Whitening strips can work, but only to a point. Strips that contain hydrogen peroxide can lift surface stains and lighten teeth by a small amount over a couple of weeks, while many of the peroxide-free strips sold in Australia mainly remove surface staining. They do not reach the deeper or uneven discolouration that professional whitening is designed for.
The ingredient list on the box tells you most of what you need to know. Here is how to read it, what results are realistic, and where strips fall short.
What is actually on the strip
A whitening strip is a thin, flexible film coated on one side with gel. You press it onto the front of the teeth, leave it for the time on the pack, then peel it off. Everything depends on what that gel contains.
In Australia, whitening products with more than 6% hydrogen peroxide, or more than 18% carbamide peroxide, can only be supplied by registered dental practitioners. That rule shapes the strips you can buy in a pharmacy or supermarket. They fall into three broad groups.
| Strip type | Active ingredient | What it can do |
|---|---|---|
| Peroxide strips | Hydrogen peroxide up to 6%, or carbamide peroxide up to 18% | Mild lightening of the tooth itself plus surface stain removal |
| Peroxide-free strips | Usually PAP (phthalimidoperoxycaproic acid) or similar | Mostly surface stain removal; limited evidence for lightening the tooth's natural shade |
| Colour-correcting strips | Pigments such as blue or purple tints | A temporary optical effect that washes off; no change to the tooth |
Only the first group whitens in the sense dentists mean: breaking down pigment inside the tooth. The colour-correcting kind works the same way as purple toothpaste: the tint masks yellow for a short while and then rinses away.
What results look like
With a peroxide strip used as directed, most people notice that their teeth look a little brighter after one to two weeks. The change is usually modest, and it is most visible on teeth with yellow, surface-level staining from coffee, tea or red wine.
The results are smaller than with professional whitening for three reasons. The gel is weaker. It is in contact with the teeth for a shorter time, often 30 minutes, compared with several hours or overnight in custom trays. And a flat strip does not wrap well around curved or crowded teeth, so the gel does not reach every surface evenly.
That last point is behind one of the most common complaints: patchy results. The middle of the front teeth lightens while the edges, the gaps between teeth and the areas near the gums stay darker. Our article on uneven or blotchy teeth after whitening explains why this happens and how it is usually corrected.
Where strips fall short
Strips only cover the teeth that show when you smile, usually the front six to eight on the top and bottom. Teeth further back are left untouched, which can create a visible step in colour for people with a wide smile.
They do not change the colour of fillings, bonding, crowns or veneers. If a front tooth has a tooth-coloured filling, whitening the teeth around it can make the filling look darker by comparison.
They also cannot do much for discolouration that sits deep in the tooth. Grey or banded staining from certain medicines, a single tooth that has darkened after an injury, or white and brown developmental marks behave differently from surface staining. The difference between the two types is set out in intrinsic and extrinsic tooth staining.
Are whitening strips safe?
Strips sold legally in Australia are generally safe for healthy adult teeth when used as directed. The most common side effects are temporary tooth sensitivity and mild gum irritation where the strip overlaps the gum.
The bigger risks come from how strips are used. Wearing them longer than directed, doubling up, or using them on teeth with untreated decay, cracks or receding gums can lead to more sensitivity and gum soreness. Strips bought from overseas websites may contain peroxide well above the Australian limit, with no one checking the teeth beforehand. Our article on whether chemist whitening kits are safe goes into these risks further.
Strips compared with dentist take-home trays
Dentist-supplied take-home whitening uses the same basic chemistry, but with three differences that matter. The gel is prescribed at a strength chosen for your teeth. The trays are made from a scan of your mouth, so the gel sits evenly over each tooth, including the edges and the teeth further back. And your teeth and gums are checked first, so problems such as decay or leaking fillings are found before they cause pain.
Custom trays are also reusable. A syringe of gel every so often keeps the shade topped up without starting again. Our guide to how custom whitening trays work explains the fit and the routine, and the teeth whitening page sets out the options at Lumi Dental.
In general market terms, strips and over-the-counter kits sit around $20 to $150, and dentist take-home whitening around $300 to $700. Our teeth whitening cost guide breaks down the ranges by type.
Getting the most from strips if you use them
Brush gently and dry the teeth with a tissue before applying, so the strip sticks evenly. Keep to the time on the pack. If teeth become sensitive, take a day or two off and use a sensitive toothpaste. Avoid strongly coloured food and drink for an hour or so after each strip. And if the result looks patchy or a tooth stays darker than the rest, it is worth having it looked at rather than using more strips.
Questions we are often asked
How long do whitening strips take to work?
Most peroxide strips are used once or twice a day for 10 to 14 days. Some brightening may be visible after a few days, but the full effect is usually seen by the end of the course.
Are Australian strips weaker than overseas ones?
Often, yes. The Dental Board of Australia restricts products above 6% hydrogen peroxide or 18% carbamide peroxide to registered dental practitioners, so higher strength strips sold in other countries cannot be supplied over the counter here.
Do strips work as well as trays?
A systematic review by Serraglio CR and colleagues (Clinical Oral Investigations, 2016) found that peroxide strips and 10% carbamide peroxide in trays produced comparable colour change in short-term trials. Many of the strips studied were stronger than those sold over the counter in Australia, and trays tend to give a more even result on curved or crowded teeth.
Do whitening strips damage enamel?
Used as directed, peroxide strips have not been shown to cause meaningful enamel damage. Products with acidic or abrasive ingredients, or overuse, carry more risk.
If you would like to know which kind of whitening suits your teeth, the free consult and current whitening options are on our current deals page.
