Teeth whitening: results, limits and cost
Professional whitening lightens teeth by four to eight shades depending on the starting point and the result lasts one to three years, while over the counter products are limited by regulation to a concentration far below clinical use.
gelisted editorial team · Updated 15 August 2026
The short version
- Over the counter products are limited to 0,1 per cent hydrogen peroxide.
- Products between 0,1 and 6 per cent require a dental professional.
- In clinic whitening costs 250 € to 500 €.
- Fillings, crowns and veneers do not change colour.
The line between a supermarket product and a clinical one is not the price. It is a concentration limit set by European cosmetics rules.
What the rules allow
European cosmetic product rules limit hydrogen peroxide, present or released, to 0,1 per cent in products sold directly to consumers. Between 0,1 and 6 per cent the product may only be supplied to professionals, and the first application must be carried out or supervised by a dentist who has first excluded risk factors. Above 6 per cent, cosmetic use is not permitted.
| Method | Result | Price |
|---|---|---|
| Whitening toothpaste | removes surface staining | 4 to 12 € |
| Over the counter strips | 1 to 2 shades | 25 to 60 € |
| Supervised home trays | 3 to 6 shades | 180 to 350 € |
| In clinic whitening | 4 to 8 shades | 250 to 500 € |
| Combined clinic and home | 5 to 8 shades | 350 to 650 € |
| Internal whitening of a treated tooth | variable | 150 to 300 € |
| Duration of the result | 1 to 3 years | |
| Top up with trays | 2 to 3 nights | 30 to 60 € |
What does not whiten
Restorations. Fillings, crowns and veneers keep their original colour, so after whitening the natural teeth they can look noticeably darker and may need replacing. That is the hidden cost of whitening a mouth with existing restorations in the visible zone: replacing 2 or 3 composite fillings adds 200 € to 500 € to the budget.
Sensitivity
The most common side effect. It appears during treatment and usually settles within 2 to 7 days of finishing. Gum irritation from gel contact is prevented by well fitted trays. Neither is a reason to abandon the treatment, but both are a reason to speak up: reducing the frequency of application or using a desensitising gel for 2 weeks beforehand changes the experience entirely.
Whitening is not advised under the age of 18, during pregnancy, or with active decay or untreated gum disease.
Keeping the result
The first 48 hours carry the highest risk of restaining, so coffee, tea, cola drinks, dark sauces and tobacco are best avoided. After that, an annual professional clean and a top up of 2 or 3 nights with trays every 12 to 18 months maintain the shade at 30 € to 60 € per top up, rather than repeating the full treatment every few years.
Frequently asked
+How many shades does it lighten?
Four to eight in clinic, 3 to 6 with supervised trays and 1 to 2 with over the counter strips.
+Why do pharmacy products do less?
Because the rules limit hydrogen peroxide to 0,1 per cent in products sold directly to consumers.
+Does it whiten fillings and crowns?
No. Restorations keep their colour and may need replacing after the natural teeth are lightened.
+Is sensitivity normal?
Yes, it is the most common effect and usually settles within two to seven days of finishing.
+How long does the result last?
One to three years, with top ups of two or three nights every 12 to 18 months.
Sources
- 1Regulation (EC) 1223/2009 on cosmetic products, European Union (August 2026)
- 2Ministerio de Sanidad, Gobierno de España (August 2026)