"Hey Doc, Tooth Whitening Doesn’t Work — I Tried It Before at a Beauty Salon”

This is something dentists hear here and there, and it’s a fair concern. When patients try whitening treatments that don’t deliver, it can feel like a waste of time and money. However, not all tooth whitening treatments are created equal — and understanding the differences can make all the difference.

Not All Whitening Is the Same

Tooth whitening treatments generally fall into three categories:

• Professional whitening by a licensed dental practitioner

• Over-the-counter (OTC) products, such as whitening strips or gels

• Unauthorized whitening, often done at beauty salons or purchased online

Each of these options uses some form of peroxide-based agent to whiten the teeth, but they vary widely in safety, effectiveness, and the concentration of active ingredients.

It All Comes Down to Peroxide Strength

The key ingredient in most whitening treatments is either hydrogen peroxide or carbamide peroxide. In essence, these whitening agents break down stains in your teeth to brighten your smile.

Professional whitening uses high concentrations of peroxide, and the process is closely supervised by a dentist to ensure safety and results.

OTC products contain lower concentrations — they can work, but the results are often limited or take much longer to show.

Unauthorized treatments, such as those offered at beauty salons, typically fall into a grey area. The concentration of peroxide may be very low (which means it’s ineffective), or dangerously high (which risks damaging your gums and teeth). In many cases, you simply don’t know what’s being applied — and that uncertainty is a red flag to be aware of.

When Whitening Goes Wrong

Sometimes patients may get chemical burns on their gums and lips — a result of poorly applied or overly strong peroxide gels. Others complain that the treatment has no effect at all, often because the gel is too weak or improperly stored.

What’s worse, many of these treatments are advertised using dramatic “before and after” photos that may not be as real as they seem. Sometimes, the “whitened” look is simply due to dehydration — when the teeth are left exposed to air for a prolonged period (often with a gimmicky blue light), they appear whiter temporarily; but the effect fades once the teeth rehydrate.

In other cases, the photos may be altered through filters or white balance adjustments (see below). One trick to tell if the photo has been adjusted is to compare the colour of the gums. If the gum colour between before and after photos don’t match, the whitening is likely due to differences in the colour temperature, and not true whitening.

Trust Your Teeth to a Dental Professional

Tooth whitening, when done properly, can be safe and effective. A dentist can assess whether your staining is external (on the enamel) or internal (within the tooth), and tailor the treatment accordingly. We also protect your gums with barriers and use scientifically tested gels in safe concentrations — all while monitoring your comfort and results.

If you've had whitening done before with little to no effect, don't be discouraged. It doesn't mean whitening doesn’t work — it could mean the method used wasn’t ideal.

So What’s the Bottom Line?

Whitening your teeth isn’t about chasing the cheapest option — it’s about doing it right.

If you’re serious about getting a brighter smile, skip the salon chair and have a chat with your dentist. You’ll get expert advice, safer treatment, and results you can actually trust.