The products available online, in drugstores or pharmacies are often dosed too low to achieve a visible result, or contain ingredients that have no bleaching effect at all.
In addition, bleaching at home has to be done without medical supervision or prior advice. The bleaching agent is applied to the tooth surface with brushes or gels, for example. Neither the gums nor the oral cavity are protected.
Whitening should also only be carried out if the teeth are healthy and there is no damage or disease. A dentist should check this beforehand. When you have your teeth bleached in a dental practice, you receive detailed advice on the different methods and the results you can expect, and you are professionally looked after during the treatment. You don't have this security if, for example, you order products online or from the pharmacy.