In testing, this gel was easy to put on and caused no discomfort during or after application (including for those of us with sensitive teeth). The mouthpiece fit well and stayed in place, thanks to the fact that it’s soft and flexible, not rigid. We also loved that the tray could be plugged into our smartphones, so we could get up and move around the house while we waited out the whitening time. Teeth whitening products, in general, are known to cause sensitive teeth. As such, you must choose a teeth whitening pen with a lower peroxide level. This level will depend on your teeth’s sensitivity. On the other hand, hydrogen peroxide breaks down faster than carbamide peroxide and lightens stains in as little as 30 to 60 minutes. But it doesn’t produce much effect until the next application. 2 When choosing a teeth whitening pen, look at how many uses it provides. You want a pen that can give you enough treatment for the money you’re spending.

Still, if you know your teeth are particularly sensitive, you can aim for a whitening product with 3 to 10 percent carbamide peroxide, says Dr. Izhaky.Some teeth whitening pens can be cheap, but they only contain a small amount of product. However, other pens can be more expensive but contain more serum. This means you’ll get more value for your money when using them. Brand Reputation Initially, we couldn’t leave the tray in for the recommended 15 minutes because it was so uncomfortable. But over time, we did get used to it. The best part was that our teeth whitened. Even though we only left it in for about eight minutes, our teeth went up a full shade. It hurt, but the pain was worth it in our eyes. We also started with the highest concentration possible, which we wouldn’t recommend if you have sensitive teeth or have never whitened your teeth before (in that case, you may want to start with the lowest concentration and work your way up from there).

Pro tip: Avoid rinsing your mouth, eating food, or drinking beverages within the first 30 to 60 minutes (if using hydrogen peroxide) or within 2 hours (if using carbamide peroxide) of use. Are Teeth Whitening Pens Safe and Effective? We did experience a bit of a funny aftertaste in the few minutes following application, but this isn’t unusual for whitening products, and it went away shortly after. We also like that the pen features a brush-tip applicator, which helps to evenly distribute the serum and get into the crevices between the teeth. Plus, after using it as directed, there was still plenty of product left in the pen that could be used for touch-ups down the line. Carbamide peroxide releases 50% of its whitening effects in the first two hours of application. These effects can last for six more hours afterward. 1 Pro tip: Consult a cosmetic dentist before using a teeth whitening pen. This is especially true if you have sensitive teeth, dental restorations, dark teeth stains, a single dark tooth, or fillings and crowns. Advantages of Teeth Whitening Pens Other kinds of teeth whitening products exist besides pens. They are available over the counter and contain hydrogen or carbamide peroxide as a whitening agent. These include:

The NewMouth editorial team analyzed dozens of products available today to determine the available products. Although many carbamide-based whitening pens have the same 35% formulation, manufacturers only recommend using them for 7 to 10 days which is within the safe range. Per Dr. Kalasho, common whitening ingredients that work well for at-home use are carbamide peroxide and hydrogen peroxide. For carbamide peroxide, look for a percent of around 35 percent; for hydrogen peroxide, you’ll want something with a 10 to 15 percent concentration. The main reason to opt for a whitening pen and not a more comprehensive kit is convenience, and this pen by AuraGlow is nothing if not convenient. You won’t get mega-white brightening results here—we noted it lightens maybe a shade, at most—but you will get an easy and painless application process and the ability to easily whiten minor stains on the go.

POWERED BY HYDROGEN PEROXIDE: The same teeth whitening ingredient dentists use for a whiter, brighter smile. We did find the whitening process to be slightly less comfortable; the solution was pretty tasteless, and our gums experienced some discomfort. Swallowing was also awkward because the solution can produce excess saliva, but you aren’t supposed to swallow the solution. However, the application time here is only 10 minutes, so we thought this was a totally manageable inconvenience for the amount of time needed to whiten. Team Byrdie interviewed two experts to better understand what's important when finding the best teeth whitening pen. These sources included:

SmileDirectClub recommends using the whitening pen twice daily for fuller results, which should take just one week to see. Application takes five minutes—and the cool mint flavor makes the wait even easier. We also like that this kit includes lip balm as teeth whitening can sometimes chap lips during treatment—so you can freshen up both simultaneously.