If your smile has lost its shine, you can brighten your teeth at home without spending a lot of money. There are many safe, effective, and affordable over-the-counter (OTC) products available. Here are some tips to help you choose the right one for you. First, consider your goals and how much time and money you want to invest. It's recommended to choose a well-known brand that you can buy from a popular store or online. Most teeth whitening kits use a bleaching agent like peroxide, which studies show is safe. However, it's important to check with your dentist to ensure your teeth are healthy enough for whitening. Make sure there are no underlying issues like decay or gum disease that could be causing your teeth to turn yellow. Generally, yellow teeth tend to whiten better than teeth with gray tones. Teeth stained by medications may not lighten well, and bleaching won't work on caps, crowns, veneers, or fillings. You might need to restore your teeth first. Be aware that these products can make your teeth more sensitive. This happens when the peroxide seeps through the enamel and irritates the nerve. Usually, this feeling doesn't last long, but if it does or if your gums change color, see your dentist immediately. You should notice results in about a week. Take a photo of your smile before you start using an OTC whitening kit and another one a week later to compare. If you see a change, it's working. However, keep your expectations realistic. If your teeth aren't brighter after two weeks, contact your dentist. If one box of whitening strips doesn't give good results, more boxes won't help either. You may need a stronger treatment. After you've brightened your smile, follow these tips to maintain it: avoid foods and drinks that stain teeth, brush and floss regularly, and visit your dentist for regular check-ups.