Hismile PAP+ Whitening Pen Review By Dentist

Written & Reviewed by Dr David Chen

This is my personal review of the Hismile PAP+ Whitening Pen. I’ll be giving you my subjective thoughts about what it’s like to use it as well as the objective scientific facts about whether or not the alleged claims work or not.

Hismile PAP whitening pen - pen next to box
Hismile PAP+ Whitening Pen

Yes, I am a dentist so don’t skip the section about how this whitening pen works because I will be explaining the nitty gritty details. Our goal is to help you in deciding whether or not this whitening toothpaste may be worth a try.

Disclaimer: If you make a purchase after clicking one of our links, we may earn a commission.


The PAP+ whitening pen by Hismile is a teeth whitening product that delivers the bleaching gel onto your teeth with a pen brush.

The best part of it is that it can whiten your teeth without causing teeth sensitivity since it uses phthalimidoperoxycaproic acid (PAP) instead of hydrogen peroxide (HP). It also helps that it is formulated with multiple desensitizers in it.

Hismile PAP whitening pen - box laying horizontally

Hismile is actually the first company to utilize PAP as a hydrogen peroxide alternative whitening agent. For that alone, we personally give them two thumbs up for their innovation.

Their product design team is on point because the packaging is very aesthetic looking.

Featured benefits

The primary selling point for the Hismile whitening pen is that it can whiten your teeth without using peroxide and it can do so without sensitivity. In other words, it can be used on a daily basis without worrying about overdoing it and causing teeth sensitivity.

List of benefits:

  • Gently lift stains
  • Great for on-the-go
  • Sensitivity free
  • Fastest whitening pen on the market
  • Safe for enamel and gums

We will explain how all of these benefits work in a later section.

Directions for use

The first time that you use this product, you must click the button multiple times until the formula reaches the brush tip. Then every subsequent use afterwards, you do not need to click the dispenser as much before you can begin using it.

How to use it:

  1. Dry teeth thoroughly.
  2. Smile to reveal teeth.
  3. Click to dispense bleaching gel onto brush tip.
  4. Brush a thin layer of gel onto teeth.
  5. Wait 30 seconds before closing mouth.
  6. Avoid eating or drinking for 10-30 minutes.
  7. Use as often as needed.

Product specifications

Net weight0.1 oz (3 ml)
Dispensing mechanismClicking pen style brush
Whitening agentPhthalimidoperoxycaproic Acid
Remineralization agentHydroxyapatite
DesensitizerPotassium Citrate
Technical specifications of Hismile PAP+ toothpaste


This PAP+ whitening pen from Hismile has a total of 21 ingredients.

Hismile PAP whitening pen - ingredients label
Ingredients label

Whitening agent:

  • Phthalimidoperoxycaproic Acid (PAP) – chemically oxidizes (bleache) tooth stains.

Remineralization agent:

  • Hydroxyapatite (HAP) – prevents cavities and teeth sensitivity
  • Ammonium Acryloyldimethyltaurate/VP Copolymer – helps maintain enamel integrity after bleaching


  • Potassium Citrate – reduces teeth sensitivity.

Stain and tartar prevention:

  • PVP – prevents stain molecules from sticking onto teeth.


  • Sodium Saccharin – sweetener
  • Mentha Piperita – peppermint oil


  • Titanium Dioxide – gives white coloring
  • Mica – mild abrasive which gives white coloring
  • Tin Oxide – color brightener to give white color

Raises toothpaste pH:

  • Sodium Phosphate – pH adjuster
  • Disodium Phosphate – pH adjuster
  • Potassium Hydroxide – pH adjuster
  • Monosodium Citrate – pH adjuster and preservative


  • Water
  • Glycerin – humectant (prevents drying out).
  • Sodium Gluconate – increases lathering
  • T-Butyl Alcohol – solvent
  • PVM/MA Copolymer – helps maintain ingredients on enamel surface
  • Xanthan Gum – gives the toothpaste body.


The Hismile PAP+ whitening pen comes in a vibrantly packaged rectangular cardboard box with bold pink and white colors. It is very eye-catching and aesthetically pleasing because I must say that I really like how it looks design-wise.

The packaging comes with security sealed tape on the top of the box. The bottom is just glued and without a tape.

After opening the box, you can find the pen inside with nothing else. There are no additional contents inside of the box aside from the pen.

To begin using it, all you have to do is pull off the cap. It isn’t a twist off nor is it a a flip cap. You simply pull it off which will then reveal the bristles of the pen brush.

I think it’s really neat that the whitening pen can still be stored in an upright vertical position. Although it is meant to be carried with you on the go if you wanted it to be.

One last interesting point to note is that the Hismile pen is relatively see-through so you can actually see the pen clicking mechanism as well as the reservoir for the whitening gel.

Hismile PAP whitening pen - see through showing clicking mechanism
See through pen shows clicking mechanism

My experience

My whitening experience with the Hismile PAP+ whitening pen was mixed because I had high expectations but it was different from what I had imagined.

First. I had to click the pen about 30-40x during the initial use before the gel finally dispensed onto the brush tip. For a moment I was worried that it may have been empty but thankfully it came through!

Hismile PAP whitening pen - clicking pen to dispense
Click to dispense

Second. I was expecting it to taste extremely sweet like their other products but it was more sour than sweet to me. Maybe if you like sour foods this would be up your alley?

Nonetheless, below is a concise summary of what I thought of it.

SmellHerbal medicinal
TasteSlightly Sour
TextureThin liquid
SensitivityNo sensitivity or discomfort
Summary notes from using the Hismile whitening toothpaste


The color of the PAP+ whitening gel is white. I painted it on my finger to show you what it looks like as well as how it looks when dispensed onto the brush tip.


It smells very medicinal to me but not in the synthetic kind of way. It’s more along the lines of an herbal-like medicinal smell.

I was expecting it to be sweet like their other products (v34 purple toothpaste and their PAP+ whitening toothpaste) but it smelled like a whitening product rather than candy.


The body texture of the whitening gel is similar to all of the other whitening products. It’s gel-like so it isn’t runny like liquid water. This is to enable it to stick onto your enamel.


As I brushed the whitening gel onto my teeth, it had a slight sour/acidic taste to you. You can definitely tell that this is “whitening gel” and that it wasn’t food from the taste profile.

I mean, when have you ever had a food-like tasting whitening product?

Nonetheless, I did feel slightly let down because I expecting it to be very sweet tasting because the previous two Hismile products (v34 colour corrector and pap toothpaste) that I reviewed tasted sweet like candy. As a matter of fact, their toothpaste was sweet enough that I would mistake it for dessert if no one told me what it was.

Hopefully in the future they can figure out a way to make their whitening pen with the same level of sweetness as their toothpastes. Then again that may not be wise because it may encourage people to try to eat it.


After brushing on the whitening gel, it didn’t really leave much of a residue on my teeth, which was quite different from my experience with the colgate whitening pen.

If you look at the photos above, maybe there was an ever so slight frosty color but that was about it.


I had absolutely zero discomfort and sensitivity as I was using the Hismile PAP+ whitening pen and also afterwards. There weren’t any changes so to speak. A lot of whitening products tend to cause sensitivity but this one did not.

Pros & Cons


  • Peroxide-free whitening
  • No teeth sensitivity
  • Enamel safe
  • Can be taken on the go
  • Aesthetic design


  • Unknown whitening concentration.
  • Feels like I need to click more for this to dispense gel vs other whitening pens.
  • Not sweet tasting.

What I like

Here are some things that I like about this PAP+ whitening pen from Hismile.

  • Beautiful product design. The packaging and overall design of the pen is highly aesthetic at least in my opinion. You can tell that Hismile spent a lot of their R&D budget on designing it.
  • Innovative. It’s innovative because they managed to create a product that can bleach your teeth without the use of peroxides and free radicals.
  • Remineralizing. It’s interesting that they decided to put a remineralization agent, hydroxyapatite in the whitening pen. That is good because it does help reduce teeth sensitivity.
  • Anti-sensitivity. There are two anti-sensitivity agents in this whitening product, potassium citrate and hydroxyapatite. Due to having both of them, the bleaching process should be discomfort-free.

What I dislike

The two main qualms that I have with this PAP+ whitening pen is the unknown concentration of the whitening agent and also the taste.

  • Non-sweet taste. I was really expecting the Hismile pen to taste as sweet as their purple toothpaste which was absolutely delicious but it ended up being sour. Really unsure why they didn’t use the same flavor formulation as the purple toothpaste.
  • Unknown bleaching concentration. The efficacy of whitening gels are highly reliant on the concentration. Most professional in-office products have upwards of 30-40% concentration while OTC ones are in the single digits. There is no concentration listed for the Hismile whitening pen!

The images above are examples of how the colgate optic white toothpastes have a 2%, 3%, and 5% whitening concentration. The in-office opalescence BOOST is 40%.

What remains a question mark is what percent PAP is the Hismile pen?

Does it work?

The alleged claims of the Hismile PAP+ whitening pen are that it can whiten your teeth without peroxide and without sensitivity. Yes, both claims are in fact true.

Studies which support whitening efficacy of PAP (Phthalimidoperoxycaproic Acid):

  • A study by Hismile researchers found that PAP+ was superior to hydrogen peroxide in whitening teeth in terms of color change as well as enamel safety.
  • Another study found teeth whitening with PAP was safer and more effective than peroxide based whitening products.

In summary, the PAP+ whitening pen from Hismile does work in making your teeth whiter without the associated sensitivity.

We will explain the mechanisms, which make this possible below.

How it whitens teeth

PAP whitens teeth by oxidizing teeth stains but does so without the use of free radicals. That is a departure from hydrogen peroxide which relies on oxidizing free radicals.

PAP oxidizes the conjugated double bonds of stain molecules via epoxidation.

  • PAP converts the carbon-carbon double bond into an epoxide.
  • Epoxides look distinctively like a triangle on molecular formulas.
  • End result is that the double bond has been converted to a single bond.

The mechanisms below show the process by how chromogens (stains) get decolorized, aka become whiter in color.

Credit: Mauro Pascolutti and Dileusa de Oliveira

Ultimately, when stains lose double bond it results in a whiter color/shade. Reason being when they lose double bonds, they will absorb less light and reflect more of it. Thus, these dark colored chromogens will become lighter in color.

How peroxide whitens teeth

Hydrogen peroxide oxidizes tooth stains by forming potent oxidative free radicals when it decomposes. These free radicals can diffuse through the tooth enamel and dentin while bleaching away all of the colored stains.

hydrogen peroxide decomposition to radicals - reaction equations
Peroxide decomposition mechanism

These free radicals convert the double conjugated bonds of stain molecules into single bonds.

Hydrogen peroxide oxidation of double bonds
Credit: Clifton Carey

Essentially, both HP and PAP decolorize tooth stains by oxidizing double bonds and that makes them whiter but they use a slightly different chemical reaction to do it.

How it prevents sensitivity

Teeth sensitivity is a common side effect of teeth whitening. According to the American Dental Association, sensitivity will appear within a few days of starting treatment.

The advantage of using the Hismile pen is that it contains two desensitizers, which help to reduce discomfort during the bleaching process.

  • Hydroxyapatite. Although hydroxyapatite is more commonly known as a fluoride alternative, it has anti-sensitivity effects. Molecules of HAP can physically block exposed open dentinal tubules which helps prevent the nerve from being stimulated.
  • Potassium citrate. Toothpastes with potassium citrate can help depolarize the tooth nerve thus alleviating sensitivity. The desensitizing mechanism is similar to the more commonly found potassium nitrate which is in the sensodyne pronamel toothpastes.
schema of hydroxyapatite reducing dentin hypersensitivity
Credit: Lijie Chen, Suma Al-Bayatee, Zohaib Khurshid, Amin Shavandi, Paul Brunton and Jithendra Ratnayake

Due to the combination of these two desensitizing agents is the reason why Hismile can boldly claim that they can whiten your teeth without sensitivity.


Overall I think the Hismile PAP+ whitening pen is a good teeth whitening product if you choose to use it.

The best part about this product is actually the fact that they use 2 desensitizers in it so that you can whiten and use their product more. Most people are forced to stop the whitening treatments whenever their teeth get sensitive but this is not a problem with Hismile.

Hismile did a fabulous job with the marketing and product design. Although personally for me, what I wish they had done was make it taste similar to their purple toothpaste or PAP+ whitening toothpaste.

Those two were much more delicious tasting. Then again, I’ve yet to encounter a teeth whitening product that tastes like food!

But I’m very hopeful that Hismile will at one point make the breakthrough. They’ve been incredibly innovative with their products thus far.

As always, I’m impressed with their level of creativity and innovativeness. And that concludes the review of the Hismile PAP+ whitening pen by your favorite dentist.


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