The only question that matters
Is your discolouration extrinsic — a film on the surface from coffee, tea, wine or tobacco — or intrinsic, meaning it's the actual colour of your tooth structure?
Surface-acting methods do nothing to intrinsic colour. Peroxide-based methods work on both but carry a sensitivity trade-off. Buying the wrong category is the single most common way people waste money here.
The comparison
| Method | Acts on | Typical timescale | Main trade-off |
|---|---|---|---|
| Professional cleaning | Extrinsic | One appointment | Cost and scheduling; doesn't touch intrinsic |
| In-office whitening | Intrinsic + extrinsic | One to a few sessions | Highest cost; strongest sensitivity risk |
| Custom trays (dispensed) | Intrinsic + extrinsic | Two to four weeks | Requires fitting; compliance-dependent |
| Peroxide strips | Intrinsic + extrinsic | One to two weeks | Uneven coverage; sensitivity for some |
| Whitening pens | Mostly extrinsic | Days | Effect is modest and short-lived |
| Whitening toothpaste | Extrinsic | Weeks | Abrasivity varies a lot between products |
| Purple-toned products | Neither — optical | Immediate | Colour correction, not a change to the tooth |
| Charcoal products | Extrinsic, abrasively | Days | Abrasivity is the mechanism; that's the concern |
Reading the marketing
- "Visibly whiter" is a claim about appearance and can be satisfied by removing surface film alone.
- "Enamel-safe" and "no sensitivity" very often indicate a non-peroxide formulation — which usually means extrinsic-only.
- "Clinically proven" on a consumer product is a claim about a specific study with a specific protocol. It's worth knowing which.
- Before-and-afters are taken under controlled lighting at two points in time. They are the least informative evidence available and the most used.
- Remineralisation ingredients are a separate benefit story from whitening, frequently sold in the same sentence as though they were one.
Where tracking helps
If you're going to spend money on this, the useful thing is a consistent measurement before, during and after — same light, same angle, same time of day.
That turns "I think it's working" into a slope. It also tells you the thing the marketing never will: how fast it reverts once you stop, which is the number that determines what this actually costs you per year.
Questions
None. ToothPal doesn't sell products and doesn't recommend treatments. It reads what your shade is doing so you can judge for yourself, and it points you at a dentist for anything that's a treatment decision.
If it works on your type of discolouration, yes — gradually. Expect a few points over weeks, not a jump. A jump usually means the lighting changed.
Extrinsic results revert as soon as the habits that caused the film resume. Intrinsic results last considerably longer but still drift. Tracking is how you find out your own rate.