According to Super Savvy Me, wearing a racy red color can make your teeth look whiter instantly. However, it's important to choose the right shade of red in order to achieve your goal. Therefore, if your red lipstick has a blue-based shade, it will make your teeth appear brighter.
Per Red Apple Lipstick, a blue-based red lipstick has a blue hue base color. Simply put, this shade of red has a cool undertone. Blue-based lipsticks not only make your teeth appear whiter, but they also make your complexion look brighter if you have a lighter skin tone. If you are looking for blue-based red lipsticks, you can opt for shades such as raspberry, maroon, carmine, or barn red (via Art In Context).
On the other hand, if you choose orange or yellow tones of red, your teeth will not appear whiter because yellow and orange tones "bring out the same tones in your teeth" (Via Super Savvy Me). Therefore, avoid colors like scarlet and tomato.