Directions for wearing Crest Whitestrips® - Part 2

- How long are they worn? / How often? / Post-treatment wrap up. / Difficulties with uneven whitening.

This is the second half of our instructions for using Crest Whitestrips® products. On this page we cover:

  1. How to perform individual treatments. - How long are the strips left on? How often are they used? What activities can you do while wearing them? Possible solutions for uneven whitening.
  2. Steps to take when terminating your treatment session.


(Part 1 of our directions outlines how to get ready to perform treatments and how to place the strips.)

4) Performing treatments using Crest Whitestrips®.

A) How long should you leave your strips on?

Once you have your strips positioned, your bleaching session has begun. So, take a look at your clock and start timing.

!! The recommended treatment time varies with each Whitestrips® product.

While the way you use all Whitestrips® is essentially the same, the application times for the various product versions are entirely different. As you can see in the table below, times range from 5 minutes all of the way up to 2 hours.

A part of this difference is due to the fact that whitening strip products can vary substantially in the concentration of peroxide that their whitener contains. And that means staying within your product's guidelines is not just a "best results" but also a safety and side effects issue too.

In all cases, you must refer to the instructions that have come with your specific product for directions about how long and how often your strips should be worn.

Application times for different Whitestrips® products.

5 minutes, once a day strips.

Crest 3D White Whitestrips® Gentle Routine Teeth
Crest 3D White Whitestrips® Stain Shield

Most Crest Whitestrips are worn for 30 minutes.

Many Whitestrips products are worn for 30 minutes. Check your instructions.

30 minutes, once a day strips.

Crest 3D White Luxe Whitestrips® Glamorous White
Crest 3D White Whitestrips® Professional Effects
Crest 3D White Whitestrips® Advanced Vivid
Crest 3D White Whitestrips® Vivid

1 hour, once a day strips.

Crest 3D White Luxe Whitestrips® Supreme Flexfit
Crest 3D White Whitestrips® 1 Hour Express

2 hours, once a day strips.

Crest 3D White Whitestrips® Intensive Professional Effects

Note: Products, as well as product names and versions, can change so be sure to check your instructions.

You can always wear your strips for less time.

The treatment times stated above are the maximum duration your strips should be left on. You can always wear your strips less. For example, you might do so as a way of managing side effects.

The trade-off is that you'll get less whitening effect per strip. And that means to reach the same whitening endpoint, you'll have to purchase additional quantities of product.

Crest Whitestrips.

One pair Crest Whitestrips (upper/lower).

Number of treatment sessions.

The number of applications per day shown above seems to be Crests® standard recommendation for use. Information on their website states that their 3D White Whitestrips® Vivid, Advanced Vivid, and Professional Effects products can be used up to twice a day (30 minute application time each session).

This same page also states that 3D White Whitestrips® Stain Shield and Gentle Routine are only once-a-day products. We don't have information on other types of Whitestrips®. We discuss this topic in greater detail below.

What happens if you miss a session?

Missing one of your treatment sessions is of no concern, whether it's one complete day's, or a day's second application.

The whitening results you do ultimately get does depend on the total number of treatments you perform, so you will need to make any missed one(s) up. But whether you complete your whitening process precisely as prescribed, or just somewhat close to it, will make no difference.

B) What activities can you do while performing your treatments?

You can do pretty much anything you want while your strips are in place, so long as it doesn't dislodge them. And if you've chosen one of the Advanced Seal® or FlexFix® style of strips, you may not be limited much at all.

  • For obvious reasons, you shouldn't smoke or eat while performing treatments. Drinking doesn't make an especially great choice either. Even if the strips stay in place (which Crest® says some designs will, use above link), the liquid might dilute the whitener to some extent.
  • Wearing your strips during times when you'll need to do a lot of speaking, especially in public, might be problematic. You'll just have to experiment. You should not wear strips when you sleep.


No matter what you decide to do, it's a good idea to check your strips every once in a while to make sure that they are still in place. And, for reasons discussed previously, if you do find that you need to touch your whitening strips, make sure that you rinse your fingers off afterward.

C) Excessive salivation can be a nuisance.

Anytime you place something in your mouth, your body will respond by increasing its flow of saliva. (Your mouth gets confused, it thinks that the item is possibly food.)

Wearing whitening strips is no exception to this rule, and the increase in saliva can be a nuisance. The build up of liquid tends to make treatments a bit yucky. It can also make it difficult to keep the less adherent style of strips in place (especially the lower ones).

What can you do?

There aren't a lot of solutions for this problem. But the good news is that your response should tend to diminish over time.

Focusing on some other task (rather than the fact that you have strips in your mouth) can help to make things more tolerable. So, maybe your treatment time would also be a good time to balance your checkbook, wash the dishes or mow the yard.

You may notice foaming.

When saliva reacts with hydrogen peroxide (the active ingredient found in a WhiteStrip's® whitener), oxygen is released. The result is the formation of bubbles and foaming.

Some level of bubble or foam formation is a common experience for anyone performing a whitening treatment. However, if wearing your strips tends to trigger an increase in salivary flow, the effect can be even more noticeable.

5) Terminating a bleaching session.

A) Removing teeth whitening strips.

At the end of its allotted time period, a treatment session is terminated simply by removing your strips.

That's easy enough to do, just peel them off. (With Advanced Seal® and FlexFix® strips you may be surprised by how firmly they're anchored.)

Disposing of your strips.

You'll want to discard your used strips carefully. That's because some of the hydrogen peroxide whitener (bleaching agent) on them may not be totally depleted.

  • Dispose of your them in a fashion and manner where they are unlikely to come into contact with anything that they might irritate, mar, stain or blemish. This includes you, other people, pets and objects.
  • Always wash your hands after handling teeth whitening strips.

B) Clean your teeth and gums.

Once your strips have been removed you should rinse, wipe or brush away any whitener residue that remains on your teeth or gums.

When doing this you may notice that you experience some post-treatment sensitivity.

You should brush your teeth after removing your whitening strips (Crest Whitestrips).

Any residual whitener can be brushed away.

Be sure to wash off your fingers, toothbrush, etc... after you've finished cleaning the residue away.


6) Treatment frequency.

A) Multiple applications.

As mentioned above, information on Crest®'s website states that their 3D White Whitestrips® Vivid, Advanced Vivid, and Professional Effects products can be used up to twice daily, 30-minutes application time each session.

The advantage of performing more than one treatment per day is simply that your whitening process will take place more rapidly. The trade-off is if you do, whitening side effects are more likely to occur (see below).

Can you perform treatments back to back?

Yes, with Whitestrips® twice-a-day products it's permissible to perform one treatment immediately after the other.

  • Remove your first set of strips.
  • Remove (wipe, brush, rinse) any residue they've left behind. (See "Removing Strips" section above.)
  • Apply your day's second set of strips and wear them for their prescribed amount of time.


B) Spreading your sessions out can help to minimize side effects.

There can be good reason for you not to perform multiple whitening treatments each day, or even treatments on consecutive days (when allowed by your product).

A person's potential to experience whitening side effects correlates directly with their exposure to the whitener within a specified time frame. As a way of helping to minimize or control side effects, allowing extra time between sessions can be beneficial.

C) Is it OK to wear teeth whitening strips longer than their directions state?

No, it's never a good idea to use any tooth whitening product in a manner that lies outside the guidelines specified in its directions, teeth whitening strips included.

  • A unique feature of whitening strips is that it's the manufacture that dispenses the quantity of whitener, not the end-user.
  • That implies that through testing, they have determined what amount of whitener is required to remain effective for the duration of the recommended treatment time, yet not be likely to create side effects.


So, if you extend the duration of your treatments ...
  • You are unlikely to gain any overwhelming whitening benefit, because the whitener tends to become depleted during the recommended application time.
  • But you will be placing yourself at somewhat greater risk (although probably minimally) for experiencing side effects (primarily tooth or gum sensitivity).


Can you reuse a strip?

No, there would be no purpose in doing so. It's expected that the active ingredient found in a strip's whitener (hydrogen peroxide) will be full depleted, or nearly so, at the end of its recommended application.

D) How many whitening kits can you use?

Generally speaking, Crest® suggests that using two whitening systems per year is the limit.

  • An exception to this could be the situation where the person has experienced severe sensitivity with their first kit that was very difficult to resolve, or possibly even continues.

    If so, the use of a second kit is contraindicated. And what constitutes an appropriate whitening method for the person should be rethought.

  • Some cases might be appropriately treated using more than two kits. But exceeding Crest's® recommendation on your own makes little sense.

    Generally speaking these would be those cases performed under the oversight of a dentist. The oversight needed might be little more than discussing matters with them during your regular checkups.


7) Whitening difficulties.

a) White spots after treatments.

It's not terribly uncommon that when a person removes their strips at the end of their whitening session that they notice white spots or areas on their teeth.

These spots are not a cause for alarm. Crest® publications refer to them as temporary and state that they'll go away on their own after a few hours.

The cause.

The white spots form in areas where the tooth's enamel has become dehydrated (dried out). (Remember, your tooth has been under a plastic strip where saliva can't get to it.) As moisture is able to rehydrate the area, it's normal appearance will return.

b) Uneven whitening.

Some people may notice that their treatments have had the effect where some of their teeth or tooth areas have started to lighten more so than others.

Unfortunately, there can be a number of factors involved when this type of situation occurs. And this points out one of the main disadvantages of using an at-home method where no expertise or supervision from a dentist is involved.

Possible solutions.
  • As a first check, you should make sure that all of your teeth are covered over by and have the same degree of intimate contact with the strip during your treatments.
  • Assuming there aren't any overlooked dental restorations involved, the problem might be as simple as certain teeth or areas of staining are slower to respond than others. If so, over time the issue should tend to resolve itself.
  • If problems persist, you might halt your bleaching efforts and search for a way to just selectively treat the stubborn teeth to see if they will "catch up." As possibilities, you might cut up a strip and apply just pieces of it. Or consider using a whitening pen.




Topic Menu ▶  Using Teeth Whitening Strips


Treatment Frequency

This is a great site! Thank you for all the info that I couldnt find on the Crest website.

But I'm still not sure how long (# of days) I'm supposed to use the strips, and how often. I understand less frequent may help avoid side effects. But do I use it say every other day for a week? A month? Until I feel my teeth are white enough?

The instructions included with the strips said "use up to two kits per YEAR". The kit I have has 14 sets of two strips each. So that means 2 kits per year would be a total of 28 treatments per year. Can I use it every day, once a day for 28 days? I have the Glamorous White strips.

I got this from Costco so it came with 4 treatments of the one hour express strips. Can I use this in addition to the 28 max per year?

Hope I wasn't too confusing. Thank you for your advice! Aloha!



This would be our biggest concern with your post, the statement: "Until I feel my teeth are white enough?"

That's the problem with at-home products, the potential for over use, either accidental or when seeking unrealistic results.

Our response would simply be: What's the rush?

Here're the facts:

a) Whitening results generally correlate with the total exposure to the whitener (strips), whether that exposure is stretched out or compressed in time.

b) The exception to the above is the fact that for everyone only a certain level of lightening improvement is possible. Beyond that point, using more strips will not create further results but will still have the potential to cause side effects.

c) The potential for side effects correlates directly with the amount of exposure to whitener within a timeframe. Extending the time frame, reduces the potential.

If you're trying to avoid side effects, using strips every other day until all 14 sets in your kit have been used can make a good plan. If side effects crop up and you want to continue, let things settle down first and then try wearing the remaining strips even less frequently.

If with your first kit problems did occur, it makes no sense to continue treatment with a second kit immediately.

With dentist supervised treatments, using the equivalent of two kits back to back would likely be tolerated uneventfully by most people. But when on your own, you should error on the side of safety. Wait some weeks (at least until any residual sensitivity has disappated) before starting up again.

In regard to the express strips, the concentration of whitener on them will be greater than with your others. So, expect more potential for side effects when wearing them.

It seems to us the way the 4-treatment express kit is marketed, it's intended to be roughly equivalent to the 14-strip Glamourous kit that you have. So consider the express kit as your second annually-allowed kit.

Beyond that, tell your dentist what you've been up to at your next check up and let them help you decide if using more kits seems a reasonable choice.

Treatment Frequency

Thank you for a very complete and quick response. I'm not in a rush at all but am anal about following directions and reading the fine print when using any new product. Except the fine print and directions for this weren't very clear IMHO. So I really appreciate your help. All my questions have been answered now. Thank heavens for your website! Mahalo and aloha! ☺️

Harmful to swallow?

It says it creates more saliva so can you swallow your saliva during the treatment or do you have to spit it out?


Best practice would be to spit it out. Swallowing bleaching compounds will tend to create the side effect of throat irritation.


The only difficulty I have had is the amount of saliva produced, which I did not want to swallow. And the more you think about this, the more you produce. So, what worked for me was, once the strips in place, folding a square of absorbent kitchen paper into a pad, placing it over my lower teeth with my tongue resting on this, and replacing the pad from time to time. This absorbed any saliva and removed the problem for me. Not an attractive look, so obviously only useful in fairly solitary confinement!

Would using one strip a week

Would using one strip a week (3D White Luxe) have a positive result or do they have to be used closer together?

That should work.

Theoretically, teeth respond to the total amount of whitener they are exposed to.
So whether you use (say) 14 strips at a rate of once a day or once a week, the total cumulative whitening effect should be the same.

However, using them once a day will likely produce results fast enough that you notice that your teeth are lightening. With a once-a-week rate, you likely won't notice much affect at all but one will have taken place. Sporadic use of strips might be considered "maintenance" whitening.

Gentle 3D Whitening Strips

I have sensitive teeth that have become yellowed over the years. I've never had my teeth professionally whitened, nor do I have caps/veneers/bonding. I started the daily use of the gentle strips 2 and 1/2 weeks ago. I can see a difference in my teeth: they are no longer yellow. However, they are not "white"; my three questions are these: 1. Will I continue to see an improvement in the color as I complete the 28 days? 2. My front two teeth don't seem to be getting as white as the other teeth, even though they were not stained any differently and I do not have anything artificial on them: any explanation/advice on this? 3. After I complete the 28 days, what should the maintenance schedule be (using gentle strips again)? Once a week? Once a month? One full week every other month?

Thanks so much for your help. Incidentally, I do not smoke, drink coffee or tea, or drink red wine.

It's certainly possible that

It's certainly possible that you will experience a continued whitening effect. The whole whitening process is simply cause and effect (the greater exposure to the peroxide (concentration, time), the greater the whitening effect (speed, level of results).

Sooner or later a point is finally reached where no more whitening effect is possible (the teeth have lightened as much as they will).

In regard to your front teeth, there are just so many possible factors and variables it's impossible to know exactly what is occurring. (Are all teeth getting an equal exposure to the strip, is it simply some teeth need a greater/longer exposure before showing results, ...)

If this is of utmost concern, you might consider trimming strips so only certain teeth are treated, in an attempt to get them to "catch up" with your other ones, and then proceed from there. It may be tedious and a waste of materials but then at least you are more in control of things. Otherwise it's likely that the uneveness will take care of itself over time.

As far a touch ups go, you might just wait to see how noticeable any relapse that occurs is before treating it.

As compared to most other Whitestrips products Gentle Routine strips create a relatively minimal exposure to peroxide (relatively low concentration whitener, short treatment duration). (Hence the reason they are less likely to cause sensitivity.) So using a touch up regimen of once or twice a month would seem reasonable and unlikely to cause unmanageable side effects for you.

Thank you so much for your

Thank you so much for your advice and quick response! I will take your advice and see how it goes!

Discomfort Issue

Can I wear my strips for longer?


The whitener on a strip will deplete as time goes by. And while some whitening potential probably remains after the recommended time frame stated in the instructions, it's unlikely to be much. And for that reason wearing your strips for longer wouldn't be expected to provide much extra benefit.

Wearing your strips longer also exposes your gum tissue to the whitener for a longer period of time and therefore might make experiencing side effects more likely.

LIght application

Do I remove the strips before applying the light?


We totally get your confusion, and are confused about that point too:
1) On the Crest website, the instructions are vague and imprecise.
2) In the comments on that page, some comment posters state they have worn the strips for an hour first, then afterward applied the light.
3) We called the Crest helpline. That person said the light was applied to the strips for a part of the time while they are worn. But this person seemed unsure. They certainly didn't know the answer off the top of their head.
4) Since the Crest phone representative seemed confused, we decided to email Crest and get an answer that way. Unfortunately that response will take a few days. When we get an answer we will post it here.

With other whitening methods, the bleaching light is applied when the whitener is on the teeth.

Probably more important to state, we'd be of the opinion that the use of a light adds little if anything to the whitening process. It would be our guess/opinion that Crest's purpose in packaging a light with their strips is that it helps to sell more kits (is a gimmick), as opposed offering a scientifically proven technique that substantially adds to the whitening process.


We appologize for the delay on this. We heard back from Crest and here is what they stated:

Wear the strips for 1hour.
After 1hour, press and hold the two buttons on the light simultaneously to turn on the light then release. Then place the light on the top strip until the light automatically turns off after a few minutes. Repeat on the bottom teeth.
Remove the light and strips when finished.

Our personal opinion, we'd have little faith that the use of the light plays a significant role in the whitening process.


I both a big box of 3d WHITESTRIPS in April 2013 and still I didn´t use them: are them still good to start the treatment? Thanks,


It seems fairly unlikely that using the strips would be effective.

The whitener found on whitestrips is hydrogen peroxide, and this form of peroxide in particular poses challenges for manufacturers in delivering a potent product, much less some years after its manufacturing date.

Since it's just a matter of the whitener being depleted, there should be no problem in using the strips to see what results you get. Just don't expect much.

Bought pkg. of combo crest 3D glamorous white & one hour express

Got combo pkg. I'm confused, do you use one and then the other, in what order or use them completely independent of each other?


What you have is two equivalent products. Either is intended to provide a similar whitening process and create a similar level of results.

Whitening results are simply cause and effect, based on the total exposure of your teeth to the whitener.

The Luxe Glamours White product has a 9.5% hydrogen peroxide whitener that is on your teeth for 30 minutes a day, for 14 days.

The Express product has a 10% hydrogen peroxide whitener that is on your teeth for 60 minutes a day, for 7 days.

Both products will deliver a similar cumulative exposure of whitener to your teeth, and therefore can be expected to create a similar whitening result.

Using both products over the same time frame would equate to double treatments. That is not advised. Side effects would likely be a problem for you.

Choose whichever kit seems most attractive to you and use it alone. Save the other kit for somewhere later on down the line. Store the unused kit in a dark, cool place (your refrigerator).

crest professional effects

Bought 10 strips from e bay, I've used 5 so far without any visible results.. .. So disappointed. My teeth is still yellowish brown


WhiteStrips is a reasonable approach to whitening but not all types of staining are so easy to resolve.

You should finish the box and then discuss your experience with your dentist. Under their supervision they might suggest that you try another box (whitening is a cumulative effect). Or possibly they might feel that a tray-based whitening system might be more appropriate for your case.

Must I use all 14 treatments

I have the 3D Whitening Strips. My teeth have minimal yellowing and no stains. If I am satisfied with their appearance after 7 treatments, can I just finish the remaining treatments when I notice they are not a white again? And naturally before product expiration or is there a compelling reason to use all 14 treatments within a 30 day period? Thank you for this informative site.

Thanks for the question Patty,

Your thinking is correct. There's absolutely no reason to continue with treatments if you're already happy with the color change that's occurred.

It's so refreshing to hear from someone who evidently understands the difference between teeth that have been whitened and look natural, as opposed to those who aren't happy unless their efforts have reached a hideous level of white that never occurs naturally in human populations.

And yes, just anytime in the future use any number of the remaining strips as you feel is indicated.

FYI: Storing unused strips in your refrigerator is the best environment. Just in case you forget about having them, expired strips can be expected to work although less effectively. Using them is not harmful.


I have the one hour express strips, they come in a pack with several strips, I know you use one a day for one hour, but how long should i wait before I use another strip? the next day? the next month?


Per the Crest website for their "3D White 1-Hour Express Whitestrips":

"Usage: Apply once a day for 1 hour. Full results in 7 days."

So, their intended recommendation is a maximum of 1 treatment per day. But keep in mind that it's perfectly fine to use the strips less frequently.

Whitening teeth like this is simply cause and effect, nothing more. If after a few treatments your teeth are the color you're after, then call it quits. Put your remaining strips in the refrigerator (to maximize their shelf life) and use them for touch up whitening as you need them.

How many days do I use the Crest 3D White whitestrips?

I just bought the box today. I can’t find anywhere how many days to use the product. There are 21 days worth of the strips, do I use it for three weeks?


With the exception of touch up products, the intenion is that you use the included strips continually untill all have been used.

Of course it's always permissible to use fewer if you have reached the level of whiteness you desire or if side effects become a problem.

I had the white spots form on

I had the white spots form on my teeth and they did go away a few hours later.

Eating and drinking after treatment

With other teeth whitening products it recommends that you don’t eat or drink any coloured foods for up to 24 to 48 hours after each treatment. Is this the same with the crest luxe whitening strips?


Almost all teeth bleaching methods involve the use of peroxides, including Whitestrips. And peroxides can have an effect on the surface porosity of tooth enamel, which tends to make them more susceptible to staining until natural processes reverse the effect.

This effect would be greatest with high-concentration/one-visit treatments, like a dentist performs in their office.

So while what you state is a best practice for any bleaching method, implementing it with a low whitener concentration at-home product is difficult and of less concern. (If you're performing daily treatments, how do you abstain from dark foods and beverages for 24 to 48 hours?)

While it would seem a good idea to abstain from dark consumables for an hour or two immediately following your at-home treatment, in reality that level of staining that occurs is probably only a minor burden and inconsequential to the duties of your next strip.

Supreme Flexfit - How often

The instructions say once a day for a strip, but nothing about the timing pattern. The Supreme Flexfit has 21 applications, are they used 21 straight days? Or is it once a week, or some other sequence. Since the instructions recommend only using no more than once a year, it is odd that no instructions on how often to use each treatment. Thanks for any help!

* Comment notes.


The webpage describing their 'Crest 3D White Supreme FlexFit Whitestrips' product says:
"Usage: Apply once a day for 1 hour. Full results in 21 days."

Especially for new users, it's commonplace to start with a reduced schedule (like every other day, or even more) just to make sure side effects (like tooth sensitivity) aren't going to be a problem for you.

Since teeth whitening is simply dependent upon the total dosage of whitener your teeth are exposed to, doing treatments every day vs. every other day will give the same end result, it just takes longer.

Thanks for your response! I

Thanks for your response! I read the usage part and made the assumption of 21 straight days, but with the advertised results lasting over a year, I questioned the 21 straight day approach. I also appreciate your comments on the reduced schedule, since I am a new user. Your last paragraph was most helpful in setting my expectations. Thanks for taking the time to advise and counsel, I found this extremely helpful!

3D whitestrips

Question- how soon after you remove the strips can you brush your teeth.

* Comment notes.


It's OK to brush right after a WhiteStrips session. Use a regular soft-bristled brush and be gentle.

Reading this literature.

I found this to be most helpful.
Thank you for taking the time to answer the questions.

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