It's definitely not a substitute for washing your hands.

Hand sanitizer is commonplace in schools, hospitals, and purses everywhere. In the early 2000s, travel-sized hand sanitizers were even one of the hottest back-to-school accessories, thanks to Bath and Body Works and its amazing scents. Hand sanitizer has long been seen as a quick fix to help prevent the spreading of germs during cold and flu season. It’s convenient and portable, so it’s no wonder that many of us have gotten in the habit of using it regularly, but is hand sanitizer really doing us any good? Or is there a cost to its convenience?

We did our research to find answers to some of these common questions surrounding the ultra-convenient germ-fighter. Here’s the good news: You don’t have to quit your habit of using hand sanitizer altogether—you just have to know the right way to use it.

1 Is hand sanitizer bad for you?

There’s some concern surrounding hand sanitizer that it can have a too-much-of-a-good-thing effect, causing antibiotic resistance and creating superbugs. Fortunately, this has largely been disproved. According to the Centers for Disease Control and Prevention (CDC), the ingredients in hand sanitizers, mostly ethyl alcohol, work differently than antibiotics do to attack germs. While overuse of antibiotics has been identified as problematic, the CDC assures us that with the use of hand sanitizers, “there is no chance for the germs to adapt or develop resistance.”

2 Hand sanitizer vs. soap and water

According to Tiffany Wiksten, the manager of infection prevention and control at Rush University Medical Center, both using hand sanitizer and washing hands with soap and water are “acceptable ways to perform hand hygiene, as long as they’re used correctly.” Knowing when to use soap and water versus hand sanitizer may mostly involve common sense, but it’s important to understand their different functions.

3 How and when to use soap and water

The most basic way to know when you should use soap and water to clean your hands is when they’re visibly dirty. Hand sanitizer is no substitute for cleaning off grime and dirt. Good hygiene and good manners go hand in hand (no pun intended), and it’s recommended that you wash your hands with soap and water before preparing or eating food to avoid cross contamination—and of course, you should always wash them after using the bathroom. Soap and water is also more effective than hand sanitizer at fighting off certain germs, such as norovirus and C. dif.

The CDC recommends washing your hands for at least 15 seconds to ensure all areas of your hands get a thorough clean.

4 How and when to use hand sanitizer

Hand sanitizer can’t and shouldn’t take the place of soap and water altogether, but its convenience factor keeps the product from going obsolete. As long as you are still regularly using soap and water, hand sanitizer is an effective way to fill in the holes when you don’t have access to a sink. It’s especially helpful for healthcare professionals who need to disinfect their hands frequently, or for your own peace of mind when you’ve been around highly populated areas and surfaces.

Just make sure you are just as thorough when applying hand sanitizer as you should be when using soap and water: The thumbs, fingertips, and between the fingers are commonly missed spots in hand sanitizer application, according to the CDC.

RELATED: You’ve Probably Been Washing Your Hands Wrong—Here’s the Right Way to Do It (and Avoid Getting Sick)

5 What kind of hand sanitizer should you use?

With so many different scents and accessories, hand sanitizer sometimes becomes more of a novelty item than a product meant for hand hygiene. When buying hand sanitizer, be sure to find an alcohol-based solution that will actually get the job done.

“Alcohol-based hand sanitizers work by denaturing the proteins of germs, which kills them,” Wiksten says. Hand sanitizers that contain at least 60 to 95 percent alcohol are said to be most effective at warding off germs. According to the CDC, hand sanitizers without this amount of alcohol content may either be ineffective on many types of germs or simply work to reduce the growth of germs, rather than kill them.