): If you grind your teeth, it’s important to get to the root cause of the issue. You may find that you’re grinding your teeth because of sleep apnea, a condition that is caused by a blocked airway during sleep. Grinding is your body’s way of opening up the airway, but it causes significant damage to the teeth, including early aging/yellowing.
  • Wear a mouthguard during sports: To limit the damage to your teeth caused by a sports injury, always wear a mouthguard while playing contact sports.

Final Thoughts on Whitening Strips

You may be considering using Crest Whitestrips or a similar at-home teeth whitening method. While there’s nothing wrong with wanting a brighter smile, be aware that whitening strips contain adhesives and whitening agents that can cause sensitivity to the teeth and gums.

Using a course of whitestrips every once in awhile (read: every few years) won’t do lasting damage. Overusing these whitening agents, though, can:

  • Damage your enamel
  • Cause increased tooth pain/sensitivity
  • Wreck your oral microbiome
  • Whiten unevenly, leaving yellow sections

To use Crest Whitestrips (or another brand of whitening strips) effectively and safely, follow these easy tips:

  1. Cut the strips so that they only touch your teeth, not gums.
  2. Don’t brush immediately before or after using the strips.
  3. Leave the strips on for only five minutes at a time.
  4. Never sleep in whitestrips.

Want to know about another whitening method I haven’t mentioned? Just ask me about it here.

Read Next: What Is the Best Whitening Toothpaste?

6 References

  1. Environmental Working Group (EWG). (2018). PVP. Retrieved from:
  2. Environmental Working Group (EWG). (2018). Carbomer. Retrieved from:
  3. Environmental Working Group (EWG). (2018). Hydrogen peroxide. Retrieved from:
  4. Environmental Working Group (EWG). (2018). Sodium hydroxide. Retrieved from:
  5. Mali, A. M., Behal, R., & Gilda, S. S. (2012). Comparative evaluation of 0.1% turmeric mouthwash with 0.2% chlorhexidine gluconate in prevention of plaque and gingivitis: A clinical and microbiological study. Journal of Indian Society of Periodontology, 16(3), 386. Full text:
  6. Nagpal, M., & Sood, S. (2013). Role of curcumin in systemic and oral health: An overview. Journal of natural science, biology, and medicine, 4(1), 3. Full text: